Virulence Antigens Research Articles

A Novel Multi-epitope Vaccine Based on Virulence Stimulating Two-component Protein EsrA Against Fish Pathogenic Edwardsiella tarda – An Immunoinformatic Approach

Edwardsiellosis, caused by the gram-negative pathogen Edwardsiella tarda, is a major global aquaculture threat. Despite vaccination being a potential strategy, development of effective vaccines remains a challenge. The study aimed to develop a multi-epitope vaccine (EsrAmev) against virulent EsrA antigen in fish pathogenic E. tarda using an immunoinformatic approach. The study identified antigenic, non-allergenic, and nontoxic epitopes for cytotoxic T lymphocytes, helper T-lymphocytes, and linear Blymphocytes. They were combined to create the EsrAmev construct, with TLR4 agonist added for the immunogenicity. The physiochemical analysis of EsrAmev by ProtParam server showed a molecular weight of 29 kDa, an antigenicity score of 0.5966, and a solubility of 0.823563 with immunogenic, non-allergenic and non-toxic properties. Robetta, Mod, and Galaxy refiner servers refined the EsrAmev 3D structure, achieving 97.4% RAMA-favoured region, stable interactions, binding stability, and structural stiffness with TLR4 receptor. The EsrAmev construct, optimized for high immune responses in Escherichia coli K12 model, was successfully cloned into the pET28a (+) vector in silico for future wet lab applications. These findings suggests that the EsrAmev multi-epitope vaccine might have potential for the prophylaxis of E.tardacausing Fish Edwardsiellosis.

Role of H.pylori in Chronic Sore Throat by Using H.pylori Line.

Pharyngitis is an inflammation of the mucous membranes of the oropharynx. Pharyngitis may be caused by an infectious or noninfectious disease. Noninfectious diseases of pharynx include allergies, trauma, cancer, reflux and certain toxins. Infection with H. Pylori is associated with developing chronic sore throat, gastritis, gastric or duodenal ulcer, gastric cancer and MALT lymphoma. There are many different investigations to diagnose H pylori as H pylori antigen in blood and stool, urea breath test but, H. Pylori line is a new test for detection of the virulent strains. There are many lines of H pylori therapy in the form of PPIs and antibiotics for about two weeks. This study aimed to detect role of H pylori in chronic pharyngitis. 85 patients who had chronic pharyngitis with normal CBC, WBCS, lymphocyte, monocyte and eosinophils with negative ASO titer and throat swab. These patients did H pylori line to detect H pylori virulent antigen. 77 patients with chronic pharyngitis are positive H pylori and after medical treatment 68 patients became negative. H. Pylori line is a new test for detection of the virulent strains and screening H pylori carrier at risk of developing gastric and duodenal ulcers as well as cancer.

The cloning of ESAT-6, EspC and Rv2029c genes obtained from an Indonesian tuberculosis-infected patient

Early secreted antigenic target of 6-kDa protein (ESAT-6), a protein related to tuberculosis virulence (EspC) and latent antigen Rv2029c are important biomarkers for Mycobacterium tuberculosis prevention. Recent advances in subunit protein vaccines offer promising solutions to the inadequacies of existing BCG vaccines. In this study, these antigens were cloned into pET plasmid series to express the genes using the Escherichia coli expression system. Polymerase Chain Reaction was used to amplify the target genes from genome DNA isolated from Indonesia tuberculosis-infected patient’s sputum. A 309 bp of ESAT-6 fragment and a 337 bp of EspC fragment were inserted into pET-21b. Meanwhile, the 1038 bp of Rv2029c fragment was inserted into pET-32b. All constructs were transformed into Escherichia coli TOP10 and screened on Luria Bertani agar media containing ampicillin. The transformants were subjected to colony PCR using T7 universal primers followed by plasmid isolation to confirm the recombination. All genes were successfully cloned into the pET plasmid series. These results serve as a basis for further studies to express the recombinant protein as a booster vaccine.

Advances in Helicobacter pylori vaccine research: From candidate antigens to adjuvants-A review.

