ABSTRACT
Development of a vaccine against gonorrhoea is a global priority, driven by the rise in antibiotic resistance. Although Neisseria gonorrhoeae (Ng) infection does not induce substantial protective immunity, highly exposed individuals may develop immunity against re-infection with the same strain. Retrospective epidemiological studies have shown that vaccines containing Neisseria meningitidis (Nm) outer membrane vesicles (OMVs) provide a degree of cross-protection against Ng infection. We conducted a clinical trial (NCT04297436) of 4CMenB (Bexsero, GSK), a licensed Nm vaccine containing OMVs and recombinant antigens, comprising a single arm, open label study of two doses with 50 adults in coastal Kenya who have high exposure to Ng. Data from a Ng antigen microarray established that serum IgG and IgA reactivities against the gonococcal homologs of the recombinant antigens in the vaccine peaked at 10 but had declined by 24 weeks. For most reactive OMV-derived antigens, the reverse was the case. A cohort of similar individuals with laboratory-confirmed gonococcal infection were compared before, during, and after infection: their reactivities were weaker and differed from the vaccinated cohort. We conclude that the cross-protection of the 4CMenB vaccine against gonorrhoea could be explained by cross-reaction against a diverse selection of antigens derived from the OMV component.
Subject(s)
Antibodies, Bacterial , Gonorrhea , Immunoglobulin A , Immunoglobulin G , Neisseria gonorrhoeae , Vaccination , Humans , Gonorrhea/immunology , Gonorrhea/prevention & control , Neisseria gonorrhoeae/immunology , Adult , Immunoglobulin A/immunology , Immunoglobulin A/blood , Immunoglobulin G/blood , Immunoglobulin G/immunology , Male , Female , Antibodies, Bacterial/immunology , Antibodies, Bacterial/blood , Kenya/epidemiology , Meningococcal Vaccines/immunology , Meningococcal Vaccines/administration & dosage , Young Adult , Antigens, Bacterial/immunology , Neisseria meningitidis/immunology , Antibody Formation/immunology , Cross Protection/immunology , Middle AgedABSTRACT
Meningococcal (Neisseria meningitidis) serogroup B (MenB) strain antigens are diverse and a limited number of strains can be evaluated using the human serum bactericidal antibody (hSBA) assay. The genetic Meningococcal Antigen Typing System (gMATS) was developed to predict the likelihood of coverage for large numbers of isolates by the 4CMenB vaccine, which includes antigens Neisseria adhesin A (NadA), Neisserial Heparin-Binding Antigen (NHBA), factor H-binding protein (fHbp), and Porin A (PorA). In this study, we characterized by whole-genome analyses 284 invasive MenB isolates collected from 2010 to 2014 by the Argentinian National Laboratories Network (52-61 isolates per year). Strain coverage was estimated by gMATS on all isolates and by hSBA assay on 74 randomly selected isolates, representative of the whole panel. The four most common clonal complexes (CCs), accounting for 81.3% of isolates, were CC-865 (75 isolates, 26.4%), CC-32 (59, 20.8%), CC-35 (59, 20.8%), and CC-41/44 (38, 13.4%). Vaccine antigen genotyping showed diversity. The most prevalent variants/peptides were fHbp variant 2, NHBA peptides 24, 21, and 2, and PorA variable region 2 profiles 16-36 and 14. The nadA gene was present in 66 (23.2%) isolates. Estimated strain coverage by hSBA assay showed 78.4% of isolates were killed by pooled adolescent sera, and 51.4% and 64.9% (based on two different thresholds) were killed by pooled infant sera. Estimated coverage by gMATS (61.3%; prediction interval: 55.5%, 66.7%) was consistent with the infant hSBA assay results. Continued genomic surveillance is needed to evaluate the persistence of major MenB CCs in Argentina.
The most common clinical manifestations of invasive meningococcal disease include meningitis and septicemia, which can be deadly, and many survivors suffer long-term serious after-effects. Most cases of invasive meningococcal disease are caused by six meningococcal serogroups (types), including serogroup B. Although vaccines are available against meningococcal serogroup B infection, these vaccines target antigens that are highly diverse. Consequently, the effectiveness of vaccination may vary from country to country because the meningococcal serogroup B strains circulating in particular regions carry different forms of the target vaccine antigens. This means it is important to test serogroup B strains isolated from specific populations to estimate the percentage of strains that a vaccine is likely to be effective against (known as 'vaccine strain coverage'). The genetic Meningococcal Antigen Typing System (gMATS) was developed to predict strain coverage by the four-component meningococcal serogroup B vaccine, 4CMenB, against large numbers of serogroup B strains. In this study, we analyzed 284 invasive meningococcal serogroup B isolates collected between 2010 and 2014 in Argentina. Genetic analyses showed that the vaccine antigens of the isolates were diverse and some genetic characteristics had not been found in isolates from other countries. However, vaccine strain coverage estimated by gMATS was consistent with that reported in other parts of the world and with strain coverage results obtained for a subset via another method, the human serum bactericidal antibody (hSBA) assay. These results highlight the need for continued monitoring of circulating bacterial strains to assess the estimated strain coverage of meningococcal serogroup B vaccines.
