RESUMO
BACKGROUND: The emergence of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant S. aureus (VRSA) strains is a significant public health concern. Considering the high morbidity and mortality of invasive S. aureus infections and multi-drug resistant strains, there is an urgent need for non-antibiotic immune-based approaches to cure these infections. Despite all efforts, vaccine candidates targeting S. aureus failed in human clinical trials, and no approved vaccine is available against this pathogen. Therefore, this study aimed to introduce suitable candidates for immunization against S. aureus using a comprehensive reverse vaccinology approach. METHODS: In this study, we retrieved putative immunogenic targets from three different levels (literature review, automated reverse vaccinology, and manual reverse vaccinology) and evaluated them using several immunoinformatics analyses including antigenicity, allergenicity, PSI-BLAST to human proteome, physiochemical properties, B-cell, and T-cell epitopes. In the next step, the quartile method scoring was used to the shortlisted proteins. Finally, the molecular docking and immune simulation of immunogenic targets were performed. RESULTS: This study presents 12 vaccine candidates, including three enzymatic proteins (WP_000222271.1, WP_001170274, and WP_000827736.1), three cell wall-associated proteins (WP_001125631.1, WP_000731642, and WP_000751265.1), two hemolysins (WP_000594517.1, and WP_000916697.1), one secretion involved protein (WP_000725226.1), one hemeiron binding protein (WP_001041573.1), one superantigen like protein (WP_000668994.1) and one hypothetical proteins (WP_000737711.1). CONCLUSION: Through quartile scoring method, immune simulation and molecular docking, four promising targets including lytic transglycosylase IsaA, HlgA, secretory antigen precursor SsaA, and heme uptake protein IsdB were selected as the shortlisted proteins. It seems that a polarized immunization (Th1/Th17) response is needed for protection against this bacterium. An optimized formulation based on these putative immunogenic proteins and a wisely adjuvant selection may drive the immune system toward a full protection.
Assuntos
Staphylococcus aureus Resistente à Meticilina/fisiologia , Infecções Estafilocócicas/prevenção & controle , Vacinas Antiestafilocócicas/imunologia , Vacinologia/métodos , Humanos , Simulação de Acoplamento Molecular , Vacinas de Subunidades Antigênicas/imunologiaRESUMO
HI, a fusion protein that consists of the alpha-toxin (Hla) and the N2 domain of iron surface determinant B (IsdB), is one of the antigens in the previously reported S. aureus vaccine rFSAV and has already entered phase II clinical trials. Previous studies revealed that HI is highly immunogenic in both mice and healthy volunteers, and the humoral immune response plays key roles in HI-mediated protection. In this study, we further investigated the protective efficacy of immunization with HI plus four different adjuvants in a mouse bacteremia model. Results showed that HI-mediated protection was altered in response to different adjuvants. Using antisera from immunized mice, we identified seven B-cell immunodominant epitopes on Hla and IsdB, including 6 novel epitopes (Hla1-18, Hla84-101, Hla186-203, IsdB342-359, IsdB366-383, and IsdB384-401). The immunodominance of B-cell epitopes, total IgG titers and the levels of IFN-γ and IL-17A from mice immunized with HI plus different adjuvants were different from each other, which may explain the difference in protective immunity observed in each immunized group. Thus, our results indicate that adjuvants largely affected the immunodominance of epitopes and the protective efficacy of HI, which may guide further adjuvant screening for vaccine development and optimization.
Assuntos
Bacteriemia/imunologia , Toxinas Bacterianas/imunologia , Proteínas de Transporte de Cátions/imunologia , Epitopos de Linfócito B/imunologia , Proteínas Hemolisinas/imunologia , Epitopos Imunodominantes/imunologia , Infecções Estafilocócicas/prevenção & controle , Animais , Bacteriemia/prevenção & controle , Modelos Animais de Doenças , Feminino , Imunização Passiva , Imunoterapia Adotiva , Interferon gama/metabolismo , Interleucina-17/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Infecções Estafilocócicas/imunologia , Vacinas Antiestafilocócicas/administração & dosagem , Vacinas Antiestafilocócicas/imunologiaRESUMO
Morel's disease is a form of abscessing lymphadenitis of sheep and goats caused by Staphylococcus aureus subspecies anaerobius. In Europe and Africa, the disease is linked to S. aureus of multilocus sequence type 1464. In an outbreak recorded in 2015 in a flock of 530 animals in the district of Nymburk, Czech Republic, Europe, the causative agent was cultured and subsequently confirmed by Maldi-TOF. Neither antibiotic therapy nor surgical interventions met any success, although the strain isolated was found to be sensitive to antibiotics used. Vaccination and revaccination with inactivated autogenous vaccine administered subcutaneously was relatively successful. Subsequent multilocus sequence typing revealed the presence of new S. aureus sequence type 3756, different from 1464 in three out of seven genes typed. The isolate thus represents a new sequence type of Staphylococcus aureus ssp. anaerobius which should be considered as a causative agent of Morel's disease.