Helicobacter pylori is a Gram-negative, spiral-shaped bacterium that infects approximately 50% of the world's population and has been strongly associated with chronic gastritis, peptic ulcers, gastric mucosa-associated lymphoma, and gastric cancer. The elimination of H. pylori is currently considered one of the most effective strategies for the treatment of gastric-related diseases, so antibiotic therapy is the most commonly used regimen for the treatment of H. pylori infection. Although this therapy has some positive effects, antibiotic resistance has become another clinically prominent problem. Therefore, the development of a safe and efficient vaccine has become an important measure to prevent H. pylori infection. PubMed and ClinicalTrials.gov were systematically searched from January 1980 to March 2023 with search terms-H. pylori vaccine, adjuvants, immunization, pathogenesis, and H. pylori eradication in the title and/or abstract of literature. A total of 5182 documents were obtained. Based on the principles of academic reliability, authority, nearly publicated, and excluded the similar documents, finally, 75 documents were selected, organized, and analyzed. Most of the candidate antigens used as H. pylori vaccines in these literatures are whole-cell antigens and virulence antigens such as UreB, VacA, CagA, and HspA, and the main types of vaccines for H. pylori are whole bacteria vaccines, vector vaccines, subunit vaccines, nucleic acid vaccines, epitope vaccines, etc. Some vaccines have shown good immune protection in animal trials; however, few vaccines show good in clinical trials. The only H. pylori vaccine passed phase 3 clinical trial is a recombinant subunit vaccine using Urease subunit B (UreB) as the vaccine antigen, and it shows good prophylactic effects. Meanwhile, the adjuvant system for vaccines against this bacterium has been developed considerably. In addition to the traditional mucosal adjuvants such as cholera toxin (CT) and E. coli heat labile enterotoxin (LT), there are also promising safer and more effective mucosal adjuvants. All these advances made safe and effective H. pylori vaccines come into service as early as possible. This review briefly summarized the advances of H. pylori vaccines from two aspects, candidates of antigens and adjuvants, to provide references for the development of vaccine against this bacterium. We also present our prospects of exosomal vaccines in H. pylori vaccine research, in the hope of inspiring future researchers.

A self-amplifying RNA vaccine provides protection in a murine model of bubonic plague.

Mice were immunized with a combination of self-amplifying (sa) RNA constructs for the F1 and V antigens of Yersinia pestis at a dose level of 1 μg or 5 μg or with the respective protein sub-units as a reference vaccine. The immunization of outbred OF1 mice on day 0 and day 28 with the lowest dose used (1 μg) of each of the saRNA constructs in lipid nanoparticles protected 5/7 mice against subsequent sub-cutaneous challenge on day 56 with 180 cfu (2.8 MLD) of a 2021 clinical isolate of Y. pestis termed 10-21/S whilst 5/7 mice were protected against 1800cfu (28MLD) of the same bacteria on day 56. By comparison, only 1/8 or 1/7 negative control mice immunized with 10 μg of irrelevant haemagglutin RNA in lipid nanoparticles (LNP) survived the challenge with 2.8 MLD or 28 MLD Y. pestis 10-21/S, respectively. BALB/c mice were also immunized with the same saRNA constructs and responded with the secretion of specific IgG to F1 and V, neutralizing antibodies for the V antigen and developed a recall response to both F1 and V. These data represent the first report of an RNA vaccine approach using self-amplifying technology and encoding both of the essential virulence antigens, providing efficacy against Y. pestis. This saRNA vaccine for plague has the potential for further development, particularly since its amplifying nature can induce immunity with less boosting. It is also amenable to rapid manufacture with simpler downstream processing than protein sub-units, enabling rapid deployment and surge manufacture during disease outbreaks.