Subject(s)
Antigens, Bacterial , Meningococcal Infections , Meningococcal Vaccines , Neisseria meningitidis, Serogroup B , Humans , Argentina/epidemiology , Meningococcal Vaccines/immunology , Meningococcal Vaccines/administration & dosage , Meningococcal Infections/microbiology , Meningococcal Infections/prevention & control , Meningococcal Infections/epidemiology , Infant , Adolescent , Child , Antigens, Bacterial/genetics , Antigens, Bacterial/immunology , Child, Preschool , Young Adult , Neisseria meningitidis, Serogroup B/genetics , Neisseria meningitidis, Serogroup B/isolation & purification , Neisseria meningitidis, Serogroup B/immunology , Adult , Female , Male , Whole Genome Sequencing , Bacterial Proteins/genetics , Bacterial Proteins/immunology , Genotype , Adhesins, Bacterial/genetics , Adhesins, Bacterial/immunology , Middle Aged , Porins/genetics , Porins/immunology , Serum Bactericidal Antibody Assay , Aged , Neisseria meningitidis/genetics , Neisseria meningitidis/immunology , Neisseria meningitidis/isolation & purification , Neisseria meningitidis/classificationABSTRACT
Secretin PilQ is an antigenically conserved outer membrane protein that is present in most meningococci and PorA is a major protein that elicits bactericidal immune response in humans following natural disease and immunization. In the present study, BALB/c mice were immunized subcutaneously with rPilQ406-770 or rPorA together with Freund's adjuvant (FA). Serum antibody responses to serogroup A and B Neisseria meningitides whole cells or purified proteins and functional activity of antibodies were determined by ELISA and serum bactericidal assay (SBA), respectively. Serum IgG responses were significantly increased in the immunized group with rPilQ406-770 or rPorA together with FA compared to control groups. IgG antibody response of mice immunized with rPilQ406-770 was significantly more than mice immunized with rPorA (OD at 450 nm was 1.6 versus 0.83). The booster injections were effective in increasing the responses of anti-rPilQ406-770 or anti-rPorA IgG significantly. Antisera produced against rPilQ406-770 or rPorA demonstrated strong surface reactivity to serogroup B N. meningitides in comparison with control groups. Antisera raised against rPorA or rPilQ406-770 and FA demonstrated SBA titers from 1/1024 to 1/2048 against serogroup B. The strongest bactericidal activity was detected in sera from mice immunized with rPilQ406-770 mixed with FA. These results suggest that rPilQ406-770 is a potential vaccine candidate for serogroup B N. meningitidis.
Subject(s)
Antibodies, Bacterial , Bacterial Outer Membrane Proteins , Immunoglobulin G , Meningococcal Vaccines , Mice, Inbred BALB C , Recombinant Proteins , Animals , Antibodies, Bacterial/blood , Antibodies, Bacterial/immunology , Bacterial Outer Membrane Proteins/immunology , Bacterial Outer Membrane Proteins/genetics , Immunoglobulin G/blood , Immunoglobulin G/immunology , Mice , Recombinant Proteins/immunology , Meningococcal Vaccines/immunology , Meningococcal Vaccines/administration & dosage , Neisseria meningitidis/immunology , Female , Freund's Adjuvant/administration & dosage , Freund's Adjuvant/immunology , Antibody Formation/immunology , Immunization , Enzyme-Linked Immunosorbent Assay , Serum Bactericidal Antibody Assay , Antigens, Bacterial/immunologyABSTRACT
Neisserial adhesin A (NadA) is a meningococcal surface protein included as recombinant antigen in 4CMenB, a protein-based vaccine able to induce protective immune responses against Neisseria meningitidis serogroup B (MenB). Although NadA is involved in the adhesion/invasion of epithelial cells and human myeloid cells, its function in meningococcal physiology is still poorly understood. To clarify the role played by NadA in the host-pathogen interaction, we sought to identify its cellular receptors. We screened a protein microarray encompassing 2,846 human and 297 mouse surface/secreted recombinant proteins using recombinant NadA as probe. Efficient NadA binding was revealed on the paired sialic acid-binding immunoglobulin-type lectins receptors 5 and 14 (Siglec-5 and Siglec-14), but not on Siglec-9 therein used as control. The interaction was confirmed by biochemical tools with the determination of the KD value in the order of nanomolar and the identification of the NadA binding site by hydrogen-deuterium exchange coupled to mass spectrometry. The N-terminal domain of the Siglec-5 that recognizes the sialic acid was identified as the NadA binding domain. Intriguingly, exogenously added recombinant soluble Siglecs, including Siglec-9, were found to decorate N. meningitidis surface in a NadA-dependent manner. However, Siglec-5 and Siglec-14 transiently expressed in CHO-K1 cells endorsed NadA binding and increased N. meningitidis adhesion/invasion while Siglec-9 did not. Taken together, Siglec-5 and Siglec-14 satisfy all features of NadA receptors suggesting a possible role of NadA in the acute meningococcal infection.IMPORTANCEBacteria have developed several strategies for cell colonization and immune evasion. Knowledge of the host and pathogen factors involved in these mechanisms is crucial to build efficacious countermoves. Neisserial adhesin A (NadA) is a meningococcal surface protein included in the anti-meningococcus B vaccine 4CMenB, which mediates adhesion to and invasion of epithelial cells. Although NadA has been shown to bind to other cell types, like myeloid and endothelial cells, it still remains orphan of a defined host receptor. We have identified two strong NadA interactors, Siglec-5 and Siglec-14, which are mainly expressed on myeloid cells. This showcases that NadA is an additional and key player among the Neisseria meningitidis factors targeting immune cells. We thus provide novel insights on the strategies exploited by N. meningitidis during the infection process, which can progress to a severe illness and death.