Assuntos
Antibacterianos/uso terapêutico , Linfadenite/tratamento farmacológico , Linfadenite/microbiologia , Doenças dos Ovinos/tratamento farmacológico , Infecções Estafilocócicas/veterinária , Vacinas Antiestafilocócicas/imunologia , Staphylococcus aureus/classificação , Animais , República Tcheca , Linfadenite/veterinária , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus , Ovinos , Doenças dos Ovinos/microbiologia , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/imunologia , Staphylococcus aureus/isolamento & purificação , VacinaçãoRESUMO
Mastitis is an inflammatory condition of the udder that occurs as a result of the release of leucocytes into the udder in a response to bacterial invasion. The major causes of mastitis are an array of gram positive and negative bacteria, however, algae, virus, fungi, mechanical or thermal injury to the gland have also been identified as possible causes. Mastitis vaccines are yet to be developed using Malaysian local isolate of bacteria. The objective of the present experimental trial was to develop a monovalent vaccine against mastitis using S. aureus of Malaysian isolate and to evaluate the clinical responses such as temperature, respiratory rates and heart rates in vaccinated cows. S. aureus is a major causative bacteria in clinical and subclinical types of mastitis in cows. Four concentrations of the bacterin (106, 107, 108 and 109â¯cfu/ml of the local isolate of S. aureus) were prepared using Aluminium potassium sulfate adjuvant. Thirty cows were grouped into four treatment groups (B, C, D and E) with a fifth group as control (A). These groups were vaccinated intramuscularly(IM) with the prepared monovalent vaccine and its influence on the vital signs were intermittently measured. The mean of rectal temperature was significantly different (pË 0.05) at 0hr Post Vaccination [1]" in groups D and E (39.5⯱â¯0.15⯰C and 39.4⯱â¯0.15⯰C respectively) and at 3â¯hâ¯PV in groups C, D and E (39.8⯱â¯0.14⯰C, 39.9⯱â¯0.14⯰C and 40.3⯱â¯0.14⯰C respectively) compared to the control group. This indicated a sharp increased rectal temperatures between 0hr and 3â¯hâ¯PV in groups C, D and E which later declined at 24â¯hâ¯PV. The mean of rectal temperature of group E was significantly different (pË 0.05) at weeks 1 and 2â¯PV (39.87⯱â¯0.19⯰C and 39.80⯱â¯0.18⯰C respectively) compared to the control group. The mean of heart rate was significantly different (pË 0.05) at week 1â¯PV in groups D and E (83.0⯱â¯3.8 beats/minute and 80.0⯱â¯3.8⯰C respectively) compared to control. A trending decrease was however observed in heart rates of group E from weeks through 4â¯PV and in group D from weeks 1 through 3â¯PV. The mean of respiratory rates was significantly different (pË 0.05) at week 3â¯PV in group B and D (31.0⯱â¯1.2 breaths/minute and 28.0⯱â¯1.2 breaths/minute) compared to control. In conclusion, this study highlights responses of these vital signs due to vaccination against S. aureus causing mastitis in cows. To the best of our knowledge the findings of this study adds value to the shallow literature on vital signs alterations in cows vaccinated against mastitis as elevated levels of temperature and heart rates of group D and E indicated obvious response.
Assuntos
Vacinas Bacterianas/imunologia , Mastite Bovina/prevenção & controle , Infecções Estafilocócicas/veterinária , Vacinas Antiestafilocócicas/imunologia , Staphylococcus aureus/imunologia , Adjuvantes Imunológicos/administração & dosagem , Compostos de Alúmen/administração & dosagem , Animais , Vacinas Bacterianas/administração & dosagem , Bovinos , Injeções Intramusculares , Mastite Bovina/patologia , Infecções Estafilocócicas/patologia , Infecções Estafilocócicas/prevenção & controle , Vacinas Antiestafilocócicas/administração & dosagem , Resultado do TratamentoRESUMO
Staphylococcus aureus is a major pathogen in both community and hospital settings. It is a significant etiological agent to treat in healthcare-related infections due to both its ability to cause invasive infection as well as to form biofilm on biomaterials and the high prevalence of resistance to first line antibiotics. The most challenging preventive strategy is vaccine development to guarantee a full and durable protection from staphylococcal diseases in all different high-risk populations, even if the lack of a known correlate of protection from S. aureus is a major hindrance to this effort. We aimed to review the most recent advances in the field of vaccinology against S. aureus, highlighting the potential for future application of the different experimental vaccine types. Several vaccines have completed their preclinical phase of development and others have been tested in humans, however no successful phase III clinical trial has yet been completed.
Assuntos
Infecções Estafilocócicas/prevenção & controle , Vacinas Antiestafilocócicas/imunologia , Staphylococcus aureus , Ensaios Clínicos como Assunto , Avaliação Pré-Clínica de Medicamentos , Humanos , Infecções Estafilocócicas/microbiologiaRESUMO
The predominant Staphylococcus aureus (S. aureus), an etiological agent of camel mastitis is becoming drug resistant that invites prevention and control strategies. Vaccine production would have a valuable impact on public health. Therefore, in present study, inactivated vaccine with different adjuvants was prepared and evaluated against S. aureus. The vaccinal isolate recovered from camel subclinical mastitis was coagulase positive (PCR based), having expressed pseudocapsule, holding alpha-beta hemolysin characteristics, and multiple drug resistant. Inactivated alum precipitated S. aureus vaccine (APSV) and oil adjuvant S. aureus vaccine (OASV) were prepared after confirming its antigenicity in rabbits. Three groups of rabbits were randomly inoculated with APSV, OASV, and placebo (Unvaccinated, UV). Each group was further divided into two groups based on single and booster dose inoculation. Booster dose of vaccines in rabbits at day 15th of primary inoculation was given. Serum samples were taken on 15, 30, 45 and 60 days of primary inoculation from all rabbits. Analysis of variance was applied to compare geometric mean titer (GMT) of three groups, while t-test was applied to estimate the difference between single and booster dose response. The study found 1010â¯CFU/mL S. aureus as standard bacterial load for vaccines with higher and sustained antigenicity. The vaccines were safe from morbidity and mortality, and proved effective and stable for 7 and 4â¯monthsâ¯at 25⯰C and 37⯰C, respectively. The OASV produced significantly (pâ¯<â¯0.05) higher immune response followed by APSV throughout trial. The highest GMT by APSV and OASV vaccines with single dose inoculation was 37.92 and 69.92â¯at day 45th post primary inoculation, respectively. Similarly, 59.20 and 142.40 GMTs were noted with booster dose in case of APSV and OASV, respectively. The booster dose presented significantly (pâ¯<â¯0.05) higher GMT than that of single dose inoculation of vaccines. The study concluded APSV and OASV safe, effective, and stable with significant immunogenic results in experimental rabbits.