A novel vaccine candidate against A. baumannii based on a new OmpW family protein (OmpW2); structural characterization, antigenicity and epitope investigation, and in-vivo analysis

A. baumannii is an MDR pathogen whose SARS-CoV-2 has recently increased its mortality rate in hospitalized patients. So, the virulence factors investigation and design of a vaccine against this bacterium seem to be critical. In this regard, the OmpW2 protein was structurally characterized by this study, and its B-T cell epitopes were mapped by bioinformatic tools. In-vivo analyses were employed to verify the immunogenicity of this protein and its selected epitopes. The results indicated that OmpW2 is a conserved virulent antigen, not toxic for the host, and not similar to the human or mouse proteome. A putative interaction between OmpW2 and a Fe–S-cluster redox enzyme was detected. Based on the results, OmpW2 belongs to the OmpW superfamily and eight beta sheets have been predicted in its tight beta-barrel structure. Several exposed epitopes were detected in the OmpW2 sequence and structure, and a sub-unit potential vaccine was generated based on the epitopes. The ELISA results indicated that after the second booster vaccination of BALB/c mice with the whole OmpW2 protein or its sub-unit fragment, the IgG titer significantly raised (p < 0.05). The mortality rate and the bacterial burden in the lung, liver, kidney, and spleen in both passive and active immunized mice were significantly decreased (p ≤ 0.001). In-vivo experiments confirmed that the OmpW2 whole protein and its sub-unit fragment induce the host immune system and can be applied to design a commercial vaccine or diagnostic kit.

Protective Effect of the T1212C Macrophage Mannose Receptor Gene Polymorphism on Pulmonary Tuberculosis

The interaction between the mannose receptor, which is encoded by the macrophage mannose receptor (MMR) gene, and the most virulent antigen (the mannose-capped lipoarabinomannan) cell wall of virulent strains of Mycobacterium tuberculosis trigger an innate and adaptive immune response. It also produces pro and anti-inflammatory cytokines, which play a role in the pathogenesis of tuberculosis (TB) infection. Therefore, MMR gene polymorphism is a risk factor and is associated with the prognosis for active pulmonary TB. This study aimed to determine the correlation between MMR gene polymorphism and active or latent pulmonary tuberculosis. In this phase, MMR gene polymorphism was analyzed using a case-control design consisting of 74 control group subjects (patients with latent TB) and 74 case groups (patients with active pulmonary TB). The subject’s MMR gene DNA sequencing examination. The study was conducted at the Teaching Hospital, Faculty of Medicine, Universitas Padjadjaran Bandung, from February 2014 to January 2015. The statistical analysis used chi-square and odds ratio. The study’s result has shown the MMR gene polymorphism factor that correlated to the incidence of active pulmonary TB was T1212C (OR=0.253; 95% CI=0.111−0.575; p=0.001). There was an MMR gene in one SNP in the control group (C1323T) only and five single nucleotide polymorphisms (SNPs) in both groups (C1303T, C1221, T1212C, G1186A, and G1195A). Therefore, it can be concluded that MMR gene polymorphism on the T1212C site correlated with the incidence of active pulmonary tuberculosis and was protective.

Procedure for preparation, certification, and storage of a seed lot of the &lt;i&gt;Mycobacterium bovis&lt;/i&gt; BCG-I (Russia) vaccine strain

To date, the Bacillus Calmette–Guérin (BCG) vaccine has been the only medicinal product for active mass childhood immunisation against tuberculosis in the Russian Federation. Industrial-scale batches of the BCG vaccine are manufactured using a seed-lot system, which provides for producing the vaccine for civil circulation from a single batch of seed material, a lyophilisate of Mycobacterium bovis BCG. National and international documents touch upon the evaluation of BCG vaccine seed material in terms of its quality attributes in small separate sections containing brief descriptions and/or lists of attributes and control methods. It is relevant to bring together the information on receipt, certification, and storage of the inoculum (the seed lot) for production of the Russian BCG vaccine. The aim of the study was a comparative assessment of the main characteristics of and control methods for the inoculum of the Russian vaccine strain, M. bovis BCG-I, set out in the national and international requirements for BCG vaccines. The article summarises literature data on the history of BCG substrains and the variability of their characteristics and presents a brief account of the origin of the Russian BCG-I substrain. It considers the control methods specified in the national and international requirements for the inoculum for the BCG vaccine. The study demonstrated the practical possibility of identifying BCG down to the substrain level with subsequent determination of genetic properties that characterise genomic stability of the substrain. The article presents the results of the comparative analysis of data on stability of lyophilisates of M. bovis BCG-I seed lots (Russia). Particular attention is paid to biological methods for controlling the seed lot (determination of residual virulence, including BCG survival) and the immunobiological method for controlling BCG for the absence of the genes responsible for virulence antigen expression (animal skin tests with Diaskintest®). The authors concluded that the control of stability of genetic and biological properties throughout the entire period of seed lot production and storage makes it possible to obtain BCG vaccines that meet all the regulatory requirements.