Subject(s)
Adhesins, Bacterial , Antigens, CD , Antigens, Differentiation, Myelomonocytic , Bacterial Adhesion , Host-Pathogen Interactions , Lectins , Humans , Adhesins, Bacterial/metabolism , Adhesins, Bacterial/genetics , Antigens, CD/metabolism , Antigens, CD/genetics , Lectins/metabolism , Lectins/genetics , Lectins/immunology , Animals , Antigens, Differentiation, Myelomonocytic/metabolism , Antigens, Differentiation, Myelomonocytic/genetics , Protein Binding , Mice , CHO Cells , Cricetulus , Neisseria meningitidis/genetics , Neisseria meningitidis/metabolism , Neisseria meningitidis/immunology , Recombinant Proteins/metabolism , Recombinant Proteins/genetics , Sialic Acid Binding Immunoglobulin-like Lectins/metabolism , Sialic Acid Binding Immunoglobulin-like Lectins/genetics , Epithelial Cells/microbiology , Epithelial Cells/metabolism , Epithelial Cells/immunology , Meningococcal Infections/microbiology , Meningococcal Infections/immunology , Receptors, Cell Surface/metabolism , Receptors, Cell Surface/genetics , Neisseria meningitidis, Serogroup B/genetics , Neisseria meningitidis, Serogroup B/immunology , Neisseria meningitidis, Serogroup B/metabolismABSTRACT
Meningococcal glycoconjugate vaccines sourced from capsular polysaccharides (CPSs) of pathogenic Neisseria meningitidis strains are well-established measures to prevent meningococcal disease. However, the exact structural factors responsible for antibody recognition are not known. CPSs of Neisseria meningitidis serogroups Y and W differ by a single stereochemical center, yet they evoke specific immune responses. Herein, we developed specific monoclonal antibodies (mAbs) targeting serogroups C, Y, and W and evaluated their ability to kill bacteria. We then used these mAbs to dissect structural elements responsible for carbohydrate-protein interactions. First, Men oligosaccharides were screened against the mAbs using ELISA to select putative lengths representing the minimal antigenic determinant. Next, molecular interaction features between the mAbs and serogroup-specific sugar fragments were elucidated using STD-NMR. Moreover, X-ray diffraction data with the anti-MenW CPS mAb enabled the elucidation of the sugar-antibody binding mode. Our findings revealed common traits in the epitopes of all three sialylated serogroups. The minimal binding epitopes typically comprise five to six repeating units. Moreover, the O-acetylation of the neuraminic acid moieties was fundamental for mAb binding. These insights hold promise for the rational design of optimized meningococcal oligosaccharides, opening new avenues for novel production methods, including chemical or enzymatic approaches.
Subject(s)
Antibodies, Monoclonal , Meningococcal Vaccines , Neisseria meningitidis , Polysaccharides, Bacterial , Serogroup , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/chemistry , Neisseria meningitidis/immunology , Neisseria meningitidis/chemistry , Meningococcal Vaccines/immunology , Meningococcal Vaccines/chemistry , Polysaccharides, Bacterial/immunology , Polysaccharides, Bacterial/chemistry , Antibodies, Bacterial/immunology , Epitopes/immunology , Epitopes/chemistry , Animals , Mice , Humans , Bacterial Capsules/immunology , Bacterial Capsules/chemistry , Antibody Formation/immunologyABSTRACT
Neisseria meningitidis, commonly known as the meningococcus, leads to substantial illness and death among children and young adults globally, revealing as either epidemic or sporadic meningitis and/or septicemia. In this study, we have designed a novel peptide-based chimeric vaccine candidate against the N. meningitidis strain 331,401 serogroup X. Through rigorous analysis of subtractive genomics, two essential cytoplasmic proteins, namely UPI000012E8E0(UDP-3-O-acyl-GlcNAc deacetylase) and UPI0000ECF4A9(UDP-N-acetylglucosamine acyltransferase) emerged as potential drug targets. Additionally, using reverse vaccinology, the outer membrane protein UPI0001F4D537 (Membrane fusion protein MtrC) identified by subcellular localization and recognized for its known indispensable role in bacterial survival was identified as a novel chimeric vaccine target. Following a careful comparison of MHC-I, MHC-II, T-cell, and B-cell epitopes, three epitopes derived from UPI0001F4D537 were linked with three types of linkers-GGGS, EAAAK, and the essential PADRE-for vaccine construction. This resulted in eight distinct vaccine models (V1-V8). Among them V1 model was selected as the final vaccine construct. It exhibits exceptional immunogenicity, safety, and enhanced antigenicity, with 97.7 % of its residues in the Ramachandran plot's most favored region. Subsequently, the vaccine structure was docked with the TLR4/MD2 complex and six different HLA allele receptors using the HADDOCK server. The docking resulted in the lowest HADDOCK score of 39.3 ± 9.0 for TLR/MD2. Immune stimulation showed a strong immune response, including antibodies creation and the activation of B-cells, T Cytotoxic cells, T Helper cells, Natural Killer cells, and interleukins. Furthermore, the vaccine construct was successfully expressed in the Escherichia coli system by reverse transcription, optimization, and ligation in the pET-28a (+) vector for the expression study. The current study proposes V1 construct has the potential to elicit both cellular and humoral responses, crucial for the developing an epitope-based vaccine against N. meningitidis strain 331,401 serogroup X.