Assuntos
Imunogenicidade da Vacina/imunologia , Infecções Estafilocócicas/imunologia , Infecções Estafilocócicas/prevenção & controle , Vacinas Antiestafilocócicas/imunologia , Staphylococcus aureus/imunologia , Vacinação , Vacinas de Produtos Inativados/imunologia , Adjuvantes Imunológicos/administração & dosagem , Compostos de Alúmen , Animais , Anticorpos Antibacterianos/sangue , Antígenos de Bactérias/imunologia , Carga Bacteriana , Proteínas de Bactérias/imunologia , Camelus , Coagulase , Modelos Animais de Doenças , Farmacorresistência Bacteriana Múltipla , Feminino , Proteínas Hemolisinas , Imunização Secundária , Mastite/imunologia , Mastite/microbiologia , Mastite/prevenção & controle , Óleo Mineral/administração & dosagem , Coelhos , Infecções Estafilocócicas/microbiologia , Vacinas Antiestafilocócicas/administração & dosagem , Staphylococcus aureus/patogenicidade , Fatores de Tempo , Vacinas de Produtos Inativados/administração & dosagemRESUMO
BACKGROUND: Staphylococcus aureus is a major bacterial pathogen capable of causing a range of infections in humans from gastrointestinal disease, skin and soft tissue infections, to severe outcomes such as sepsis. Staphylococcal infections in humans can be frequent and recurring, with treatments becoming less effective due to the growing persistence of antibiotic resistant S. aureus strains. Due to the prevalence of antibiotic resistance, and the current limitations on antibiotic development, an active and highly promising avenue of research has been to develop strategies to specifically inhibit the activity of virulence factors produced S. aureus as an alternative means to treat disease. OBJECTIVE: In this review we specifically highlight several major virulence factors produced by S. aureus for which recent advances in antivirulence approaches may hold promise as an alternative means to treating diseases caused by this pathogen. Strategies to inhibit virulence factors can range from small molecule inhibitors, to antibodies, to mutant and toxoid forms of the virulence proteins. CONCLUSION: The major prevalence of antibiotic resistant strains of S. aureus combined with the lack of new antibiotic discoveries highlight the need for vigorous research into alternative strategies to combat diseases caused by this highly successful pathogen. Current efforts to develop specific antivirulence strategies, vaccine approaches, and alternative therapies for treating severe disease caused by S. aureus have the potential to stem the tide against the limitations that we face in the post-antibiotic era.
Assuntos
Antibacterianos/farmacologia , Resistência Microbiana a Medicamentos/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Vacinas Antiestafilocócicas/imunologia , Fatores de Virulência/antagonistas & inibidores , Antibacterianos/uso terapêutico , Anticorpos Antibacterianos/sangue , Ensaios Clínicos como Assunto , Descoberta de Drogas , Humanos , Staphylococcus aureus Resistente à Meticilina/imunologia , Staphylococcus aureus Resistente à Meticilina/metabolismo , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/imunologia , Infecções Estafilocócicas/virologiaRESUMO
BACKGROUND: The decline in immune function with age is a challenge to vaccine development. Following an initial study in adults aged 18-64years, this study evaluated the safety and immunogenicity of Staphylococcus aureus (S. aureus) 4-antigen (SA4Ag) and 3-antigen (SA3Ag) vaccine in older adults. SA3Ag included capsular polysaccharide serotypes 5 and 8 (CP5 and CP8) conjugated to the nontoxic mutant form of diphtheria toxin (CRM197) and a recombinant version of clumping factor A (ClfA). SA4Ag included these antigens, with the addition of a recombinant manganese transporter C (rP305A or MntC). Both vaccines were unadjuvanted. METHODS: In this double-blind, sponsor-unblinded, placebo-controlled, phase 1/2 study, 284 healthy adults (aged 65-85years) were randomised to receive a single dose of one of three formulations of SA4Ag with escalating dose levels of rP305A, SA3Ag, or placebo. Functional immune responses were measured using opsonophagocytic activity (OPA) killing and fibrinogen-binding inhibition (FBI) assays; immunogenicity was also assessed using a competitive Luminex® immunoassay (cLIA). T-cell responses were measured in a small subgroup of subjects using intracellular cytokine staining (ICS) assays. RESULTS: The results demonstrated rapid and robust functional immune responses to all antigens in healthy older adults. A high proportion of active vaccine recipients met the pre-defined antibody thresholds for each antigen at Day 29. SA4Ag elicited a dose-level response to rP305A with up to a 13-fold rise in cLIA titres at Day 29. Opsonophagocytic activity (OPA) assays showed >50- and >20-fold rises in functional titres using S. aureus strains expressing CP5 and CP8, respectively, at Day 29. T-cell cytokine responses were not substantially above background levels. There were no safety concerns in this study population and no increases in adverse events with higher rP305A dose levels. CONCLUSIONS: Single-dose vaccination of SA4Ag and SA3Ag in healthy adults aged 65-85years safely induced rapid and robust functional immune responses, supporting further development of SA4Ag for the prevention of S. aureus disease in adults up to age 85years. TRIAL REGISTRATION NUMBER: NCT01643941.