Spray-dried pneumococcal membrane vesicles are promising candidates for pulmonary immunization

Pneumococcal infections represent a global health threat, which requires novel vaccine developments. Extracellular vesicles are secreted from most cells, including prokaryotes, and harbor virulence factors and antigens. Hence, bacterial membrane vesicles (MVs) may induce a protective immune response. For the first time, we formulate spray-dried gram-positive pneumococcal MVs-loaded vaccine microparticles using lactose/leucine as inert carriers to enhance their stability and delivery for pulmonary immunization. The optimized vaccine microparticles showed a mean particle size of 1–2 µm, corrugated surface, and nanocrystalline nature. Their aerodynamic diameter of 2.34 µm, average percentage emitted dose of 88.8%, and fine powder fraction 79.7%, demonstrated optimal flow properties for deep alveolar delivery using a next-generation impactor. Furthermore, confocal microscopy confirmed the successful encapsulation of pneumococcal MVs within the prepared microparticles. Human macrophage-like THP-1 cells displayed excellent viability, negligible cytotoxicity, and a rapid uptake around 60% of fluorescently labeled MVs after incubation with vaccine microparticles. Moreover, vaccine microparticles increased the release of pro-inflammatory cytokines tumor necrosis factor and interleukin-6 from primary human peripheral blood mononuclear cells. Vaccine microparticles exhibited excellent properties as promising vaccine candidates for pulmonary immunization and are optimal for further animal testing, scale-up and clinical translation.

Prevalence of Virulence Genes and Antigen Pattern in Helicobacter pylori-Infected Patients and the Level of Some Inflammatory Cytokines Compared with Non-infected Individuals

Background: The worldwide prevalence of Helicobacter pylori is about 50%. This bacterium needs a number of virulence factors for pathogenesis. Objectives: This study aimed to determine the prevalence of virulence genes (ureB, cytotoxin-associated gene A [cagA], and vacuolating cytotoxin [vacA]), as well as the antigenic profile in H. pylori strains. Methods: Eighty-five patients with abdominal pain, including 46 H. pylori-positive and 39 H. pylori-negative cases, were enrolled in this study. The serum levels of interleukin (IL)-17F, tumor necrosis factor α (TNF-α), and interferon γ (IFN-γ) cytokines were measured by multiplex kits and flow cytometry. After molecular identification by the ureC gene, vacA, cagA, and ureB genes were detected by polymerase chain reaction (PCR). Finally, after antigenic extraction, the whole-cell protein was exhibited by sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS-PAGE). Results: The prevalence of vacA, ureB, and cagA genes were 91.3%, 67.39%, and 50%, respectively. The frequency of genes and cell surface antigens were not significantly different based on the gastritis severity (P &gt; 0.05). IL-17F significantly (P = 0.046) increased in the presence of 19.5 kDa (outer membrane protein [OMP]). Moreover, the OMP antigen significantly enhanced immunoglobulin A (IgA; P = 0.013). In the presence of the 66-kDa (ureB) antigen, the serum level of IFN-γ increased (p = 0.041). Finally, the CagA protein led to increased IgG antibody levels (p = 0.027). Conclusions: Early detection of H. pylori infection can play a crucial role in managing it. Our results suggest that IL-17F, TNF-α, and IFN-γ cytokines could be diagnostic markers. However, further studies are required to fully investigate this suggestion.

