Outer Membrane Protein Antigens Research Articles

Helicobacter pylori, persistent infection burden and structural brain imaging markers.

Persistent infections, whether viral, bacterial or parasitic, including Helicobacter pylori infection, have been implicated in non-communicable diseases, including dementia and other neurodegenerative diseases. In this cross-sectional study, data on 635 cognitively normal participants from the UK Biobank study (2006-21, age range: 40-70 years) were used to examine whether H. pylori seropositivity (e.g. presence of antibodies), serointensities of five H. pylori antigens and a measure of total persistent infection burden were associated with selected brain volumetric structural MRI (total, white, grey matter, frontal grey matter (left/right), white matter hyperintensity as percent intracranial volume and bi-lateral sub-cortical volumes) and diffusion-weighted MRI measures (global and tract-specific bi-lateral fractional anisotropy and mean diffusivity), after an average 9-10 years of lag time. Persistent infection burden was calculated as a cumulative score of seropositivity for over 20 different pathogens. Multivariable-adjusted linear regression analyses were conducted, whereby selected potential confounders (all measures) and intracranial volume (sub-cortical volumes) were adjusted, with stratification by Alzheimer's disease polygenic risk score tertile when exposures were H. pylori antigen serointensities. Type I error was adjusted to 0.007. We report little evidence of an association between H. pylori seropositivity and persistent infection burden with various volumetric outcomes (P > 0.007, from multivariable regression models), unlike previously reported in past research. However, H. pylori antigen serointensities, particularly immunoglobulin G against the vacuolating cytotoxin A, GroEL and outer membrane protein antigens, were associated with poorer tract-specific white matter integrity (P < 0.007), with outer membrane protein serointensity linked to worse outcomes in cognition-related tracts such as the external capsule, the anterior limb of the internal capsule and the cingulum, specifically at low Alzheimer's disease polygenic risk. Vacuolating cytotoxin A serointensity was associated with greater white matter hyperintensity volume among individuals with mid-level Alzheimer's disease polygenic risk, while among individuals with the highest Alzheimer's disease polygenic risk, the urease serointensity was consistently associated with reduced bi-lateral caudate volumes and the vacuolating cytotoxin A serointensity was linked to reduced right putamen volume (P < 0.007). Outer membrane protein and urease were associated with larger sub-cortical volumes (e.g. left putamen and right nucleus accumbens) at middle Alzheimer's disease polygenic risk levels (P < 0.007). Our results shed light on the relationship between H. pylori seropositivity, H. pylori antigen levels and persistent infection burden with brain volumetric structural measures. These data are important given the links between infectious agents and neurodegenerative diseases, including Alzheimer's disease, and can be used for the development of drugs and preventive interventions that would reduce the burden of those diseases.

Seroepidemiological survey of pathogenic Yersinia in domestic pigs in Chiba Prefecture, Japan.

This study aimed to investigate the prevalence of antibodies against pathogenic Yersinia such as Y. enterocolitica and Y. pseudotuberculosis in domestic pigs. A total of 650 serum samples from pigs in nine regions of the Chiba Prefecture in Japan, were tested using plasmid-encoded Yersinia outer membrane protein (Yops) antigen ELISA. The cutoff value was calculated using 20 pathogenic Yersinia-free pig serum samples. According to the cutoff value, 246 (37.8%) pigs from seven regions were considered seropositive for pathogenic Yersinia during the study period. These results indicate that pathogenic Yersinia is widespread in pigs in Chiba, which may become the source of human yersiniosis in this region.

Vaccinomics-aided next-generation novel multi-epitope-based vaccine engineering against multidrug resistant Shigella Sonnei: Immunoinformatics and chemoinformatics approaches.

