RESUMO
Staphylococcus aureus is a significant bacterial pathogen in both community and hospital settings, and the escalation of antimicrobial-resistant strains is of immense global concern. Vaccination is an inviting long-term strategy to curb staphylococcal disease, but identification of an effective vaccine has proved to be challenging. Three well-characterized, ubiquitous, secreted immune evasion factors from the staphylococcal superantigen-like (SSL) protein family were selected for the development of a vaccine. Wild-type SSL3, 7 and 11, which inhibit signaling through Toll-like receptor 2, cleavage of complement component 5 and neutrophil function, respectively, were successfully combined into a stable, active fusion protein (PolySSL7311). Vaccination of mice with an attenuated form of the PolySSL7311 protein stimulated significantly elevated specific immunoglobulin G and splenocyte proliferation responses to each component relative to adjuvant-only controls. Vaccination with PolySSL7311, but not a mixture of the individual proteins, led to a > 102 reduction in S. aureus tissue burden compared with controls after peritoneal challenge. Comparable antibody responses were elicited after coadministration of the vaccine in either AddaVax (an analog of MF59) or an Alum-based adjuvant; but only AddaVax conferred a significant reduction in bacterial load, aligning with other studies that suggest both cellular and humoral immune responses are necessary for protective immunity to S. aureus. Anti-sera from mice immunized with PolySSL7311, but not individual proteins, partially neutralized the functional activities of SSL7. This study confirms the importance of these SSLs for the survival of S. aureus in vivo and suggests that PolySSL7311 is a promising vaccine candidate.
Assuntos
Proteínas de Bactérias , Infecções Estafilocócicas , Vacinas Antiestafilocócicas , Staphylococcus aureus , Superantígenos , Animais , Staphylococcus aureus/imunologia , Vacinas Antiestafilocócicas/imunologia , Superantígenos/imunologia , Infecções Estafilocócicas/imunologia , Infecções Estafilocócicas/prevenção & controle , Camundongos , Proteínas de Bactérias/imunologia , Anticorpos Antibacterianos/imunologia , Anticorpos Antibacterianos/sangue , Feminino , Proteínas Recombinantes de Fusão/imunologia , Imunoglobulina G/imunologia , Imunoglobulina G/sangue , Estudos de Viabilidade , Vacinação , Antígenos de Bactérias/imunologia , Camundongos Endogâmicos BALB C , Adjuvantes ImunológicosRESUMO
Tissue-resident memory T cells are important in adaptive immunity against many infections, rendering these cells attractive potential targets in vaccine development. Genetic and experimental evidence highlights the importance of cellular immunity in protection from Staphylococcus aureus skin infections, yet skin-resident memory T cells are, thus far, an untested component of immunity during such infections. Novel methods of generating and sampling vaccine-induced skin memory T cells are paralleled by discoveries of global, skin-wide immunosurveillance. We propose skin-resident memory CD4+ T cells as a potential missing link in the search for correlates of protection during S. aureus infections. A better appreciation of their phenotypes and functions could accelerate the development of preventive vaccines against this highly virulent and antibiotic-resistant pathogen.
Assuntos
Linfócitos T CD4-Positivos , Memória Imunológica , Pele , Infecções Estafilocócicas , Staphylococcus aureus , Animais , Linfócitos T CD4-Positivos/imunologia , Humanos , Camundongos , Pele/citologia , Pele/imunologia , Infecções Estafilocócicas/terapia , Vacinas Antiestafilocócicas , VacinaçãoRESUMO
Vaccines against Staphylococcus aureus have eluded researchers for >3 decades while the burden of staphylococcal diseases has increased. Early vaccine attempts mainly used rodents to characterize preclinical efficacy, and all subsequently failed in human clinical efficacy trials. More recently, leukocidin AB (LukAB) has gained interest as a vaccine antigen. We developed a minipig deep surgical wound infection model offering 3 independent efficacy readouts: bacterial load at the superficial and at the deep-seated surgical site, and dissemination of bacteria. Due to similarities with humans, minipigs are an attractive option to study novel vaccine candidates. With this model, we characterized the efficacy of a LukAB toxoid as vaccine candidate. Compared to control animals, a 3-log reduction of bacteria at the deep-seated surgical site was observed in LukAB-treated minipigs and dissemination of bacteria was dramatically reduced. Therefore, LukAB toxoids may be a useful addition to S. aureus vaccines and warrant further study.