The role of Akkermansia muciniphila in obesity, diabetes and atherosclerosis.

Alteration in the composition of the gut microbiota can lead to a number of chronic clinical diseases. Akkermansia muciniphila is an anaerobic bacteria constituting 3-5% of the gut microbial community in healthy adults. This bacterium is responsible for degenerating mucin in the gut; its scarcity leads to diverse clinical disorders. In this review, we focus on the role of A. muciniphila in diabetes, obesity and atherosclerosis, as well as the use of this bacterium as a next-generation probiotic. In regard to obesity and diabetes, human and animal trials have shown that A. muciniphila controls the essential regulatory system of glucose and energy metabolism. However, the underlying mechanisms by which A. muciniphila alleviates the complications of obesity, diabetes and atherosclerosis are unclear. At the same time, its abundance suggests improved metabolic disorders, such as metabolic endotoxemia, adiposity insulin resistance and glucose tolerance. The role of A. muciniphila is implicated in declining aortic lesions and atherosclerosis. Well-characterized virulence factors, antigens and cell wall extracts of A. muciniphila may act as effector molecules in these diseases. These molecules may provide novel mechanisms and strategies by which this bacterium could be used as a probiotic for the treatment of obesity, diabetes and atherosclerosis.

Transcutaneous Vaccination with Conjugate Typhoid Vaccine Vi-DT Induces Systemic, Mucosal, and Memory Anti-Polysaccharide Responses.

.Transcutaneous vaccination can induce both mucosal and systemic immune responses. However, there are few data on anti-polysaccharide responses following transcutaneous vaccination of polysaccharides, despite the role that anti-polysaccharide responses play in protecting against intestinal mucosal and respiratory pathogens. Whether transcutaneous vaccination with a conjugate polysaccharide vaccine would be able to induce memory responses is also unknown. To address this, we transcutaneously vaccinated mice with virulence antigen (Vi) polysaccharide of Salmonella enterica serovar Typhi (the cause of typhoid fever), either in unconjugated or conjugated form (the latter as a Vi-DT conjugate). We also assessed the ability of the immunoadjuvant cholera toxin to impact responses following vaccination. We found that presenting Vi in a conjugate versus nonconjugate form transcutaneously resulted in comparable serum IgG responses but higher serum and lamina propria lymphocyte IgA anti-Vi responses, as well as increased IgG memory responses. The addition of immunoadjuvant did not further increase these responses; however, it boosted fecal IgA and serum IgG anti-Vi responses. Our results suggest that transcutaneous vaccination of a conjugate vaccine can induce systemic as well as enhanced mucosal and memory B-cell anti-polysaccharide responses.

Bordetella pertussis Induces Interferon Gamma Production by Natural Killer Cells, Resulting in Chemoattraction by Respiratory Epithelial Cells.

BackgroundWhooping cough is caused by infection of the airways with Bordetella pertussis (Bp). As interferon gamma (IFN-γ) is essential for protective immunity against Bp, we investigated how IFN-γ is induced by Bp or the virulence antigens filamentous hemagglutinin adhesin, pertactin, or pertussis toxin, and how IFN-γ contributes to local immune responses in humans.MethodsPeripheral blood mononuclear cells (PBMCs) from healthy donors and/or respiratory epithelial cells were stimulated with soluble antigens or inactivated intact Bp and the presence or absence of blocking antibodies or chemokines. Supernatants and cells were analyzed for IFN-γ and chemokine production, and lymphocyte migration was tested using epithelial supernatants.ResultsThe soluble antigens failed to induce IFN-γ production, whereas inactivated Bp induced IFN-γ production. Natural killer (NK) cells were the main source of IFN-γ production, which was enhanced by interleukin 15. Epithelial–PBMC co-cultures showed robust IFN-γ–dependent CXCL9 and CXCL10 production by the epithelial cells following stimulation with IFN-γ and Bp. The epithelial-derived chemokines resulted in CXCR3-dependent recruitment of NK and T cells.ConclusionsInactivated Bp, but not antigens, induced potent IFN-γ production by NK cells, resulting in chemoattraction of lymphocytes toward the respiratory epithelium. These data provide insight into the requirements for IFN-γ production and how IFN-γ enhances local immune responses to prevent Bp-mediated disease.