Subject(s)
Meningococcal Vaccines , Neisseria meningitidis , Neisseria meningitidis/immunology , Neisseria meningitidis/genetics , Humans , Meningococcal Vaccines/immunology , Vaccinology/methods , Genomics , Computer Simulation , Epitopes, T-Lymphocyte/immunology , Epitopes, T-Lymphocyte/genetics , Epitopes, T-Lymphocyte/chemistry , Epitopes, B-Lymphocyte/immunology , Epitopes, B-Lymphocyte/chemistry , Epitopes, B-Lymphocyte/geneticsABSTRACT
OBJECTIVE: We evaluated the changes and molecular epidemiology of meningococcal carriage in military recruits after quadrivalent meningococcal conjugate vaccines (MenACWY) vaccination. METHODS: Oropharyngeal swabs were obtained at the beginning and end of the 5-week training. Carriage rates before and after vaccination were compared to estimate vaccine effectiveness (VE). Cultured isolates were characterized by multi-locus sequence typing (MLST). RESULTS: Of 866 vaccinated participants, the overall carriage rate was 10.6% prior to MenACWY vaccination and it tended to decrease to 9.5% after 5 weeks of vaccination (P = 0.424). Carriage rate of serogroup ACWY decreased significantly after vaccination (VEACWY = 72.6%, 95% CI: 36.3-88.2), and serogroup C was particularly reduced (VEC = 83.0%, 95% CI: 50.6-94.1), whereas non-groupable isolates increased significantly after vaccination (VENG = -76.1%, 95% CI: -176.2 to -13.1). Among 99 carriage isolates with complete MLST profiles, 45 different sequence types with nine clonal complexes (CCs) were identified, and 35.3% of the carriage isolates belonged to hypervirulent strains such as CC-32, CC-41/44, and CC-269. CONCLUSIONS: MenACWY vaccination in military recruits led to reduced carriage rates of serogroups C, W, and Y within a short 5-week period. However, serogroup B isolates belonging to the hypervirulent lineage remained after the implementation of MenACWY vaccination.
Subject(s)
Carrier State , Genotype , Meningococcal Infections , Meningococcal Vaccines , Military Personnel , Multilocus Sequence Typing , Neisseria meningitidis , Vaccines, Conjugate , Humans , Meningococcal Vaccines/administration & dosage , Meningococcal Vaccines/immunology , Neisseria meningitidis/genetics , Neisseria meningitidis/immunology , Neisseria meningitidis/classification , Meningococcal Infections/prevention & control , Meningococcal Infections/epidemiology , Meningococcal Infections/microbiology , Carrier State/microbiology , Carrier State/epidemiology , Prospective Studies , Male , Young Adult , Republic of Korea/epidemiology , Vaccines, Conjugate/administration & dosage , Vaccines, Conjugate/immunology , Female , Serogroup , Adult , VaccinationABSTRACT
The value of preventive medicine is superior to treatment with vaccinations occupying high priority. Nevertheless, heavy pressure has started to form in regard to strains not included in vaccines contributing to the changing epidemiology of pathogen subtypes leading to 'vaccine-induced strain replacement'. Among other mechanisms, increasing fitness of nonvaccine strains and metabolic shifts in the subtypes have been described. Classical examples include pneumococcal infections and viral diseases, such as the human papilloma virus. Recently, it has been described in SARS-CoV-2, leading to the emergence of new subtypes, such as Omicron and Delta variants. The phenomenon has also been reported in Mycobacterium tuberculosis, Neisseria meningitidis and rotavirus. This study addresses the concepts, examples and implications of this phenomenon.
[Box: see text].
Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/immunology , COVID-19/prevention & control , COVID-19/immunology , Vaccination , Mycobacterium tuberculosis/immunology , Vaccines/immunology , Vaccines/adverse effects , Neisseria meningitidis/immunologyABSTRACT
COVID-19, caused by SARS-CoV-2, and meningococcal disease, caused by Neisseria meningitidis, are relevant infectious diseases, preventable through vaccination. Outer membrane vesicles (OMVs), released from Gram-negative bacteria, such as N. meningitidis, present adjuvant characteristics and may confer protection against meningococcal disease. Here, we evaluated in mice the humoral and cellular immune response to different doses of receptor binding domain (RBD) of SARS-CoV-2 adjuvanted by N. meningitidis C:2a:P1.5 OMVs and aluminum hydroxide, as a combined preparation for these pathogens. The immunization induced IgG antibodies of high avidity for RBD and OMVs, besides IgG that recognized the Omicron BA.2 variant of SARS-CoV-2 with intermediary avidity. Cellular immunity showed IFN-γ and IL-4 secretion in response to RBD and OMV stimuli, demonstrating immunologic memory and a mixed Th1/Th2 response. Offspring presented transferred IgG of similar levels and avidity as their mothers. Humoral immunity did not point to the superiority of any RBD dose, but the group immunized with a lower antigenic dose (0.5 µg) had the better cellular response. Overall, OMVs enhanced RBD immunogenicity and conferred an immune response directed to N. meningitidis too.