Assuntos
Infecções Estafilocócicas , Vacinas Antiestafilocócicas , Animais , Carga Bacteriana , Proteínas de Bactérias , Leucocidinas , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus , Infecção da Ferida Cirúrgica/prevenção & controle , Suínos , Porco Miniatura , VacinaçãoRESUMO
Staphylococcus aureus (S. aureus) is one of the most common bacterial infections worldwide, and antibiotic resistant strains such as Methicillin-Resistant S. aureus (MRSA) are a major threat and burden to public health. MRSA not only infects immunocompromised patients but also healthy individuals and has rapidly spread from the healthcare setting to the outside community. However, all vaccines tested in clinical trials to date have failed. Immunocompromised individuals such as patients with HIV or decreased levels of CD4+ T cells are highly susceptible to S. aureus infections, and they are also at increased risk of developing fungal infections. We therefore wondered whether stimulation of antifungal immunity might promote the type of immune responses needed for effective host defense against S. aureus. Here we show that vaccination of mice with a fungal ß-glucan particle (GP) loaded with S. aureus antigens provides protective immunity to S. aureus. We generated glucan particles loaded with the four S. aureus proteins ClfA, IsdA, MntC, and SdrE, creating the 4X-SA-GP vaccine. Vaccination of mice with three doses of 4X-SA-GP promoted protection in a systemic model of S. aureus infection with a significant reduction in the bacterial burden in the spleen and kidneys. 4X-SA-GP vaccination induced antigen-specific Th1 and Th17 CD4+ T cell and antibody responses and provided long-term protection. This work suggests that the GP vaccine system has potential as a novel approach to developing vaccines for S. aureus.
Assuntos
Saccharomyces cerevisiae/imunologia , Infecções Estafilocócicas/imunologia , Vacinas Antiestafilocócicas/imunologia , Staphylococcus aureus/imunologia , Animais , Anticorpos Antibacterianos/imunologia , Coagulase/administração & dosagem , Coagulase/genética , Coagulase/imunologia , Feminino , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Saccharomyces cerevisiae/química , Infecções Estafilocócicas/microbiologia , Vacinas Antiestafilocócicas/administração & dosagem , Vacinas Antiestafilocócicas/genética , Staphylococcus aureus/genética , Células Th1/imunologia , Células Th17/imunologia , Vacinação , beta-Glucanas/administração & dosagem , beta-Glucanas/imunologiaRESUMO
AIMS: Staphylococcus aureus is an opportunistic pathogen of humans. No commercial vaccine is available to combat S. aureus infections. In this study, we have investigated the protective immune response generated by S. aureus non-covalently associated cell wall surface protein N-acetylmuramoyl-L-alanine amidase (AM) in combination with Alum (Al) and heat-killed S. aureus (hkSA) using murine models. METHODS AND RESULTS: BALB/c mice were immunized with increasing concentrations of AM antigen or hkSA to determine their optimum concentration for vaccination. Fifty micrograms of AM and hkSA each were found to generate maximum anti-AM IgG antibody production. BALB/c mice were immunized next with 50 µg of AM, 50 µg of hKSA and 1 mg Al vaccine formulation. Vaccine efficacy was validated by challenging immunized BALB/c mice with S. aureus Newman and three clinical methicillin-resistant S. aureus strains. AM-hkSA-Al-immunized mice generated high anti-AM IgG antibody response with IgG1 and IgG2b as the predominant immunoglobulin subtypes. Increased survival (60%-90%) with decreased clinical disease symptoms was observed in the vaccinated BALB/c mice group. A significantly lower bacterial load and decreased kidney abscess formation was observed following the challenge with S. aureus in the vaccinated BALB/c mice group. Furthermore, the efficacy of AM-hkSA-Al vaccine was also validated using C57 BL/6 and Swiss albino mice. CONCLUSIONS: Using murine infection models, we have demonstrated that AM-hkSA-Al vaccine would be effective in preventing S. aureus infections. SIGNIFICANCE AND IMPACT OF STUDY: AM-hkSA-Al vaccine elicited strong immune response and may be considered for future vaccine design against S. aureus infections.
Assuntos
Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Vacinas Antiestafilocócicas , Vacinas , Compostos de Alúmen , Amidoidrolases , Animais , Anticorpos Antibacterianos , Camundongos , Camundongos Endogâmicos BALB C , Infecções Estafilocócicas/prevenção & controle , Staphylococcus aureus , Eficácia de VacinasRESUMO
The main purpose of this review is to present justification for the urgent need to implement specific prophylaxis of invasive Staphylococcus aureus infections. We emphasize the difficulties in achieving this goal due to numerous S. aureus virulence factors important for the process of infection and the remarkable ability of these bacteria to avoid host defense mechanisms. We precede these considerations with a brief overview of the global necessitiy to intensify the use of vaccines against other pathogens as well, particularly in light of an impasse in antibiotic therapy. Finally, we point out global trends in research into modern technologies used in the field of molecular microbiology to develop new vaccines. We focus on the vaccines designed to fight the infections caused by S. aureus, which are often resistant to the majority of available therapeutic options.