Shigella sonnei is a gram-negative bacterium and is the primary cause of shigellosis in advanced countries. An exceptional rise in the prevalence of the disease has been reported in Asia, the Middle East, and Latin America. To date, no preventive vaccine is available against S. sonnei infections. This pathogen has shown resistances towards both first- and second-line antibiotics. Therefore, an effective broad spectrum vaccine development against shigellosis is indispensable. In the present study, vaccinomics-aided immunoinformatics strategies were pursued to identify potential vaccine candidates from the S. sonnei whole proteome data. Pathogen essential proteins that are non-homologous to human and human gut microbiome proteome set, are feasible candidates for this purpose. Three antigenic outer membrane proteins were prioritized to predict lead epitopes based on reverse vaccinology approach. Multi-epitope-based chimeric vaccines was designed using lead B- and T-cell epitopes combined with suitable linker and adjuvant peptide sequences to enhance immune responses against the designed vaccine. The SS-MEVC construct was prioritized based on multiple physicochemical, immunological properties, and immune-receptors docking scores. Immune simulation analysis predicted strong immunogenic response capability of the designed vaccine construct. The Molecular dynamic simulations analysis ensured stable molecular interactions of lead vaccine construct with the host receptors. In silico restriction and cloning analysis predicted feasible cloning capability of the SS-MEVC construct within the E. coli expression system. The proposed vaccine construct is predicted to be more safe, effective and capable of inducing robust immune responses against S. sonnei infections and may be worthy of examination via in vitro/in vivo assays.

Characterisation of the Putative Antigenic Genes of the Outer Membrane Proteins of Pasteurella multocida B:2 Strain PMTB2.1 through in silico Analysis

Outer membrane proteins (OMPs), usually found in Gram-negative bacteria, have long been shown to elicit immune responses in infected hosts. This tendency of OMPs to generate immune reactions makes them ideal candidates for vaccine development against pathogenic bacteria. Pasteurella multocida is a Gram-negative pathogen responsible for the economically significant veterinary disease, hemorrhagic septicemia (HS). HS is an endemic and highly fatal disease affecting buffaloes and cattle. In Malaysia, outbreaks of this disease cost about half a million USD each year. Thus, despite current treatment and prevention measures, HS is a prevalent issue that needs to be overcome. Pasteurella multocida subsp. multocida PMTB2.1, a Malaysian strain of the pathogen, has recently had its entire genome sequenced after being isolated from HS outbreaks in the region. Antigenic OMPs from this strain have since been identified and published for further characterisation. LptD, Wza, and TbpA are integral membrane proteins, while Pal is a peripheral membrane protein that has not been characterised in-depth. This study, therefore, aims to analyse these OMPs through in silico methods. First, protein homology modelling was performed using SWISS-MODEL, whereafter, the structures generated were validated using the SWISS-MODEL structure assessment page, PROCHECK, ERRAT, and PROSA programs. The Pal, Wza, and TbpA structures were good models, while the LptD structure was found to be a near-good model based on the validation performed. Analyses using BCPREDS, NetMHCpan4.1, and NetBoLAIIpan1.0 revealed that these four OMPs could potentially elicit humoral and cellular immune responses.

Prioritization of potential vaccine candidates and designing a multiepitope-based subunit vaccine against multidrug-resistant Salmonella Typhi str. CT18: A subtractive proteomics and immunoinformatics approach

Salmonella enterica serovar Typhi (S. Typhi), a causative agent of typhoid fever, is a Gram-negative, human-restricted pathogen that causes significant morbidity and mortality, particularly in developing countries. The currently available typhoid vaccines are not recommended to children below six years of age and have poor long-term efficacy. Due to these limitations and the emerging threat of multidrug-resistance (MDR) strains, the development of a new vaccine is urgently needed. The present study aims to design a multiepitope-based subunit vaccine (MESV) against MDR S. Typhi str. CT18 using a computational-based approach comprising subtractive proteomics and immunoinformatics. Firstly, we investigated the proteome of S. Typhi str. CT18 using subtractive proteomics and identified twelve essential, virulent, host non-homologous, and antigenic outer membrane proteins (OMPs) as potential vaccine candidates with low transmembrane helices (≤1) and molecular weight (≤110 kDa). The OMPs were mapped for cytotoxic T lymphocyte(CTL) epitopes, helper T lymphocyte (HTL) epitopes, and linear B lymphocyte (LBL) epitopes using various immunoinformatics tools and servers. A total of 6, 12, and 11 CTL, HTL, and LBL epitopes were shortlisted, respectively, based on their immunogenicity, antigenicity, allergenicity, toxicity, and hydropathicity potential. Four MESV constructs (MESVCs), MESVC-1, MESVC-2, MESVC-3, and MESVC-4, were designed by linking the CTL, HTL, and LBL epitopes with immune-modulating adjuvants, linkers, and PADRE (Pan HLA DR-binding epitope) sequences. The MESVCs were evaluated for their physicochemical properties, allergenicity, antigenicity, toxicity, and solubility potential to ensure their safety and immunogenic behavior. Secondary and tertiary structures of shortlisted MESVCs (MESVC-1, MESVC-3, and MESVC-4) were predicted, modeled, refined, validated, and then docked with various MHC I, MHC II, and TLR4/MD2 complex. Molecular dynamics (MD) simulation of the final selected MESVC-4 with TLR4/MD2 complex confirms its binding affinity and stability. Codon optimization and in silico cloning verified the translation efficiency and successful expression of MESVC-4 in E. coli str. K12. Finally, the efficiency of MESVC-4 to trigger an effective immune response was assessed by an in silico immune simulation. In conclusion, our findings show that the designed MESVC-4 can elicit humoral and cellular immune responses, implying that it may be used for prophylactic or therapeutic purposes. Therefore, it should be subjected to further experimental validations.