Subject(s)
Antibodies, Viral , COVID-19 , Immunoglobulin G , Neisseria meningitidis , SARS-CoV-2 , Animals , Mice , Immunoglobulin G/blood , Neisseria meningitidis/immunology , Female , Antibodies, Viral/blood , Antibodies, Viral/immunology , COVID-19/prevention & control , COVID-19/immunology , SARS-CoV-2/immunology , Adjuvants, Immunologic/administration & dosage , COVID-19 Vaccines/immunology , COVID-19 Vaccines/administration & dosage , Immunity, Cellular , Immunity, Humoral , Mice, Inbred BALB C , Meningococcal Infections/prevention & control , Meningococcal Infections/immunology , Spike Glycoprotein, Coronavirus/immunology , Adjuvants, Vaccine/administration & dosage , Aluminum Hydroxide/administration & dosage , Aluminum Hydroxide/immunology , Immunization/methods , Antibody Affinity , Antibodies, Bacterial/blood , Antibodies, Bacterial/immunology , Meningococcal Vaccines/immunology , Meningococcal Vaccines/administration & dosage , Immunologic Memory , Th1 Cells/immunologyABSTRACT
The rates of nasopharyngeal meningococcal carriage in healthcare workers are unknown. Meningococcal vaccine is recommended for risk groups but healthcare workers are not included in risk groups for many countries. Herein, we aimed to investigate the nasopharyngeal meningococcal carriage rates, basal and after one dose of Men-ACWY-DT vaccine response on the 30th day by evaluating meningococcus IgG antibody levels and decolonization at month six after vaccination among the detected carriers. Nasopharyngeal swab samples were taken before vaccination to evaluate meningococcal carriage in healthcare workers. All participants received a single dose of Men-ACWY-DT vaccine. Serum samples were collected immediately before vaccination and again on day 30 post-vaccination. Antibodies in the stored sera were analyzed using the ELISA method. Participants who were determined to carry meningococci at the initial visit underwent another round of nasopharyngeal swab tests six months post-vaccination to check for decolonization. Between November 2020 and May 2021, we evaluated samples from 100 physicians [52 % females, 28.28 ± 4.45 (min: 24, max: 49)]. The majority of the physicians worked in the emergency department (45 %), followed by the infectious diseases clinic (14 %). Fifty-eight physicians had a history of at least one contact with a meningococcus-infected patient, and 53 (91.4 %) had used prophylactic antibiotics at least once due to this exposure. None of the study group nasopharyngeal swab cultures were positive for Neisseria meningitidis. Before the Men-ACWY-DT vaccine, anti-meningococcus IgG positivity was detected in the serum samples of only 3 (3 %) participants. By day 30 after vaccination, 48 % of participants showed positive for antibodies. As we didn't detect nasopharyngeal carriage in any participants, we didn't evaluate decolonization among carriers six months post-vaccination. Notably, detection of antibodies was evident in about half of the participants on day 30 after receiving a single dose of the Men-ACWY-DT vaccine.
Subject(s)
Antibodies, Bacterial , Carrier State , Health Personnel , Meningococcal Infections , Meningococcal Vaccines , Nasopharynx , Neisseria meningitidis , Humans , Male , Meningococcal Vaccines/immunology , Meningococcal Vaccines/administration & dosage , Female , Carrier State/immunology , Carrier State/microbiology , Adult , Antibodies, Bacterial/blood , Meningococcal Infections/prevention & control , Meningococcal Infections/immunology , Health Personnel/statistics & numerical data , Neisseria meningitidis/immunology , Nasopharynx/microbiology , Immunoglobulin G/blood , Vaccination/methods , Young Adult , Antibody Formation/immunology , Middle AgedABSTRACT
Epitope imprinting has shown better prospects to synthesize synthetic receptors for proteins. Here, dual epitope imprinted polymer electrode (DEIP) matrix was fabricated on gold surface of electrochemical quartz crystal microbalance (EQCM) for recognition of target epitope sequence in blood samples of patients suffering from brain fever. Epitope sequences from outer membrane protein Por B of Neisseria meningitidis (MC58) bacteria predicted through immunoinformatic tools were chosen for imprinting. Self-assembled monolayers (SAM) of cysteine appended epitope sequences on gold nanoparticles were subjected to polymerization prior to electrodeposition on gold coated EQCM electrode. The polymeric matrix was woven around the cysteine appended epitope SAMs through multiple monomers (3-sulfo propyl methacrylate potassium salt (3-SPMAP), benzyl methacrylate (BMA)) and crosslinker (N, N'-methylene-bis-acrylamide). On extraction of the peptide sequences, imprinted cavities were able to selectively and specifically bind targeted epitope sequences in laboratory samples as well as 'real' samples of patients. Selectivity of sensor was examined through mismatched peptide sequences and certain plasma proteins also. The sensor was able to show specific binding towards the blood samples of infected patients, even in the presence of 'matrix' and other plasma proteins such as albumin and globulin. Even other peptide sequences, similar to epitope sequences only with one or two amino acid mismatches were also unable to show any binding. The analytical performance of DEIP-EQCM sensor was tested through selectivity, specificity, matrix effect, detection limit (0.68-1.01 nM), quantification limit (2.05-3.05 nM) and reproducibility (RSD ~ 5%). Hence, a diagnostic tool for bacterium causing meningitis is successfully fabricated in a facile manner which will broaden the clinical access and make efficient population screening feasible.