Assuntos
Antígenos de Bactérias/imunologia , Vacinas Antiestafilocócicas/efeitos adversos , Vacinas Antiestafilocócicas/imunologia , Staphylococcus aureus/imunologia , Adjuvantes Imunológicos/metabolismo , Idoso , Idoso de 80 Anos ou mais , Anticorpos Antibacterianos/sangue , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/metabolismo , Citocinas/análise , Método Duplo-Cego , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/epidemiologia , Feminino , Humanos , Masculino , Proteínas Opsonizantes/sangue , Fagocitose , Placebos/administração & dosagem , Polissacarídeos Bacterianos/imunologia , Vacinas Antiestafilocócicas/administração & dosagem , Linfócitos T/imunologia , Resultado do Tratamento , Vacinas Conjugadas/administração & dosagem , Vacinas Conjugadas/imunologiaRESUMO
Staphylococcus aureus is a pathogen that causes a variety of infections in humans. Methicillin-resistant S. aureus, which is an antibiotic-resistant form, is responsible for nosocomial staphylococcal infections, whose frequency is increasing in healthy people. Thereby, the development of novel techniques is required to overcome this bacterial infection. In this context, the use of vaccines to control infections is an appropriate alternative. In this study, immunoinformatics analysis is used on three antigenic determinants as vaccine candidates, and a novel multi-epitope vaccine is designed to induce cellular, humoral, and innate immune responses against S. aureus. Alpha-enolase, clumping factor A, and iron surface determinant B were selected as the protective antigens; and phenol-soluble modulin alpha 4was applied as the adjuvant. Epitopes identification was done for each antigen using various immunoinformatics servers. Moreover, the tertiary structure of our protein vaccine was predicted and validated. Subsequently, the best-modeled protein structure was used for the refinement process. There fined model was then applied for docking studies with Toll-like receptor 2 (TLR2).In the next step, molecular dynamics (MD) simulation was used to evaluate the stability of vaccine molecule and TLR2-vaccine complex. The high ranked epitopes were selected from the mentioned antigens. The selected epitopes and the adjuvant were fused together by proper linkers. Then, the modeled protein structure was selected and validated. Validation results indicated that the initial model needs refinement. After a refinement process, the final model was generated. Finally, the best-docked model of vaccine and TLR2 complex was selected. In this research, we attempted to design an efficient subunit vaccine, which could stimulate humoral and cellular immune responses. Therefore, we expect that our designed vaccine could defeat antibiotic-resistant staphylococcal infections.
Assuntos
Infecções Estafilocócicas/prevenção & controle , Vacinas Antiestafilocócicas/química , Staphylococcus aureus/imunologia , Vacinas de Subunidades Antigênicas/química , Sequência de Aminoácidos , Sítios de Ligação , Biologia Computacional , Epitopos/imunologia , Humanos , Simulação de Dinâmica Molecular , Infecções Estafilocócicas/imunologia , Infecções Estafilocócicas/microbiologia , Vacinas Antiestafilocócicas/imunologia , Vacinas de Subunidades Antigênicas/imunologiaRESUMO
In a recent article, X. Li et al. [mBio 7(1):e02232-15, 2016, http://dx.doi.org/10.1128/mBio.02232-15] investigate the utility of a vaccine composed of the Staphylococcus aureus protein clumping factor A (ClfA) in protecting mice from S. aureus infection. ClfA, one of the first proteins to be identified as a potential vaccine antigen for S. aureus prophylaxis, is currently a component of several investigational vaccines. The authors conclude that ClfA may not be effective for S. aureus prophylaxis. In contrast, previously published papers reporting positive data suggested that ClfA was potentially an important vaccine target to prevent invasive S. aureus disease. This commentary addresses the observed differences between the findings of Li et al. and those from other publications, highlighting the importance for preclinical vaccine antigen assessments to reflect the biological role of said antigen in virulence and, consequently, the importance of choosing appropriate preclinical disease models to test such antigens.
Assuntos
Coagulase/imunologia , Infecções Estafilocócicas/prevenção & controle , Vacinas Antiestafilocócicas/imunologia , Staphylococcus aureus/imunologia , Animais , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Camundongos , Vacinas Antiestafilocócicas/isolamento & purificação , Resultado do Tratamento , Vacinas de Subunidades Antigênicas/imunologia , Vacinas de Subunidades Antigênicas/isolamento & purificaçãoRESUMO
Vaccination strategies for Staphylococcus aureus, particularly methicillin-resistant S. aureus (MRSA) infections have attracted much research attention. Recent efforts have been made to select manganese transport protein C, or manganese binding surface lipoprotein C (MntC), which is a metal ion associated with pathogen nutrition uptake, as potential candidates for an S. aureus vaccine. Although protective humoral immune responses to MntC are well-characterised, much less is known about detailed MntC-specific B cell epitope mapping and particularly epitope vaccines, which are less-time consuming and more convenient. In this study, we generated a recombinant protein rMntC which induced strong antibody response when used for immunisation with CFA/IFA adjuvant. On the basis of the results, linear B cell epitopes within MntC were finely mapped using a series of overlapping synthetic peptides. Further studies indicate that MntC113-136, MntC209-232, and MntC263-286 might be the original linear B-cell immune dominant epitope of MntC, furthermore, three-dimensional (3-d) crystal structure results indicate that the three immunodominant epitopes were displayed on the surface of the MntC antigen. On the basis of immunodominant MntC113-136, MntC209-232, and MntC263-286 peptides, the epitope vaccine for S. aureus induces a high antibody level which is biased to TH2 and provides effective immune protection and strong opsonophagocytic killing activity in vitro against MRSA infection. In summary, the study provides strong proof of the optimisation of MRSA B cell epitope vaccine designs and their use, which was based on the MntC antigen in the development of an MRSA vaccine.