Extracellular Vesicles as Vehicles for the Delivery of Biologically Active Fungal Molecules.

Extracellular vesicles (EVs) are membranous structures surrounded by a lipid bilayer required for the export of fungal proteins, lipids, toxins, nucleic acids, pigments, and polysaccharides. Proteomic studies of the content of fungal EVs revealed the presence of molecules involved in cell metabolism, signal transduction, and virulence, among others. EVs are evolutionarily conserved in all three domains of life and play important roles in cell-cell communication. Recently, the bidirectional transport of EVs was characterized through the demonstration that EVs can be released and captured by fungal cells. In fungi, EVs participate in immunomodulation through the delivery of virulence factors, antigens and allergens, but further studies are necessary to investigate their potential roles as carriers of diagnostic biomarkers and in drug delivery or antifungal resistance transmission. In this review, we discuss the roles of fungal EVs and their cargo in cell-cell communication, host-pathogen interactions, and environmental perception. The functions of EVs as vehicles for transporting fungal proteins and virulence factors are also addressed, as well as their use as biomarkers for the diagnosis of diseases and possible participation in antifungal responses.

A High-Resolution Map of SBP1 Interactomes in Plasmodium falciparum-infected Erythrocytes.

SummaryThe pathogenesis of malaria parasites depends on host erythrocyte modifications that are facilitated by parasite proteins exported to the host cytoplasm. These exported proteins form a trafficking complex in the host cytoplasm that transports virulence determinants to the erythrocyte surface; this complex is thus essential for malaria virulence. Here, we report a comprehensive interaction network map of this complex. We developed authentic, unbiased, highly sensitive proteomic approaches to determine the proteins that interact with a core component of the complex, SBP1 (skeleton-binding protein 1). SBP1 interactomes revealed numerous exported proteins and potential interactors associated with SBP1 intracellular trafficking. We identified several host-parasite protein interactions and linked the exported protein MAL8P1.4 to Plasmodium falciparum virulence in infected erythrocytes. Our study highlights the complicated interplay between parasite and host proteins in the host cytoplasm and provides an interaction dataset connecting dozens of exported proteins required for P. falciparum virulence.

The evolving nature of Bordetella pertussis in Ontario, Canada, 2009-2017: strains with shifting genotypes and pertactin deficiency.

This study examined the evolving nature of Bordetella pertussis in Ontario, Canada, by characterizing isolates for their genotypes and expression of pertactin (PRN). From 2009 to 2017, 413 B. pertussis were cultured from pertussis cases at the Public Health Ontario Laboratory. Their genotypes were determined by partial gene sequence analysis of their virulence and (or) vaccine antigens: filamentous haemagglutinin, PRN, fimbriae 3, and pertussis toxin, including the promoter region. Expression of PRN was measured by Western immunoblot. Two predominant genotypes, ST-1 and ST-2, were found throughout the study and were responsible for 47.5% and 46.3% of all case isolates, respectively. The prevalence of ST-1 appeared to fluctuate from 80.3% in 2009 to 20.0% in 2014 and 58.5% in 2017, while the prevalence of ST-2 changed from 18.4% in 2009 to 80.0% in 2014 and 26.2% in 2017. A PRN-deficient strain was first noted in 2011 (16.7%), and its prevalence increased to 70.8% in 2016 but decreased to 46.2% in 2017. More ST-2 (46.6%) than ST-1 (16.8%) strains were associated with PRN deficiency. Newer ST-21 and ST-22 found in 2015-2017 were uniformly PRN deficient. The impact of the evolving nature of B. pertussis on disease epidemiology requires further longitudinal studies.

The knob protein KAHRP assembles into a ring-shaped structure that underpins virulence complex assembly.