Subject(s)
Electrodes , Epitopes , Gold , Molecular Imprinting , Neisseria meningitidis , Quartz Crystal Microbalance Techniques , Epitopes/immunology , Epitopes/chemistry , Humans , Neisseria meningitidis/immunology , Gold/chemistry , Biosensing Techniques/methods , Bacterial Proteins/chemistry , Bacterial Proteins/immunology , Metal Nanoparticles/chemistry , Porins/chemistry , Porins/immunologyABSTRACT
Invasive meningococcal disease (IMD) is a rare but serious illness, and adolescents and young adults in the United States are at increased risk. Here, we discuss US IMD history and how successful disease prevention through routine vaccination against the most common disease-causing serogroups (A, B, C, W, and Y) can inform future recommendations. Before the introduction of quadrivalent meningococcal conjugate (MenACWY) vaccines, most US cases of IMD were caused by serogroups B, C, and Y. After recommendation by the Advisory Committee on Immunization Practices for routine MenACWY vaccination of 11-12-year-olds in 2005, followed by a 2010 booster recommendation, MenCWY disease incidence declined dramatically, and vaccine coverage remains high. Two serogroup B (MenB) vaccines are licensed in the United States, but uptake is low compared with MenACWY vaccines, likely because Advisory Committee on Immunization Practices recommends MenB vaccination subject to shared clinical decision-making rather than routinely for all adolescents. The proportion of adolescent IMD caused by MenB has now increased. Pentavalent vaccines that protect against serogroups A, B, C, W, and Y may provide an optimal strategy for improving vaccination rates to ultimately reduce MenB incidence while maintaining the historically low rates of IMD caused by serogroups A, C, W, and Y.
Subject(s)
Meningococcal Infections , Meningococcal Vaccines , Humans , Meningococcal Vaccines/administration & dosage , United States , Adolescent , Meningococcal Infections/prevention & control , Vaccines, Conjugate/administration & dosage , Vaccination/statistics & numerical data , Neisseria meningitidis/immunology , ChildABSTRACT
Invasive meningococcal disease (IMD) is caused by Neisseria meningitidis, with the main serogroups responsible for the disease being A, B, C, W, X, and Y. To date, several vaccines targeting N. meningitidis have been developed albeit with a short-lived protection. Given that MenW and MenB are the most common causes of IMD in Europe, Turkey, and the Middle East, we aimed to develop an outer membrane vesicle (OMV) based bivalent vaccine as the heterologous antigen source. Herein, we compared the immunogenicity, and breadth of serum bactericidal activity (SBA) assay-based protective coverage of OMV vaccine to the X serotype with existing commercial meningococcal conjugate and polysaccharide (PS) vaccines in a murine model. BALB/c mice were immunized with preclinical batches of the Wâ +â B OMV vaccine, either adjuvanted with Alum, CpG ODN, or their combinations, and compared with a MenACYW conjugate vaccine (NimenrixTM, Pfizer), and a MenB OMV-based vaccine (Bexsero®, GSK), The immune responses were assessed through enzyme-linked immunosorbent assay (ELISA) and SBA assay. Antibody responses and SBA titers were significantly higher in the Wâ +â B OMV vaccine when adjuvanted with Alum or CpG ODN, as compared to the control groups. Moreover, the SBA titers were not only significantly higher than those achieved with available conjugated ACYW vaccines but also on par with the 4CMenB vaccines. In conclusion, the Wâ +â B OMV vaccine demonstrated the capacity to elicit robust antibody responses, surpassing or matching the levels induced by licensed meningococcal vaccines. Consequently, the Wâ +â B OMV vaccine could potentially serve as a viable alternative or supplement to existing meningococcal vaccines.
Subject(s)
Alum Compounds , Meningococcal Infections , Meningococcal Vaccines , Mice, Inbred BALB C , Neisseria meningitidis , Oligodeoxyribonucleotides , Animals , Meningococcal Vaccines/immunology , Meningococcal Vaccines/administration & dosage , Mice , Neisseria meningitidis/immunology , Alum Compounds/administration & dosage , Oligodeoxyribonucleotides/immunology , Oligodeoxyribonucleotides/administration & dosage , Female , Meningococcal Infections/prevention & control , Meningococcal Infections/immunology , Adjuvants, Immunologic/administration & dosage , Adjuvants, Immunologic/pharmacology , Antibodies, Bacterial/immunology , Antibodies, Bacterial/blood , Immunogenicity, Vaccine , Bacterial Outer Membrane/immunologyABSTRACT
The identification of an appropriate animal model for use in the development of meningococcal vaccines has been a challenge as humans are the only natural host for Neisseria meningitidis. Small animal models have been developed and are widely used to study the efficacy or immunogenicity of vaccine formulations generated against various diseases. Here, we describe the development and optimization of a mouse model for assessing the immunogenicity of candidate tetravalent meningococcal polysaccharide (MenACYW-TT) protein conjugate vaccines. Three inbred (BALB/c [H-2d], C3H/HeN [H-2k], or C57BL/6 [H-2b]) and one outbred (ICR [H-2g7]) mouse strains were assessed using serial two-fold dose dilutions (from 2 µg to 0.03125 µg per dose of polysaccharide for each serogroup) of candidate meningococcal conjugate vaccines. Groups of 10 mice received two doses of the candidate vaccine 14 days apart with serum samples obtained 14 days after the last dose for the evaluation of serogroup-specific anti-polysaccharide IgG by ELISA and bactericidal antibody by serum bactericidal assay (SBA). C3H/HeN and ICR mice had a more dose-dependent antibody response to all four serogroups than BALB/c and C57Bl/6 mice. In general, ICR mice had the greatest antibody dose-response range (both anti-polysaccharide IgG and bactericidal antibodies) to all four serogroups and were chosen as the model of choice. The 0.25 µg per serogroup dose was chosen as optimal since this was in the dynamic range of the serogroup-specific dose-response curves in most of the mouse strains evaluated. We demonstrate that the optimized mouse immunogenicity model is sufficiently sensitive to differentiate between conjugated polysaccharides, against unconjugated free polysaccharides and, to degradation of the vaccine formulations. Following optimization, this optimized mouse immunogenicity model has been used to assess the impact of different conjugation chemistries on immunogenicity, and to screen and stratify various candidate meningococcal conjugate vaccines to identify those with the most desirable profile to progress to clinical trials.