Assuntos
Infecções Estafilocócicas/prevenção & controle , Vacinas Antiestafilocócicas/uso terapêutico , Staphylococcus aureus/imunologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Humanos , Infecções Estafilocócicas/imunologia , Vacinas Antiestafilocócicas/imunologia , Vacinas Antiestafilocócicas/farmacologia , Staphylococcus aureus/genética , Staphylococcus aureus/patogenicidade , Desenvolvimento de Vacinas , Fatores de Virulência/genética , Fatores de Virulência/imunologiaRESUMO
Staphylococcus aureus is an important human opportunistic pathogen that can have a major influence on public health. Here, we aimed to evaluate different aspects of the immune response to a novel multi-epitope fusion protein (HMS) based on HlaH35L, MntC, and SACOL0723 proteins in comparison to the individual antigens. For this purpose, specific total IgG, IgG1, and IgG2a isotypes and the cytokines related to Th1, Th2, and Th17 were assessed. The Bio-efficiency of the fusion protein was evaluated by opsonic killing activity. The HMS fusion protein elicited a high specific IgG level and also induced a higher level of Th1, Th2, and Th17-related cytokines which were more polarized towards the Th1 and Th17 compared to individual antigens. The HMS-specific antisera also significantly promoted phagocytosis of S. aureus COL strain by mouse macrophages. In conclusion, the fusion protein might be an effective vaccine for potential protective immunity against a lethal infection of S. aureus in mice.
Assuntos
Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas/prevenção & controle , Vacinas Antiestafilocócicas/imunologia , Animais , Anticorpos Antibacterianos/imunologia , Citocinas/imunologia , Epitopos/imunologia , Imunoglobulina G/imunologia , Staphylococcus aureus Resistente à Meticilina/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Infecções Estafilocócicas/imunologia , Linfócitos T/imunologiaRESUMO
Unbiased identification of individual immunogenic B-cell epitopes in major antigens of a pathogen remains a technology challenge for vaccine discovery. We therefore developed a platform for rapid phage display screening of deep recombinant libraries consisting of as few as one major pathogen antigen. Using the bicomponent pore-forming leukocidin (Luk) exotoxins of the major pathogen Staphylococcus aureus as a prototype, we randomly fragmented and separately ligated the hemolysin gamma A (HlgA) and LukS genes into a custom-built phage display system, termed pComb-Opti8. Deep sequence analysis of barcoded amplimers of the HlgA and LukS gene fragment libraries demonstrated that biopannng against a cross-reactive anti-Luk monoclonal antibody (MAb) recovered convergent molecular clones with short overlapping homologous sequences. We thereby identified an 11-amino-acid sequence that is highly conserved in four Luk toxin subunits and is ubiquitous in representation within S. aureus clinical isolates. The isolated 11-amino-acid peptide probe was predicted to retain the native three-dimensional (3D) conformation seen within the Luk holotoxin. Indeed, this peptide was recognized by the selecting anti-Luk MAb, and, using mutated peptides, we showed that a particular amino acid side chain was essential for these interactions. Furthermore, murine immunization with this peptide elicited IgG responses that were highly reactive with both the autologous synthetic peptide and the full-length Luk toxin homologues. Thus, using a gene fragment- and phage display-based pipeline, we have identified and validated immunogenic B-cell epitopes that are cross-reactive between members of the pore-forming leukocidin family. This approach could be harnessed to identify novel epitopes for a much-needed S. aureus-protective subunit vaccine.
Assuntos
Proteínas de Bactérias/imunologia , Mapeamento de Epitopos , Epitopos de Linfócito B/imunologia , Exotoxinas/imunologia , Staphylococcus aureus/imunologia , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Antibacterianos/imunologia , Anticorpos Monoclonais/imunologia , Imunoglobulina G/sangue , Camundongos , Biblioteca de Peptídeos , Vacinas Antiestafilocócicas/administração & dosagem , Vacinas Antiestafilocócicas/imunologia , Vacinas de Subunidades Antigênicas/administração & dosagem , Vacinas de Subunidades Antigênicas/imunologia , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/imunologiaRESUMO
Most pathogens initiate infection via the mucosa, therefore delivery of vaccines directly to the mucosa is likely to be advantageous for stimulating protective immunity at the site of entry. PilVax is a novel mucosal vaccine platform that harnesses Lactococcus lactis bacteria engineered to stably express multiple copies of vaccine peptide antigens within pili, hair-like structures which extend from the cell wall. This strategy elicited systemic and mucosal antibody responses to a model antigen after intranasal immunization, but has not been tested for its capacity to stimulate protective mucosal immunity. A well-characterized linear B-cell epitope, D3(22-33) , from the fibronectin-binding protein A of Staphylococcus aureus was successfully introduced into PilVax and delivered intranasally to mice. Specific antipeptide immunoglobulin (Ig) G and IgA antibodies were detected in the serum and respiratory mucosa of vaccinated mice. Responses to the major pilus backbone protein Spy0128 were also assessed; robust antibody responses to this antigen were generated both systemically and in the respiratory and intestinal mucosa. Mice were challenged intranasally with the mouse-adapted S. aureus JSNZ strain and the S. aureus load quantified 7 days after challenge. Unexpectedly, exposure to PilVax, irrespective of the presence of the peptide, resulted in a significant reduction in S. aureus load in both the intestine and nasal mucosa (both P < 0.05) when compared with unvaccinated control mice. The mechanism(s) of protection are unclear, but merit further investigation to determine whether PilVax is a suitable platform for delivery of vaccine candidate antigens to the mucosa.