Assuntos
Proteínas de Bactérias/imunologia , Proteínas de Transporte de Cátions/imunologia , Epitopos de Linfócito B/imunologia , Epitopos Imunodominantes/imunologia , Staphylococcus aureus Resistente à Meticilina/imunologia , Infecções Estafilocócicas/prevenção & controle , Vacinas Antiestafilocócicas/imunologia , Animais , Anticorpos Antibacterianos/biossíntese , Anticorpos Antibacterianos/imunologia , Antígenos de Bactérias/imunologia , Proteínas de Bactérias/genética , Proteínas de Transporte de Cátions/genética , Mapeamento de Epitopos , Feminino , Células HL-60 , Hemocianinas/imunologia , Humanos , Manganês , Camundongos , Camundongos Endogâmicos BALB C , Fagocitose , Infecções Estafilocócicas/imunologia , Vacinas Antiestafilocócicas/administração & dosagem , Vacinas Antiestafilocócicas/genética , Vacinas Conjugadas/imunologia , Vacinas Sintéticas/imunologiaRESUMO
UNLABELLED: Treatment of Staphylococcus aureus infections has become increasingly difficult because of the emergence of multidrug-resistant isolates. Development of a vaccine to prevent staphylococcal infections remains a priority. To determine whether clumping factor A (ClfA) is a good target protein for inclusion in a multivalent vaccine, we evaluated its efficacy in a variety of relevant staphylococcal infection models, challenging with different S. aureus strains. ClfA adsorbed to Alhydrogel and mixed with Sigma Adjuvant System was more immunogenic and stimulated a more robust Th17 response than ClfA administered with alum alone. ClfA immunization induced the production of functional antibodies in rabbits and mice that blocked S. aureus binding to fibrinogen and were opsonic for S. aureus strains that produced little or no capsular polysaccharide. Mice immunized with ClfA showed a modest reduction in the bacterial burden recovered from subcutaneous abscesses provoked by S. aureus USA300 strain LAC. In addition, the ClfA vaccine reduced lethality in a sepsis model following challenge with strain Newman, but not ST80. Vaccination with ClfA did not protect against surgical wound infection, renal abscess formation, or bacteremia. Passive immunization with antibodies to ClfA did not protect against staphylococcal bacteremia in mice or catheter-induced endocarditis in rats. Some enhancement of bacteremia was observed by ClfA immunization or passive administration of ClfA antibodies when mice were challenged by the intraperitoneal route. Although rodent models of staphylococcal infection have their limitations, our data do not support the inclusion of ClfA in an S. aureus multivalent vaccine. IMPORTANCE: Antibiotics are often ineffective in eradicating Staphylococcus aureus infections, and thus, a preventative vaccine is sorely needed. Two single-component vaccines and two immunoglobulin preparations failed to meet their designated endpoints in phase III clinical trials. Importantly, recipients of an S. aureus surface protein (iron surface determinant B) vaccine who developed a staphylococcal infection experienced a higher rate of multiorgan failure and mortality than placebo controls, raising safety concerns. Multicomponent S. aureus vaccines have now been generated, and several include surface protein clumping factor A (ClfA). We immunized mice with ClfA and generated a robust T cell response and serum antibodies that were functional in vitro. Nonetheless, ClfA was not protective in a number of relevant animal models of S. aureus infection, and high levels of ClfA antibodies enhanced bacteremia when mice were challenged with community-acquired methicillin-resistant S. aureus strains. Evidence supporting ClfA as a vaccine component is lacking.
Assuntos
Antígenos de Bactérias/imunologia , Coagulase/imunologia , Infecções Estafilocócicas/prevenção & controle , Vacinas Antiestafilocócicas/imunologia , Abscesso/microbiologia , Adjuvantes Imunológicos/administração & dosagem , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Antibacterianos/uso terapêutico , Carga Bacteriana , Avaliação Pré-Clínica de Medicamentos , Camundongos , Camundongos Endogâmicos C57BL , Placebos/administração & dosagem , Ratos Sprague-Dawley , Sepse/mortalidade , Vacinas Antiestafilocócicas/administração & dosagem , Análise de Sobrevida , Vacinas de Subunidades Antigênicas/administração & dosagem , Vacinas de Subunidades Antigênicas/imunologiaRESUMO
We assessed the safety, reactogenicity and immunogenicity of a staphylococcal vaccine combining capsular polysaccharides types 5 and 8 (CPS5/8), conjugated to tetanus toxoid (TT), with mutated detoxified α-toxin (AT) and clumping factor A (ClfA). In this phase I, randomized, placebo-controlled, observer-blind trial (NCT01160172), 88 healthy 18- to 40-year-olds received CPS5-TT/CPS8-TT/AT/ClfA vaccine (5/5/10/10 µg or 10/10/30/30 µg dose, each with or without AS03B adjuvant) or saline, at months 0, 1, 6. Solicited and unsolicited adverse events (AEs) were recorded for 7 and 30 d post-vaccination, respectively; potential immune-mediated diseases (pIMDs) and serious AEs (SAEs) were recorded throughout the study. Humoral and antigen-specific CD4(+)/CD8(+) T-cell immunity were assessed from Day (D) 0 to D540 post-vaccination. The most frequently reported solicited local and general AEs were pain (78.6%-100% of subjects), fatigue (36.4%-93.3% of subjects post-dose 1-2) and headache (20%-44.4% of subjects post-dose 3). Overall, 4 SAEs and 2 potential immune-mediated diseases (pIMDs) (none fatal or vaccine-related) were reported. For each antigen, pre-vaccination seropositivity rates were high (85.7%-100%) and geometric mean concentrations (GMCs) in vaccine recipients sharply increased from D0 to D14, then plateaued to study end. Exploratory group comparisons suggested higher GMCs with higher dosage, without AS03B effect. Vaccine-induced antibodies were functional (CPS5 opsonophagocytic assays, and AT/ClfA inhibition assays). AT- and ClfA-specific CD4(+) T-cells with Th0/Th1 cytokine profile were induced at low levels (median <0.05%) by each formulation (intracellular cytokine staining). In conclusion, no safety concerns were identified and each vaccine formulation induced robust humoral immune responses after the first vaccine dose.