Plasmodium falciparum mediates adhesion of infected red blood cells (RBCs) to blood vessel walls by assembling a multi-protein complex at the RBC surface. This virulence-mediating structure, called the knob, acts as a scaffold for the presentation of the major virulence antigen, P. falciparum Erythrocyte Membrane Protein-1 (PfEMP1). In this work we developed correlative STochastic Optical Reconstruction Microscopy–Scanning Electron Microscopy (STORM-SEM) to spatially and temporally map the delivery of the knob-associated histidine-rich protein (KAHRP) and PfEMP1 to the RBC membrane skeleton. We show that KAHRP is delivered as individual modules that assemble in situ, giving a ring-shaped fluorescence profile around a dimpled disk that can be visualized by SEM. Electron tomography of negatively-stained membranes reveals a previously observed spiral scaffold underpinning the assembled knobs. Truncation of the C-terminal region of KAHRP leads to loss of the ring structures, disruption of the raised disks and aberrant formation of the spiral scaffold, pointing to a critical role for KAHRP in assembling the physical knob structure. We show that host cell actin remodeling plays an important role in assembly of the virulence complex, with cytochalasin D blocking knob assembly. Additionally, PfEMP1 appears to be delivered to the RBC membrane, then inserted laterally into knob structures.

Correlates of infection with Helicobacter pylori positive and negative cytotoxin-associated gene A phenotypes among Arab and Jewish residents of Jerusalem.

We examined the prevalence and correlates of Helicobacter pylori (H. pylori) infection according to cytotoxin-associated gene A (CagA) phenotype, a main virulence antigen, among the ethnically diverse population groups of Jerusalem. A cross-sectional study was undertaken in Arab (N = 959) and Jewish (N = 692) adults, randomly selected from Israel's national population registry in age-sex and population strata. Sera were tested for H. pylori immunoglobulin G (IgG) antibodies. Positive samples were tested for virulence IgG antibodies to recombinant CagA protein, by enzyme-linked immunosorbent assay. Multinomial regression models were fitted to examine associations of sociodemographic factors with H. pylori phenotypes. H. pylori IgG antibody sero-prevalence was 83.3% (95% confidence interval (CI) 80.0%-85.5%) and 61.4% (95% CI 57.7%-65.0%) among Arabs and Jews, respectively. Among H. pylori positives, the respective CagA IgG antibody sero-positivity was 42.3% (95% CI 38.9%-45.8%) and 32.5% (95% CI 28.2%-37.1%). Among Jews, being born in the Former Soviet Union, the Middle East and North Africa, vs. Israel and the Americas, was positively associated with CagA sero-positivity. In both populations, sibship size was positively associated with both CagA positive and negative phenotypes; and education was inversely associated. In conclusion, CagA positive and negative infection had similar correlates, suggesting shared sources of these two H. pylori phenotypes.

Gonococcal Colony Typing.

Gonococcal colony typing is part a science and part an art that has been central to studies which have identified crucial virulence antigens and also demonstrated the ability of the bacteria to undergo rapid phase and antigenic variation. Without this fundamental work, modern molecular biological studies of gonococcal pathogenesis would not have been possible. Indeed colony typing is still essential when performing biological experiments with clinical and laboratory isolates and for monitoring their outcome. In this chapter, the methods for performing colony typing and techniques to optimize the process are described.

The research progress in protein-based pneumococcal vaccines

Streptococcus pneumoniae remains a leading cause of morbidity and mortality, especially among younger children and the elders. Streptococcus pneumococcus vaccines on the market have major disadvantages because of the limitation of serotypes. Therefore, it is an urgent need to develop an economic and broadly protective vaccines based on the bacterial proteins. The virulence factors and antigens expressed on the surface as potential candidates make a big progress. This review summarizes the components of protein-based pneumococcal vaccines in clinical trials, and the characteristics of the proteins, the protection in the infected animals and clinical trials. It will help readers to understand current status of protein-based pneumococcal vaccines. Key words: Streptococcus pneumoniae; Vaccine; Protein