Assuntos
Imunidade nas Mucosas , Lactococcus lactis , Vacinas Antiestafilocócicas/imunologia , Administração Intranasal , Animais , Anticorpos Antibacterianos/sangue , Carga Bacteriana , Epitopos de Linfócito B/imunologia , Intestinos/microbiologia , Lactococcus lactis/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Mucosa Nasal/microbiologia , Staphylococcus aureusRESUMO
Staphylococcus aureus is one of the pathogens most frequently isolated from cases of mastitis worldwide. To decrease the effect of S. aureus mastitis in dairy farming, alternative strategies for controlling mastitis are needed that depend on a better knowledge of cow-to-cow variations in S. aureus antibody production. The present study sought to explore the diversity of S. aureus antibodies produced by dairy cows with a distinct mastitis history and vaccinated with a polyvalent mastitis vaccine. We obtained protein extracts from S. aureus isolates derived from persistent subclinical mastitis. Proteins were fractionated using 2-dimensional gel electrophoresis and Western blotting. Then, Western blotting membranes were exposed to sera from 24 dairy cows that had been divided into the following groups: vaccinated dairy cows that were infected with S. aureus, further subdivided according to whether they (a) remained infected by S. aureus or (b) recovered from the intramammary infection; unvaccinated dairy cows infected with S. aureus; and vaccinated healthy dairy cows with no history of S. aureus mastitis. Proteins found to be reactive by Western blot were identified by mass spectrometry (MALDI/TOF-TOF). Our most important finding was that F0F1 ATP synthase subunit α, succinyl-diaminopimelate desuccinylase, and cysteinyl-tRNA synthetase were potential candidate proteins for the prevention of S. aureus mastitis. This study strengthens the notion that variations among animals should not be ignored and shows that the heterogeneity of antibody production against anti-staphylococcal antigens in animals may enable the identification of new immunotherapy targets.
Assuntos
Anticorpos Antibacterianos/sangue , Mastite Bovina/imunologia , Infecções Estafilocócicas/veterinária , Vacinas Antiestafilocócicas/administração & dosagem , Staphylococcus aureus/imunologia , Animais , Anticorpos Antibacterianos/imunologia , Bovinos , Feminino , Humanos , Mastite Bovina/microbiologia , Mastite Bovina/prevenção & controle , Leite , Infecções Estafilocócicas/imunologia , Infecções Estafilocócicas/microbiologia , Vacinas Antiestafilocócicas/imunologiaRESUMO
Staphylococcus aureus is a causative agent of chronic biofilm-associated infections that are recalcitrant to resolution by the immune system or antibiotics. To combat these infections, an antistaphylococcal, biofilm-specific quadrivalent vaccine against an osteomyelitis model in rabbits has previously been developed and shown to be effective at eliminating biofilm-embedded bacterial populations. However, the addition of antibiotics was required to eradicate remaining planktonic populations. In this study, a planktonic upregulated antigen was combined with the quadrivalent vaccine to remove the need for antibiotic therapy. Immunization with this pentavalent vaccine followed by intraperitoneal challenge of BALB/c mice with S. aureus resulted in 16.7% and 91.7% mortality in pentavalent vaccine and control groups, respectively (P < 0.001). Complete bacterial elimination was found in 66.7% of the pentavalent cohort, while only 8.3% of the control animals cleared the infection (P < 0.05). Further protective efficacy was observed in immunized rabbits following intramedullary challenge with S. aureus, where 62.5% of the pentavalent cohort completely cleared the infection, versus none of the control animals (P < 0.05). Passive immunization of BALB/c mice with serum IgG against the vaccine antigens prior to intraperitoneal challenge with S. aureus prevented mortality in 100% of mice and eliminated bacteria in 33.3% of the challenged mice. These results demonstrate that targeting both the planktonic and biofilm stages with the pentavalent vaccine or the IgG elicited by immunization can effectively protect against S. aureus infection.