Assuntos
Infecções Estafilocócicas/prevenção & controle , Vacinas Antiestafilocócicas/efeitos adversos , Vacinas Antiestafilocócicas/imunologia , Adjuvantes Imunológicos/administração & dosagem , Adolescente , Adulto , Anticorpos Antibacterianos/sangue , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Combinação de Medicamentos , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/epidemiologia , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/patologia , Feminino , Voluntários Saudáveis , Humanos , Masculino , Placebos/administração & dosagem , Polissorbatos/administração & dosagem , Método Simples-Cego , Esqualeno/administração & dosagem , Infecções Estafilocócicas/imunologia , Adulto Jovem , alfa-Tocoferol/administração & dosagemRESUMO
Staphylococcal infections are a major source of global morbidity and mortality. Currently there exists no antistaphylococcal vaccine in clinical use. Previous animal studies suggested a possible role for purified lipoteichoic acid as a vaccine target for eliciting protective IgG to several Gram-positive pathogens. Since the highly conserved (poly)glycerolphosphate backbone of lipoteichoic acid is a major antigenic target of the humoral immune system during staphylococcal infections, we developed a synthetic method for producing glycerol phosphoramidites to create a covalent 10-mer of (poly)glycerolphosphate for potential use in a conjugate vaccine. We initially demonstrated that intact Staphylococcus aureus elicits murine CD4(+) T cell-dependent (poly)glycerolphosphate-specific IgM and IgG responses in vivo. Naive mice immunized with a covalent conjugate of (poly)glycerolphosphate and tetanus toxoid in alum plus CpG-oligodeoxynucleotides produced high secondary titers of serum (poly)glycerolphosphate-specific IgG. Sera from immunized mice enhanced opsonophagocytic killing of live Staphylococcus aureus in vitro. Mice actively immunized with the (poly)glycerolphosphate conjugate vaccine showed rapid clearance of staphylococcal bacteremia in vivo relative to mice similarly immunized with an irrelevant conjugate vaccine. In contrast to purified, natural lipoteichoic acid, the (poly)glycerolphosphate conjugate vaccine itself exhibited no detectable inflammatory activity. These data suggest that a synthetic (poly)glycerolphosphate-based conjugate vaccine will contribute to active protection against extracellular Gram-positive pathogens expressing this highly conserved backbone structure in their membrane-associated lipoteichoic acid.
Assuntos
Glicerofosfatos/imunologia , Infecções Estafilocócicas/prevenção & controle , Vacinas Antiestafilocócicas/administração & dosagem , Adjuvantes Imunológicos/administração & dosagem , Compostos de Alúmen/administração & dosagem , Animais , Bacteriemia/imunologia , Linfócitos T CD4-Positivos/imunologia , Feminino , Glicerofosfatos/administração & dosagem , Soros Imunes/administração & dosagem , Soros Imunes/imunologia , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Testes de Sensibilidade Microbiana , Oligodesoxirribonucleotídeos/administração & dosagem , Infecções Estafilocócicas/imunologia , Vacinas Antiestafilocócicas/imunologia , Toxoide Tetânico/imunologia , Vacinas Conjugadas/administração & dosagem , Vacinas Conjugadas/imunologia , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/imunologiaRESUMO
Bacteremia is the second leading cause of death in patients with end-stage renal disease who are on hemodialysis. A vaccine eliciting long-term immune responses against Staphylococcus aureus in patients on chronic hemodialysis may reduce the incidence of bacteremia and its complications in these patients. V710 is a vaccine containing iron surface determinant B (IsdB), a highly conserved S. aureus surface protein, which has been shown to be immunogenic in healthy subjects. In this blinded phase II immunogenicity study, 206 chronic hemodialysis patients between the ages of 18 and 80 years old were randomized to receive 60 µg V710 (with or without adjuvant), 90 µg V710 (with adjuvant), or a placebo in various combinations on days 1, 28, and 180. All 201 vaccinated patients were to be followed through day 360. The primary hypothesis was that at least 1 of the 3 groups receiving 2 V710 doses on days 1 and 28 would have a ≥2.5 geometric mean fold rise (GMFR) in anti-IsdB IgG titers over the baseline 28 days after the second vaccination (day 56). At day 56, all three groups receiving 2 doses of V710 achieved a ≥2.5 GMFR in anti-IsdB antibodies compared to the baseline (P values of <0.001 for all 3 groups), satisfying the primary immunogenicity hypothesis. None of the 33 reported serious adverse experiences were considered vaccine related by the investigators. V710 induced sustained antibody responses for at least 1 year postvaccination in patients on chronic hemodialysis.