PRECLINICAL STUDIES AND CLINICAL TRIALS IN DETERMINATION OF SAFETY AND EFFICACY OF MENINGOCOCCAL VACCINES: PRESENT SCENARIO

Meningitis, a serious communicable inflammatory disease continues to be a worldwide threat especially in sub-Saharan Africa affecting millions of people with high death rates every year. Strains from six serogroups of the principal causative organism Neisseria meningitidis are found to be responsible for the majority of infections. Incidences of antibiotic resistance and efforts to provide mass protection have necessitated the development of meningococcal vaccines since the latter half of the 20th century. Aiming to ostracize meningitis by 2030, the World Health Organization focuses on vaccination as an important strategy to reach the goal. Due to limited efficacy and stability issues of earlier polysaccharide and protein conjugate vaccines respectively, outer membrane vesicle (OMV) vaccines were developed. Gene manipulations have also led to the development of more efficacious tailor-made OMV vaccines due to over-expression of antigenic outer membrane proteins along with lesser pyrogenicity. Available data from preclinical studies in animal models and clinical trials, on meningococcal vaccine candidates report the strength of immune response measured by serological tests such as enzyme-linked immunosorbent assay and serum bactericidal assay. Post-immunization adverse reactions have been also monitored as a part of safety assessment. The novelty of the present review lies in summarizing the outcomes of the preclinical animal studies and clinical trials conducted on various types of meningococcal vaccines till date and thereby highlighting the paucities in the existing information which can facilitate understanding the present scenario, challenges, and future scope in the field of meningococcal vaccine development.

A comparative evaluation of Typhidot and Widal tests for the detection of agglutinins against typhoid and paratyphoid bacilli in patients’ sera

Background: The term enteric fever includes typhoid fever caused by Salmonella typhi and paratyphoid fever caused by Salmonella paratyphi A, B, and C. Typhoid fever has been virtually eliminated in the developed countries during the past several decades, mainly as a result of improvement in water supply and sanitation, but it continues to be endemic in the resource-limited nations of the world. The control of paratyphoid fever has not been so successful. Bacteriological diagnosis of enteric fever consists of isolation of the bacilli from the patients and the demonstration of antibodies in their sera. Widal testing is cost-effective and gives reports quickly. The Typhidot test is based on the method of immunochromatography test. It is easy to perform, and the results can be preserved for a long time. This study aims to compare the sensitivity and specificity of the Widal test and Typhidot test for the diagnosis of enteric fever. Materials and Methods: This prospective study was carried out at the Department of Microbiology, N.C. Medical College and Hospital, Panipat, Haryana, India, over 6 months from September 2020 to February 2021. In our study, a total of 150 clinically suspected patients were included. First of all, the area for blood collection was cleaned with spirit-soaked cotton and 10 mL of blood was collected with a sterile disposable needle and syringe from a median cubital vein (antecubital vein) of each patient after obtaining informed consent from the patient (from parents in case of age below 18 years). Seven milliliters of blood was immediately transferred to a blood culture bottle by cleaning the cap of the bottle for isolation and identification of causative organisms and 3 mL was transferred to a sterile plain vial for serum separation. Then the qualitative Widal slide agglutination test and Typhidot test were performed on each sample. Results: In the present study, out of the 150 clinically suspected enteric fever cases, maximum positivity 53 (35.33%) was given by the Typhidot test, followed by 36 (24%) given by the qualitative Widal slide agglutination test and 44 (29.33%) given by blood culture for S. typhi and S. paratyphi. Conclusion: Our study highlights the use of Typhidot for early diagnosis of enteric fever and also cross-checks with Widal test and blood culture for the diagnosis of enteric fever. Typhidot tests are easy to perform and less-trained personnel can also perform the test; they have been designed to detect IgM and IgG antibodies to lipopolysaccharide or outer membrane protein antigens of S. typhi and S. paratyphi. It can be useful in the early diagnosis of infection in the initial weeks of primary infection when a single serum sample is available, with a sensitivity and specificity of 90% and 80%, respectively, considering blood culture as a gold standard.