Assuntos
Antígenos de Bactérias/imunologia , Infecções Estafilocócicas/imunologia , Infecções Estafilocócicas/prevenção & controle , Vacinas Antiestafilocócicas/imunologia , Staphylococcus aureus/imunologia , Animais , Anticorpos Antibacterianos/administração & dosagem , Anticorpos Antibacterianos/imunologia , Modelos Animais de Doenças , Imunização Passiva , Imunoglobulina G/administração & dosagem , Imunoglobulina G/imunologia , Camundongos Endogâmicos BALB C , Coelhos , Vacinas Antiestafilocócicas/administração & dosagem , Análise de Sobrevida , Resultado do TratamentoRESUMO
Development of long-term memory is crucial for vaccine-induced adaptive immunity against infectious diseases such as Staphylococcus aureus infection. Toxic shock syndrome toxin 1 (TSST-1), one of the superantigens produced by S. aureus, is a possible vaccine candidate against infectious diseases caused by this pathogen. We previously reported that vaccination with less toxic mutant TSST-1 (mTSST-1) induced T helper 17 (Th17) cells and elicited interleukin-17A (IL-17A)-mediated protection against S. aureus infection 1 week after vaccination. In the present study, we investigated the host immune response induced by mTSST-1 vaccination in the memory phase, 12 weeks after the final vaccination. The protective effect and IL-17A production after vaccination with mTSST-1 were eliminated because of IL-10 production. In the presence of IL-10-neutralizing monoclonal antibody (mAb), IL-17A production was restored in culture supernatants of CD4+ T cells and macrophages sorted from the spleens of vaccinated mice. Vaccinated mice treated with anti-IL-10 mAb were protected against systemic S. aureus infection in the memory phase. From these results, it was suggested that IL-10 produced in the memory phase suppresses the IL-17A-dependent vaccine effect through downregulation of IL-17A production.
Assuntos
Toxinas Bacterianas/genética , Enterotoxinas/genética , Interleucina-10/genética , Interleucina-17/genética , Infecções Estafilocócicas/prevenção & controle , Vacinas Antiestafilocócicas/genética , Staphylococcus aureus/efeitos dos fármacos , Superantígenos/genética , Células Th17/efeitos dos fármacos , Animais , Anticorpos Neutralizantes/farmacologia , Toxinas Bacterianas/administração & dosagem , Toxinas Bacterianas/biossíntese , Clonagem Molecular , Enterotoxinas/administração & dosagem , Enterotoxinas/biossíntese , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Memória Imunológica/efeitos dos fármacos , Interleucina-10/antagonistas & inibidores , Interleucina-10/imunologia , Interleucina-17/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética , Infecções Estafilocócicas/imunologia , Infecções Estafilocócicas/microbiologia , Vacinas Antiestafilocócicas/administração & dosagem , Vacinas Antiestafilocócicas/biossíntese , Staphylococcus aureus/imunologia , Staphylococcus aureus/patogenicidade , Superantígenos/administração & dosagem , Superantígenos/biossíntese , Células Th17/imunologia , Vacinação , Vacinas SintéticasRESUMO
Staphylococcus aureus bloodstream infection can have potentially catastrophic consequences for patients on hemodialysis. Consequently, an effective vaccine to prevent S aureus infection would have a significant influence on morbidity and mortality in this group. To date, however, efforts to develop a vaccine have been unsuccessful. Previous antibody-inducing vaccine candidates did not prevent or attenuate S aureus infection in clinical trials. Recent advances have helped to elucidate the role of specific T-cell subsets, notably T-helper cell 1 and T-helper cell 17, in the immune response to S aureus. These cells are essential for coordinating an effective phagocytic response via cytokine production, indirectly leading to destruction of the organism. It is now widely accepted that next-generation S aureus vaccines must also induce effective T-cell-mediated immunity. However, there remains a gap in our knowledge: how will an S aureus vaccine drive these responses in those patients most at risk? Given that patients on hemodialysis are an immunocompromised population, in particular with specific T-cell defects, including defects in T-helper cell subsets, this is likely to affect their ability to respond to an S aureus vaccine. We urgently need a better understanding of T-cell-mediated immunity in this cohort if an efficacious vaccine is ever to be realized for these patients.