Assuntos
Bacteriemia/prevenção & controle , Proteínas de Transporte de Cátions/imunologia , Falência Renal Crônica/imunologia , Diálise Renal , Infecções Estafilocócicas/prevenção & controle , Vacinas Antiestafilocócicas/efeitos adversos , Vacinas Antiestafilocócicas/imunologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Bacteriemia/imunologia , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Placebos/administração & dosagem , Infecções Estafilocócicas/imunologia , Vacinas Antiestafilocócicas/administração & dosagem , Staphylococcus aureus/imunologia , Adulto JovemRESUMO
Merck V710 is a novel vaccine that contains the highly conserved Staphylococcus aureus iron surface determinant B (IsdB) protein. V710 has induced positive immune responses in healthy subjects. The purpose of the two studies described herein was to evaluate the immunogenicity and safety of two different formulations of V710. Both studies were randomized, controlled, double-blind, parallel-group trials. Study 1 compared liquid, aluminum-adjuvanted V710 (30 µg) with liquid, non-adjuvanted V710 (30 µg) in a 1:1 ratio in 64 healthy adults (18-70 years). Study 2 compared non-adjuvanted lyophilized V710 (60 µg) with saline placebo in a 4:1 ratio in 51 healthy adults (18-80 years). Blood was collected at screening and up to Day 360 postvaccination in Study 1, and at screening and up to Day 84 postvaccination in Study 2. Sera were analyzed for IsdB-specific antibodies using a total IgG assay. The primary endpoints in Study 1 were the proportion of patients with a positive immune response (≥2-fold rise in IsdB-specific IgG antibody level) the geometric mean concentration (GMC), and the geometric mean-fold rise (GMFR), all from baseline at Day 14. The primary endpoint in Study 2 was the GMFR in IsdB-specific IgG antibody concentration from baseline at Day 14. In Study 1, 84.4% responded in the adjuvanted V710 group, and 71.9% in the non-adjuvanted V710 group. The GMC was 115.4 µg/mL in the adjuvanted group and 99.1 µg/mL in the nonadjuvanted group. The GMFR in antibody concentration in the group receiving aluminum-adjuvanted V710 was 4.5 and the GMFR in the group receiving non-adjuvanted V710 was 4.0. In Study 2, the GMFR in antibody concentration in the V710 group was 5.3, and 80.5% had a positive immune response. None responded in the placebo group. Positive immune response was seen in the active treatment groups over the full duration of each study. There were no serious adverse experiences (AE) in either study, and no patients discontinued due to an AE. There were no clinically meaningful differences in AEs between groups in either study. In conclusion, V710, both with and without aluminum adjuvant, and in both liquid and lyophilized formulations, was immunogenic within 14 days of vaccination. All treatments showed similar safety profiles.
Assuntos
Proteínas de Transporte de Cátions/imunologia , Infecções Estafilocócicas/prevenção & controle , Vacinas Antiestafilocócicas/imunologia , Adjuvantes Imunológicos/administração & dosagem , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Antibacterianos/sangue , Proteínas de Bactérias/imunologia , Método Duplo-Cego , Determinação de Ponto Final , Feminino , Liofilização , Humanos , Imunoglobulina G/sangue , Masculino , Pessoa de Meia-Idade , Vacinas Antiestafilocócicas/administração & dosagem , Vacinas Antiestafilocócicas/efeitos adversos , Adulto JovemRESUMO
To construct a universal vaccine against mastitis induced by either Streptococcus agalactiae or Staphylococcus aureus, the B cell epitopes of the surface immunogenic protein (Sip) from S. agalactiae and clumping factor A (ClfA) from S. aureus were analyzed and predicted. sip-clfA, a novel chimeric B cell epitope-based gene, was obtained by overlap PCR, and then the recombinant Sip-ClfA (rSip-ClfA) was expressed and purified. rSip-ClfA and inactivated S. agalactiae and S. aureus were formulated into different vaccines with mineral oil as the adjuvant and evaluated in mouse models. The rSip-ClfA vaccination induced immunoglobulin G (IgG) titers higher than those seen in groups immunized with inactivated bacteria. Furthermore, the response to rSip-ClfA immunization was characterized as having a dominant IgG1 subtype, whereas both bacterial immunizations produced similar levels of IgG1 and IgG2a. The antiserum capacities for opsonizing adhesion and phagocytosis were significantly greater in the rSip-ClfA immunization group than in the killed-bacterium immunization groups (P < 0.05). The immunized lactating mice were challenged with either S. agalactiae or S. aureus via the intramammary route. At 24 h postinfection, the numbers of bacteria recovered from the mammary glands in the rSip-ClfA group were >5-fold lower than those in both inactivated-bacterium groups (P < 0.01). Histopathological examination of the mammary glands showed that rSip-ClfA immunization provided better protection of mammary gland tissue integrity against both S. agalactiae and S. aureus challenges. Thus, the recombinant protein rSip-ClfA would be a promising vaccine candidate against mastitis induced by either S. agalactiae or S. aureus.