Antigenic outer membrane proteins prediction of Pasteurella multocida serotype B:2

Outer membrane proteins (OMPs) are one of the prominent virulence factor or immunogenic element of Pasteurella multocida which are responsible for eliciting immune responses in multiple infected hosts. Identification of these proteins allows researchers to target OMPs to be manipulated as a vaccine against bacterial infection. Precise and rapid bioinformatics tools allow researchers to perform in silico analysis to extract putative OMPs from the genome information. In this study, we have successfully identified 105 putative OMPs of P. multocida subsp. multocida strain PMTB2.1 through computational prediction tools including a subcellular localisation predictor, PSORTb v3.0 followed by a lipoprotein predictor, LipoP 1.0 and a β-barrel transmembrane protein predictor, BOMP for sub-classification of the OMPs into 53 integral and 52 peripheral OMPs of this strain. The manipulation of antigenic epitope predictors and the antigenicity score filtering identified nine putative antigenic OMPs. These putative predicted antigenic OMPs of this pathogen will provide crucial initial guidance for the experimental identification and selection of antigenic protein(s) for the development of future haemorrhagic septicaemia (HS) vaccine.

Identifying the gaps in human and veterinary chlamydia vaccine development

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; Chlamydia infections in humans and animals pose a significant burden on health systems worldwide. While widespread screening, adequate treatment, and prevention programs are helpful to increase awareness and improve screening rates, infection rates are rising. A vaccine is necessary to slow increasing rates, manage negative consequences, and prevent possible antibiotic resistance. We present the current landscape regarding the innovations for commercial vaccine development in a “one-health” context.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; We developed a unique dataset containing data of patent documents intended for human and veterinary use, and clinical trials in order to provide a detailed description of the global chlamydia vaccine developments.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; Analysis of patents and clinical trials intended for human use presented a vaccine field that is underdeveloped, with no commercial human chlamydia vaccine available, and two potential candidates in a phase 1 clinical trial. Comparing innovations concerning chlamydia vaccine developments for both human and veterinary patents, it was clear that these fields are very different and independent of each other. The field is small, and certain companies and researchers show repeated interest. Partnerships among applicants and those involved in chlamydia vaccine innovation would be an important step to take towards innovating and developing an effective vaccine.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;We have shown that North America is considered, by patent application, to hold the most potential for a chlamydia vaccine, specifically against the &lt;em&gt;Chlamydia trachomatis &lt;/em&gt;strain. A new vaccine is likely to be a subunit vaccine with components of the major outer membrane protein antigen.&lt;/p&gt;

Development of a chlamydial vaccine for koalas : Protection against infection and disease

Abstract Wild koala populations continue to experience serious declines as a result of several threatening factors including, (i) loss of habitat, (ii) motor vehicle trauma; (iii) dog attacks; (iv) Chlamydia. Chlamydial infections are associated with diseases ranging from ocular disease leading to blindness, as well as urinary and genital tract disease, leading to female infertility. Modeling shows that targeting chlamydial disease would have a major impact on stabilising population decline. Our studies have demonstrated that koalas can be safely immunized with a vaccine containing a mixture of chlamydial major outer membrane protein (MOMP) antigens combined with a single dose subcutaneous regime. We conducted a wild koala field trial and observed strong, specific and long-lasting immune responses in the vaccinated koalas; high titre antibody responses (as measured by ELISA and also in vitro neutralisation) as well as Chlamydia-specific cytokine responses (interferon-gamma and IL-17 in particular). For animals which were Chlamydia PCR positive at the time of vaccination, we observed a significant reduction in their infection PCR load. We also observed protection from progression to clinical disease in the vaccinated animals. We also conducted a small trial to vaccinate animals which already have clinical signs of ocular disease. Instead of the normal practice of administering antibiotics (chloramphenicol, daily for 28 days, which severely disrupts the animal’s gut microbiome) we vaccinated four animals with a single dose, 3-MOMP vaccine. For all vaccinated animals, their Chlamydia PCR load decreased, and for 6 of the 7 animals, ocular disease regressed and the animals could be released back into the wild without further treatment.