Assuntos
Falência Renal Crônica/terapia , Diálise Renal/efeitos adversos , Infecções Estafilocócicas/prevenção & controle , Vacinas Antiestafilocócicas/uso terapêutico , Staphylococcus aureus/imunologia , Animais , Ensaios Clínicos como Assunto , Análise Custo-Benefício , Modelos Animais de Doenças , Humanos , Imunidade Celular , Falência Renal Crônica/imunologia , Infecções Estafilocócicas/economia , Infecções Estafilocócicas/etiologia , Vacinas Antiestafilocócicas/economia , Linfócitos T Auxiliares-Indutores/imunologia , Resultado do Tratamento , Vacinação/métodosRESUMO
The purpose of this investigation was to construct a recombinant Escherichia coli strain displaying the Staphylococcus aureus target of RNAIII activating protein (TRAP) on its surface, and to investigate the strain for its immunogenicity. The lpp'ompA and lpp'ompA-TRAP genes were fused by the overlap polymerase chain reaction and then ligated into expression plasmid pQE30 producing pLO and pLO-TRAP. These two recombinant plasmids were transformed into E. coli XL1-Blue, resulting in XL1-Blue/pLO and XL1-Blue/pLO-TRAP, which were induced to express protein. The expressed TRAP protein was displayed on the surface of XL1-Blue as judged by whole cell ELISA, flow cytometric analysis, and laser scanning confocal microscopy using the lpp'ompA surface display system. ICR mice were intramuscularly immunized with recombinant strains XL1-Blue/pLO and XL1-Blue/pLO-TRAP as well as recombinant protein TRAP. Immunized mice were assessed for anti-TRAP antibody and lymphocytes for secreted IL-4 and IFN-γ by ELISPOT and secreted IL-17A by indirect ELISA. Immunized mice were challenged with S. aureus Newman and HLJ23-1 strains. The results showed both XL1-Blue/pLO-TRAP and TRAP protein immunized mice to produce better cellular and humoral immunity than XL1-Blue/pLO and PBS injected mice.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/imunologia , Proteínas da Membrana Bacteriana Externa/imunologia , Proteínas de Bactérias/imunologia , Técnicas de Visualização da Superfície Celular , Proteínas de Membrana/imunologia , Proteínas Recombinantes de Fusão/imunologia , Infecções Estafilocócicas/prevenção & controle , Vacinas Antiestafilocócicas/imunologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Anticorpos Antibacterianos/sangue , Proteínas da Membrana Bacteriana Externa/genética , Proteínas de Bactérias/genética , Citocinas/metabolismo , Modelos Animais de Doenças , Portadores de Fármacos , ELISPOT , Escherichia coli/genética , Escherichia coli/metabolismo , Injeções Intramusculares , Linfócitos/imunologia , Proteínas de Membrana/genética , Camundongos Endogâmicos ICR , Proteínas Recombinantes de Fusão/genética , Vacinas Antiestafilocócicas/administração & dosagem , Vacinas Antiestafilocócicas/genéticaRESUMO
Bacteria can cause life-threatening infections, such as pneumonia, meningitis, or sepsis. Antibiotic therapy is a mainstay of treatment, although antimicrobial resistance has drastically increased over the years. Unfortunately, safe and effective vaccines against most pathogens have not yet been approved, and thus developing alternative treatments is important. We analyzed the efficiency of factor H (FH)6-7/Fc, a novel antibacterial immunotherapeutic protein against the Gram-positive bacterium Streptococcus pyogenes This protein is composed of two domains of complement inhibitor human FH (FH complement control protein modules 6 and 7) that bind to S. pyogenes, linked to the Fc region of IgG (FH6-7/Fc). FH6-7/Fc has previously been shown to enhance complement-dependent killing of, and facilitate bacterial clearance in, animal models of the Gram-negative pathogens Haemophilus influenzae and Neisseria meningitidis We hypothesized that activation of complement by FH6-7/Fc on the surface of Gram-positive bacteria such as S. pyogenes will enable professional phagocytes to eliminate the pathogen. We found that FH6-7/Fc alleviated S. pyogenes-induced sepsis in a transgenic mouse model expressing human FH (S. pyogenes binds FH in a human-specific manner). Furthermore, FH6-7/Fc, which binds to protein H and selected M proteins, displaced FH from the bacterial surface, enhanced alternative pathway activation, and reduced bacterial blood burden by opsonophagocytosis in a C3-dependent manner in an ex vivo human whole-blood model. In conclusion, FH-Fc chimeric proteins could serve as adjunctive treatments against multidrug-resistant bacterial infections.