Subject(s)
Antibodies, Bacterial/blood , Meningococcal Infections/prevention & control , Meningococcal Vaccines/immunology , Neisseria meningitidis/immunology , Animals , Female , Immunogenicity, Vaccine , Meningococcal Infections/veterinary , Meningococcal Vaccines/administration & dosage , Mice , Mice, Inbred BALB C , Mice, Inbred C3H , Mice, Inbred C57BL , Mice, Inbred ICR , Models, Animal , Serogroup , Vaccines, Conjugate/administration & dosage , Vaccines, Conjugate/immunologyABSTRACT
BACKGROUND: In August, 2015, the UK implemented an emergency adolescent immunisation programme with the meningococcal ACWY conjugate vaccine to combat a national outbreak of meningococcal group W (MenW) disease due to a hypervirulent ST-11 complex strain, which is currently causing regional and national outbreaks worldwide. This immunisation programme specifically targeted adolescents aged 13-18 years, an age group with low disease incidence but high nasopharyngeal carriage, with the aim of interrupting transmission and providing indirect (herd) protection across the population. Here, we report the impact of the first 4 years of the programme in England. METHODS: Public Health England conducts meningococcal disease surveillance in England. Laboratory-confirmed cases of invasive meningococcal disease during the academic years 2010-11 to 2014-15 (Sept 1 to Aug 31) were used to predict post-vaccination trends, based on the assumption that cases would plateau 1 year after vaccine implementation (conservative scenario) or that cases would continue to rise for 4 years after vaccine implementation (extreme scenario). Vaccine uptake evaluated in August, 2019, was 37-41% in adolescents aged 18 years immunised in primary care and 71-86% in younger teenagers routinely vaccinated in school. Vaccine effectiveness was estimated with the indirect screening method. FINDINGS: MenW and MenY cases plateaued within 12 months and then declined, while MenC cases remained low throughout. Significant reductions were observed among adolescents aged 14-18 years for MenW (incidence rate ratio [IRR] 0·35 [95% CI 0·17-0·76]) and MenY (0·21 [0·07-0·59]) cases, with a non-significant reduction in MenC cases (0·11 [0·01-1·01]). Based on conservative and extreme scenarios, 205-1193 MenW cases were prevented through the indirect effects of the programme and 25 through direct protection. For MenY, an estimated 60-106 cases were prevented through the indirect effects of the programme and 19 through direct protection. Ignoring any residual effect from an earlier MenC-containing vaccine, the overall vaccine effectiveness against MenCWY disease combined was 94% (95% CI 80-99). INTERPRETATION: A meningococcal immunisation programme specifically targeting adolescent carriers succeeded in rapidly controlling a national MenW outbreak, even with moderate initial vaccine uptake. FUNDING: Public Health England.
Subject(s)
Disease Outbreaks/prevention & control , Immunization Programs , Meningococcal Infections/epidemiology , Meningococcal Infections/prevention & control , Meningococcal Vaccines/administration & dosage , Neisseria meningitidis, Serogroup W-135/immunology , Neisseria meningitidis/immunology , Adolescent , England/epidemiology , Humans , Serogroup , Vaccines, Conjugate/administration & dosageABSTRACT
Outer Membrane Vesicles (OMV) constitute a promising platform for the development of efficient vaccines. OMV can be decorated with heterologous antigens (proteins or polysaccharides), becoming attractive novel carriers for the development of multicomponent vaccines. Chemical conjugation represents a tool for linking antigens, also from phylogenetically distant pathogens, to OMV. Here we develop two simple and widely applicable conjugation chemistries targeting proteins or lipopolysaccharides on the surface of Generalized Modules for Membrane Antigens (GMMA), OMV spontaneously released from Gram-negative bacteria mutated to increase vesicle yield and reduce potential reactogenicity. A Design of Experiment approach was used to identify optimal conditions for GMMA activation before conjugation, resulting in consistent processes and ensuring conjugation efficiency. Conjugates produced by both chemistries induced strong humoral response against the heterologous antigen and GMMA. Additionally, the use of the two orthogonal chemistries allowed to control the linkage of two different antigens on the same GMMA particle. This work supports the further advancement of this novel platform with great potential for the design of effective vaccines.