Immunogenicity of an Adenoviral Vector Vaccine (rAd‐MOMP‐CpG) Against Chlamydia Trachomatis

Chlamydia trachomatis (C. trachomatis) infection is categorized as an important causes of sexually transmitted diseases in humans. Currently, there is no approved vaccine against C. trachomatis. This study was conducted to develop and evaluate the immunogenicity of a recombinant adenovirus (rAd‐MOMP‐CpG) vaccine against C. trachomatis in mice. The vaccine was constructed using adenovirus type 5 based on the major outer membrane protein (MOMP) antigen of C. trachomatis. Sixty mice were divided into 4 groups. In group 1, mice received rAd‐MOMP‐CpG (5×108 PFU) intranasal, 3 times at 2‐weeks intervals. Mice in groups 2, 3 and 4 received equivalent volume of adenovirus vector, CpG 1826, and PBS, respectively. Splenic cytokine levels and mRNA expression levels of IFNg and IL‐4 were determined by ELISA and qPCR, respectively. Furthermore, serum specific murine anti‐MOMP IgG levels were determined by quantitative ELISA. The constructed rAd‐MOMP‐CpG vaccine provoked a Chlamydia‐specific T helper type 1 response. There was a significant (P = 0.047) splenic IFNg stimulation in vaccinated group in comparison to the vector‐control group. The splenic IL‐4 expression remained at minimal stimulation levels across time points. In addition, the vaccine induced significant increase (P = 0.006) of delayed humoral anti‐MOMP IgG response compared to control groups. A recombinant adenovirus vaccine against C. trachomatis could provide important clues toward a vaccine development for C. trachomatis serovar protection in humans. However, further in vitro and in vivo studies are warranted to determine the most effective dosage, vaccine efficacy and safety.Support or Funding InformationJordan University of Science and Technology, Deanship of Research (grant number: 20140275).

Prediction of the Omp16 Epitopes for the Development of an Epitope-based Vaccine Against Brucellosis.

Brucellosis is an infectious disease caused by Brucella bacteria that cause disease in animals and humans. Brucellosis is one of the most common zoonotic diseases transmitted from animals-to-human through direct contact with infected animals and also consumption of unpasteurized dairy products. Due to the wide incidence of brucellosis in Iran and economical costs in industrial animal husbandry, Vaccination is the best way to prevent this disease. All of the available commercial vaccines against brucellosis are derived from live attenuated strains of Brucella but because of the disadvantage of live attenuated vaccines, protective subunit vaccine against Brucella may be a good candidate for the production of new recombinant vaccines based on Brucella Outer Membrane Protein (OMP) antigens. In the present study, comprehensive bioinformatics analysis has been conducted on prediction software to predict T and B cell epitopes, the secondary and tertiary structures and antigenicity of Omp16 antigen and the validation of used software confirmed by experimental results. The final epitope prediction results have proposed that the three epitopes were predicted for the Omp16 protein with antigenicity ability. We hypothesized that these epitopes likely have the protective capacity to stimulate both the B-cell and T-cell mediated immune responses and so may be effective as an immunogenic candidate for the development of an epitope-based vaccine against brucellosis.