Assuntos
Fator H do Complemento/uso terapêutico , Imunoterapia/métodos , Proteínas Recombinantes de Fusão/uso terapêutico , Sepse/terapia , Vacinas Antiestafilocócicas/imunologia , Infecções Estreptocócicas/terapia , Streptococcus pyogenes/imunologia , Animais , Antibacterianos/uso terapêutico , Células Cultivadas , Complemento C3/metabolismo , C3 Convertase da Via Alternativa do Complemento , Fator H do Complemento/genética , Resistência a Múltiplos Medicamentos , Humanos , Camundongos , Camundongos Transgênicos , Fagocitose , Proteínas Recombinantes de Fusão/genética , Sepse/imunologia , Infecções Estreptocócicas/imunologiaRESUMO
BACKGROUND: Staphylococcus aureus, a leading cause of mastitis in dairy cattle, causes severe mastitis and/or chronic persistent infections with detrimental effects on the cows' wellbeing, lifespan and milk production. Despite years of research there is no effective vaccine against S. aureus mastitis. Boosting of non-protective pre-existing immunity to S. aureus, induced by natural exposure to S. aureus, by vaccination may interfere with vaccine efficacy. The aim was to assess whether experimental immunization of S. aureus naïve animals results in an immune response that differs from immunity following natural exposure to S. aureus. RESULTS: First, to define the period during which calves are immunologically naïve for S. aureus, Efb, LukM, and whole-cell S. aureus specific serum antibodies were measured in a cohort of newborn calves by ELISA. Rising S. aureus specific antibodies indicated that from week 12 onward calves mounted an immune response to S. aureus due to natural exposure. Next, an experimental immunization trial was set up using 8-week-old heifer calves (n = 16), half of which were immunized with the immune evasion molecules Efb and LukM. Immunization was repeated after one year and before parturition and humoral and cellular immunity specific for Efb and LukM was determined throughout the study. Post-partum, antibody levels against LukM and EfB were significantly higher in serum, colostrum and milk in the experimentally immunized animals compared to animals naturally exposed to S. aureus. LukM specific IL17a responses were also significantly higher in the immunized cows post-partum. CONCLUSIONS: Experimental immunization with staphylococcal immune evasion molecules starting before natural exposure resulted in significantly higher antibody levels against Efb and LukM around parturition in serum as well as the site of infection, i.e. in colostrum and milk, compared to natural exposure to S. aureus. This study showed that it is practically feasible to vaccinate S. aureus naïve cattle and that experimental immunization induced a humoral immune response that differed from that after natural exposure only.
Assuntos
Anticorpos Antibacterianos/imunologia , Proteínas de Bactérias/imunologia , Doenças dos Bovinos/prevenção & controle , Imunidade Humoral/imunologia , Leite/imunologia , Infecções Estafilocócicas/veterinária , Vacinas Antiestafilocócicas/uso terapêutico , Staphylococcus aureus/imunologia , Animais , Anticorpos Antibacterianos/sangue , Bovinos , Doenças dos Bovinos/imunologia , Doenças dos Bovinos/microbiologia , Feminino , Evasão da Resposta Imune/imunologia , Imunização/veterinária , Infecções Estafilocócicas/imunologia , Infecções Estafilocócicas/prevenção & controleRESUMO
Bovine mastitis affects animal health and welfare and milk production and quality, and it challenges the economic success of dairy farms. Staphylococcus aureus is one of the most commonly found pathogens in clinical mastitis but it also causes subclinical, persistent, and difficult-to-treat intramammary infections. Because of the failure of conventional antibiotic treatments and increasing pressure and concern from experts and consumers over the use of antibiotics in the dairy industry, many attempts have been made over the years to develop a vaccine for the prevention and control of Staph. aureus intramammary infections. Still, no commercially available vaccine formulation demonstrates sufficient protection and cost-effective potential. Multiple factors account for the lack of protection, including inadequate vaccine targets, high diversity among mastitis-provoking strains, cow-to-cow variation in immune response, and a failure to elicit an immune response that is appropriate for protection against a highly complex pathogen. The purpose of this review is to summarize key concepts related to the pathogenesis of Staph. aureus, and its interaction with the host, as well as to describe recent vaccine development strategies for prevention and control of Staph. aureus mastitis.
Assuntos
Antibacterianos/uso terapêutico , Mastite Bovina/prevenção & controle , Infecções Estafilocócicas/veterinária , Vacinas Antiestafilocócicas/imunologia , Staphylococcus aureus/imunologia , Animais , Bovinos , Indústria de Laticínios , Feminino , Interações Hospedeiro-Patógeno , Mastite Bovina/tratamento farmacológico , Mastite Bovina/microbiologia , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/prevenção & controle , Staphylococcus aureus/genética , Staphylococcus aureus/patogenicidadeRESUMO
Staphylococci have been isolated from various sites of the body of healthy sheep, as well as from many infections of those animals, the main one being mastitis. The objective of this review is to appraise the importance and significance of staphylococci in causing mastitis in ewes. The review includes a brief classification and taxonomy of staphylococci and describes the procedures for their isolation and identification, as well as their virulence determinants and the mechanisms of resistance to antibacterial agents. Various staphylococcal species have been implicated in staphylococcal mastitis and the characteristics of isolates are discussed with regards to potential virulence factors. Staphylococcal mastitis is explicitly described, with reference to sources of infection, the course of the disease and the relevant control measures. Finally, the potential significance of staphylococci present in ewes' milk for public health is discussed briefly.