Subject(s)
Bacterial Proteins/immunology , Bacterial Vaccines/immunology , Extracellular Vesicles/immunology , Protozoan Proteins/immunology , Protozoan Vaccines/immunology , Animals , Antibodies, Bacterial/immunology , Antigens, Bacterial/immunology , Bacterial Proteins/chemistry , Bacterial Vaccines/biosynthesis , Female , Lipopolysaccharides/immunology , Mice , Neisseria meningitidis/immunology , Plasmodium falciparum/immunology , Protozoan Proteins/chemistry , Protozoan Vaccines/biosynthesis , Salmonella typhimurium/immunology , Shigella sonnei/immunologyABSTRACT
Cluster randomized trials (cRCT) to assess vaccine effectiveness incorporate indirect effects of vaccination, helping to inform vaccination policy. To calculate the sample size for a cRCT, an estimate of the intracluster correlation coefficient (ICC) is required. For infectious diseases, shared characteristics and social mixing behaviours may increase susceptibility and exposure, promote transmission and be a source of clustering. We present ICCs from a school-based cRCT assessing the effectiveness of a meningococcal B vaccine (Bexsero, GlaxoSmithKline) on reducing oropharyngeal carriage of Neisseria meningitidis (Nm) in 34,489 adolescents from 237 schools in South Australia in 2017/2018. We also explore the contribution of shared behaviours and characteristics to these ICCs. The ICC for carriage of disease-causing Nm genogroups (primary outcome) pre-vaccination was 0.004 (95% CI: 0.002, 0.007) and for all Nm was 0.007 (95%CI: 0.004, 0.011). Adjustment for social behaviours and personal characteristics reduced the ICC for carriage of disease-causing and all Nm genogroups by 25% (to 0.003) and 43% (to 0.004), respectively. ICCs are also reported for risk factors here, which may be outcomes in future research. Higher ICCs were observed for susceptibility and/or exposure variables related to Nm carriage (having a cold, spending ≥1 night out socializing or kissing ≥1 person in the previous week). In metropolitan areas, nights out socializing was a highly correlated behaviour. By contrast, smoking was a highly correlated behaviour in rural areas. A practical example to inform future cRCT sample size estimates is provided.
Subject(s)
Meningococcal Infections/immunology , Meningococcal Vaccines/immunology , Neisseria meningitidis/immunology , Adolescent , Cluster Analysis , Female , Humans , Male , Risk Factors , Schools , South Australia , VaccinationABSTRACT
A peptide from the P0 acidic ribosomal protein (pP0) of ticks conjugated to keyhole limpet hemocyanin from Megathura crenulata has shown to be effective against different tick species when used in host vaccination. Turning this peptide into a commercial anti-tick vaccine will depend on finding the appropriate, technically and economically feasible way to present it to the host immune system. Two conjugates (p64K-Cys1pP0 and p64K-ßAla1pP0) were synthesized using the p64K carrier protein from Neisseria meningitidis produced in Escherichia coli, the same cross-linking reagent, and two analogues of pP0. The SDS-PAGE analysis of p64K-Cys1pP0 showed a heterogeneous conjugate compared to p64K-ßAla1pP0 that was detected as a protein band at 91kDa. The pP0/p64K ratio determined by MALDI-MS for p64K-Cys1pP0 ranged from 1 to 8, being 3-5 the predominant ratio, while in the case of p64K-ßAla1pP0 this ratio was 5-7. Cys1pP0 was partially linked to 35 out of 39 Lys residues and the N-terminal end, while ßAla1pP0 was mostly linked to the six free cysteine residues, to the N-terminal end, and, in a lesser extent, to Lys residues. The assignment of the conjugation sites and side reactions were based on the identification of type 2 peptides. Rabbit immunizations showed the best anti-pP0 titers and the highest efficacy against Rhipicephalus sanguineus ticks when the p64K-Cys1pP0 was used as vaccine antigen. The presence of high molecular mass aggregates observed in the SDS-PAGE analysis of p64K-Cys1pP0 could be responsible for a better immune response against pP0 and consequently for its better efficacy as an anti-tick vaccine. Graphical abstract.
Subject(s)
Bacterial Outer Membrane Proteins/immunology , Chromatography, Liquid/methods , Neisseria meningitidis/immunology , Tandem Mass Spectrometry/methods , Ticks/immunology , Vaccines/immunology , Animals , Electrophoresis, Polyacrylamide Gel , Hemocyanins/immunology , Rabbits , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methodsABSTRACT
Complement deficient patients are susceptible to rare meningococcal serogroups. A 6-year-old girl presented with serogroup Z meningitis. This led to identification of a C8 deficiency. The MenB-4C vaccine induced cross-reactive antibodies to serogroup Z and increased in vitro opsonophagocytic killing and may thus protect complement deficient patients.
Subject(s)
Complement C8/deficiency , Cross Protection/immunology , Meningitis/microbiology , Meningococcal Vaccines/immunology , Neisseria meningitidis/immunology , Serogroup , Antibodies, Bacterial/immunology , Child , Cross Reactions/immunology , Female , Hereditary Complement Deficiency Diseases , Humans , Meningitis/diagnosis , Meningitis/immunology , Meningococcal Infections/prevention & control , Meningococcal Vaccines/administration & dosage , Neisseria meningitidis/classification , OpsonizationABSTRACT
Carbohydrate-binding antibodies play diverse and critical roles in human health. Endogenous carbohydrate-binding antibodies that recognize bacterial, fungal, and other microbial carbohydrates prevent systemic infections and help maintain microbiome homeostasis. Anti-glycan antibodies can have both beneficial and detrimental effects. For example, alloantibodies to ABO blood group carbohydrates can help reduce the spread of some infectious diseases, but they also impose limitations for blood transfusions. Antibodies that recognize self-glycans can contribute to autoimmune diseases, such as Guillain-Barre syndrome. In addition to endogenous antibodies that arise through natural processes, a variety of vaccines induce anti-glycan antibodies as a primary mechanism of protection. Some examples of approved carbohydrate-based vaccines that have had a major impact on human health are against pneumococcus, Haemophilus influeanza type b, and Neisseria meningitidis. Monoclonal antibodies specifically targeting pathogen associated or tumor associated carbohydrate antigens (TACAs) are used clinically for both diagnostic and therapeutic purposes. This review aims to highlight some of the well-studied and critically important applications of anti-carbohydrate antibodies.