Assuntos
Epitopos de Linfócito B/imunologia , Mastite/prevenção & controle , Vacinas Antiestafilocócicas/imunologia , Staphylococcus aureus/imunologia , Streptococcus agalactiae/imunologia , Adjuvantes Imunológicos/administração & dosagem , Animais , Anticorpos Antibacterianos/sangue , Carga Bacteriana , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Bovinos , Coagulase/genética , Coagulase/imunologia , Epitopos de Linfócito B/genética , Feminino , Histocitoquímica , Imunoglobulina G/sangue , Glândulas Mamárias Animais/microbiologia , Mastite/imunologia , Mastite/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Óleo Mineral/administração & dosagem , Proteínas Opsonizantes/sangue , Fagocitose , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Vacinas Antiestafilocócicas/administração & dosagem , Vacinas Antiestafilocócicas/genética , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificação , Streptococcus agalactiae/genética , Streptococcus agalactiae/isolamento & purificação , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologiaRESUMO
Merck V710 is a novel vaccine containing the conserved Staphylococcus aureus iron surface determinant B shown to be protective in animal models. A phase I, multicenter, double-blind study of the dose range was conducted to assess the immunogenicity and safety of an adjuvanted liquid formulation of V710. A total of 124 adults (18 to 55 years of age) were randomized 1:1:1:1 to receive one 0.5-ml intramuscular injection of V710 (5 µg, 30 µg, or 90 µg) or saline placebo. A positive immune response was defined as at least a 2-fold increase in IsdB-specific IgG levels from baseline levels. Local and systemic adverse events were assessed for 5 and 14 days, respectively, following vaccination. Positive immune responses were detected in 12 (67%) of the 18 subjects in the groups receiving 30 and 90 µg V710 tested at day 10. At day 14, a significantly greater proportion of subjects manifested a positive immune response with higher geometric mean concentrations in the V710 30-µg (86%; geometric mean concentration of 116 µg/ml) and 90-µg (87%; geometric mean concentration of 131 µg/ml) dose groups than in the V710 5-µg (29%; geometric mean concentration of 51 µg/ml) or placebo (4%; geometric mean concentration of 23 µg/ml) groups. Immune responses were durable through day 84. Subjects <40 and ≥40 years of age had comparable immune responses. The most common adverse events were injection-site pain, nausea, fatigue, and headache, usually of mild intensity. No immediate reactions or serious adverse events were reported. In this first study of V710 in humans, a single 30-µg or 90-µg dose was more immunogenic than the 5-µg dose or placebo. Immune responses were evident by 10 to 14 days after vaccination in most responders.
Assuntos
Vacinas Antiestafilocócicas/efeitos adversos , Vacinas Antiestafilocócicas/imunologia , Adjuvantes Imunológicos/administração & dosagem , Adolescente , Adulto , Anticorpos Antibacterianos/sangue , Proteínas de Transporte de Cátions/imunologia , Método Duplo-Cego , Fadiga/induzido quimicamente , Feminino , Cefaleia/induzido quimicamente , Humanos , Imunoglobulina G/sangue , Injeções Intramusculares , Masculino , Pessoa de Meia-Idade , Náusea/induzido quimicamente , Dor/induzido quimicamente , Placebos/administração & dosagem , Vacinas Antiestafilocócicas/administração & dosagem , Staphylococcus aureus/imunologia , Adulto JovemRESUMO
The present study evaluated the potential of recombinant binding region A of clumping factor A (rClfA-A) to be an effective component of a vaccine against mastitis induced by Staphylococcus aureus in the mouse. rClfA-A and inactivated S. aureus were each emulsified in Freund's adjuvant, mineral oil adjuvant, and Seppic adjuvant; phosphate-buffered saline was used as a control. Seven groups of 12 mice each were immunized intraperitoneally three times at 2-week intervals. The titers of IgG and subtypes thereof (IgG1 and IgG2a) in the rClfA-A-immunized group were more than 1,000-fold higher than those in the killed-bacteria-immunized group (P < 0.01). Of the three adjuvants used, mineral oil adjuvant induced the highest antibody levels for both antigens (P < 0.001). Furthermore, the anti-rClfA-A antibody capacities for bacterial adhesion and opsonizing phagocytosis were significantly greater in the rClfA-A-immunized group than in the killed-bacteria-immunized group (P < 0.05). Lactating mice immunized with either rClfA-A or inactivated vaccine were challenged with S. aureus via the intramammary route. The numbers of bacteria recovered from the murine mammary glands 24 h after inoculation were significantly lower in the rClfA-A group than in the killed-bacteria-immunized group (P < 0.001). Histologic examination of the mammary glands showed that rClfA-A immunization effectively preserved tissue integrity. Thus, rClfA-A emulsified in an oil adjuvant provides strong immune protection against S. aureus-induced mastitis in the mouse.
Assuntos
Coagulase/imunologia , Mastite/prevenção & controle , Vacinas Antiestafilocócicas/imunologia , Adjuvantes Imunológicos/administração & dosagem , Animais , Anticorpos Antibacterianos/sangue , Aderência Bacteriana/imunologia , Carga Bacteriana , Coagulase/administração & dosagem , Modelos Animais de Doenças , Feminino , Adjuvante de Freund/administração & dosagem , Histocitoquímica , Imunoglobulina G/sangue , Injeções Intraperitoneais , Masculino , Glândulas Mamárias Animais/microbiologia , Glândulas Mamárias Animais/patologia , Mastite/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Microscopia , Proteínas Opsonizantes/sangue , Fagocitose/imunologia , Vacinas Antiestafilocócicas/administração & dosagem , Vacinas de Subunidades Antigênicas/imunologiaRESUMO
Antibiotic-resistant staphylococci are the leading cause of nosocomial infections in many hospitals around the world. Meanwhile, methicillin-resistant Staphylococcus aureus (MRSA) spread also in the community where highly virulent strains infect healthy adults that have no predisposing risk factors. Although a few novel antibiotics have been recently introduced into clinical practice, the search for alternative strategies to efficiently combat staphylococcal infections is urgently demanded to decrease the enormous burden caused by pathogenic staphylococci. In particular, immunological strategies based on vaccine development or therapeutic antibodies may significantly enhance the efficiency of anti-staphylococcal therapy. Most approaches are directed against surface components of staphylococci such as cell wall-linked adhesins, teichoic acids, capsule, the biofilm component PIA/PNAG, or soluble virulence determinants such as alpha-toxin, Panton-Valentine leukocidin, or superantigenic enterotoxins. Although 2 recent clinical trials have failed, several novel promising vaccines and therapeutic antibodies are currently in preclinical and clinical development.