Assuntos
Mastite/veterinária , Doenças dos Ovinos/microbiologia , Infecções Estafilocócicas/veterinária , Staphylococcus/isolamento & purificação , Animais , Farmacorresistência Bacteriana , Feminino , Microbiologia de Alimentos , Glândulas Mamárias Animais/microbiologia , Mastite/microbiologia , Leite/microbiologia , Ovinos , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/prevenção & controle , Vacinas Antiestafilocócicas , Staphylococcus/classificação , Staphylococcus/efeitos dos fármacos , Fatores de VirulênciaRESUMO
Mastitis is the inflammation of the mammary gland due to microbial infiltration causing a reduced mammary function. This study aims at developing a vaccine using Malaysian local isolate of Staphylococcus aureus and evaluating serum amyloid A, Interleukin-10, IgM and IgG responses periodically. Four bacterin concentrations (106, 107, 108 and 109 cfu/ml of the local isolate of S. aureus) were adjuvanted with aluminium potassium sulphate. Thirty cows grouped into 4 treatment groups (G-) were vaccinated (2 ml) intramuscularly, with a fifth G-A as control. The mean concentration (MC) of serum amyloid A (SAA) was significantly different (sig-d) (p Ë 0.05) in G-D at 0 h post vaccination (PV), 3 h PV, 24 h PV, weeks 1, 2, 3 and 4 PV (6-, 15-, 5-, 12-, 11-, 4- and 11-fold increased (FI) respectively). The MC of serum amyloid A was also sig-d in G-E at 0 h PV, weeks 1, 2 and 4 PV (3, 8, 5 and 8 FI respectively). The MC of IL-10 was sig-d in G-D and C at 3 h PV and week 2 PV (5 and 2 FI respectively). The IgM MC was sig-d in G-B and C at 3 h PV (5 and 6 FI respectively), at 24 h PV (5 and 9 FI respectively), at week 3 PV(2 and 2 FI respectively) and week 4 PV (3 and 4 FI respectively). The MC of IgG was sig-d in G-E at 0 h, 3 h and week 3 PV(5, 6 and 2 FI respectively) and in G-D at weeks 1-4 (3, 3, 3 and 5 FI respectively). In conclusion, elevated levels of SAA, IgG and IL-10 in G-D(108) informed our choice of best dosage which can be used to evoke immunity in cows.
Assuntos
Mastite Bovina/prevenção & controle , Vacinas Antiestafilocócicas/uso terapêutico , Staphylococcus aureus/imunologia , Animais , Anticorpos Antibacterianos/sangue , Bovinos , Feminino , Imunoglobulina G/sangue , Injeções Intramusculares/veterinária , Leite/microbiologia , Distribuição Aleatória , Proteína Amiloide A Sérica/metabolismo , Infecções Estafilocócicas/prevenção & controle , Infecções Estafilocócicas/veterinária , Vacinas Antiestafilocócicas/administração & dosagem , Vacinação/veterináriaRESUMO
Staphylococcus aureus wound infections delay healing and result in invasive complications such as osteomyelitis, especially in the setting of diabetic foot ulcers. In preclinical animal models of S. aureus skin infection, antibody neutralization of alpha-toxin (AT), an S. aureus-secreted pore-forming cytolytic toxin, reduces disease severity by inhibiting skin necrosis and restoring effective host immune responses. However, whether therapeutic neutralization of alpha-toxin is effective against S. aureus-infected wounds is unclear. Herein, the efficacy of prophylactic treatment with a human neutralizing anti-AT monoclonal antibody (MAb) was evaluated in an S. aureus skin wound infection model in nondiabetic and diabetic mice. In both nondiabetic and diabetic mice, anti-AT MAb treatment decreased wound size and bacterial burden and enhanced reepithelialization and wound resolution compared to control MAb treatment. Anti-AT MAb had distinctive effects on the host immune response, including decreased neutrophil and increased monocyte and macrophage infiltrates in nondiabetic mice and decreased neutrophil extracellular traps (NETs) in diabetic mice. Similar therapeutic efficacy was achieved with an active vaccine targeting AT. Taken together, neutralization of AT had a therapeutic effect against S. aureus-infected wounds in both nondiabetic and diabetic mice that was associated with differential effects on the host immune response.