Comparison of Nested Polymerase Chain Reaction and Real-Time Polymerase Chain Reaction Targeting 47kDa Gene for the Diagnosis of Scrub Typhus

AbstractIntroduction: Scrub typhus is a zoonotic infection caused by Orientia tsutsugamushi which is transmitted by Leptotrombidium mites. The disease manifests as a mild-to-severe illness with non-specific clinical symptoms. Rapid diagnosis and prompt treatment are essential for patient management. Both serological and molecular methods are used for the diagnosis of scrub typhus. The present study assessed the usefulness of detection of the gene encoding the 47kDa outer-membrane protein (OMP) for the laboratory diagnosis of scrub typhus. Materials and Methods: Nested polymerase chain reaction (nPCR) and real-time PCR targeting 47 kDa OMP antigen gene of O. tsutsugamushi were performed on ethylenediaminetetraacetic acid blood samples. Results: Six of the 103 (5.8%) patients showed the presence of 47kDa gene by nPCR. Seventy of 103 (67.9%) cases showed the presence of 47kDa gene by qPCR. Among the 70 positive cases, the majority of them were females (40/70, 57.1%). The highest number of positive cases was observed during October–February. Conclusion: Real-time PCR targeting O. tsutsugamushi-specific 47-kDa gene is more sensitive than nPCR and may be the assay of choice for the detection of the organism in patients with suspected scrub typhus.

Rickettsiae reservoirs among small mammals (Rats, Mice And Shrews) and their Arthropod Vectors in Sri Lanka

Rickettsioses are a group of emerging diseases caused by closely related bacteria. In Sri Lanka, to date, studies have been focused mainly on human subjects. The present study aimed to identify small mammal reservoir hosts and vectors of Rickettsia spp. and Orientia tsutsugamushi in two districts of Sri Lanka. Quantitative-PCR was carried out to detect Rickettsia using citrate synthase gene and Orientia using 47-kD outer membrane protein antigen gene in blood of small rodents and their infested ectoparasites. In both districts ~7.5% blood samples were positive for Rickettsia . Rattus rattus, Bandicota indica and Mus fernandoni were carriers. Three individuals of Suncus murinus, B. indica and Golunda ellioti had only infected ectoparasites. Copies of gltA/100 μL ranged from 133-1.2 × 10 4 in blood and 197-1.9 × 10 7 in ectoparasites. Of small mammals with ectoparasites, 43% had Rickettsia positive ectoparasites. Rhipicephalus haemaphysaloides, Ixodes ceylonensis, Haemaphysalis spinigera, Haemaphysalis spp., Stivalius aporus and Xenopsylla cheopis were positive. All study sites except three had infected small mammals or ectoparasites. All samples were negative for O. tsutsugamushi . This is the first study to report Rickettsia spp. in small mammals and their ectoparasites in Sri Lanka. Haemaphysalis spinigera , I. ceylonensis and S. aporus are new records of vectors for Rickettsia . This is also the first report of endemic M. fernandoni as a carrier of Rickettsia and G. ellioti with Rickettsia infected ectoparasites. Though rickettsiosis is not life threatening in most cases, it can lead to severe or fatal disease in vertebrate animals and humans. Hence, the knowledge of the distribution of said pathogen in the reservoirs is essential to control the disease.

Potential Outer Membrane Protein Candidates for Vaccine Development Against the Pathogen Vibrio anguillarum: A Reverse Vaccinology Based Identification.

Reverse vaccinology is a widely used approach that has facilitated the rapid identification of vaccine candidates suitable in vaccine development for pathogens. Vibrio anguillarum is a major pathogen responsible for vibriosis in fish and shellfish leading to huge economic losses to the aquaculture industry. Although commercial vaccines are available for fish against this bacterium they have their own limitations. In this study, we used the reverse vaccinology strategy to screen and identify V. anguillarum outer membrane proteins (OMPs) that could serve as vaccine candidates. Our analysis identified 23 antigenic outer membrane proteins which were highly conserved (>98% identity) across serovars of this bacterium. Of the 23, two were identified as outer membrane lipoproteins. Among the OMPs identified 18 were novel to this study and conserved across several Vibrio spp. with an identity of 21-93%. While the least (>48%) identity was observed for V. anguillarum ferrichrome-iron transporter protein, the highest identity (>80%) was seen for outer membrane proteins OmpK, BamA, OmpU, Fatty acid transporter, and two hypothetical proteins. These potential vaccine targets identified could contribute to the development of effective vaccine not only against V. anguillarum but also across other Vibrio spp. In addition, several B-cell and T-cell epitopes were predicted for the novel OMPs in this study which could aid in narrowing down peptide selection in designing a suitable epitope-based vaccine.

Outer membrane proteins analysis of Shigella sonnei and evaluation of their antigenicity in Shigella infected individuals.

Bacillary dysentery caused by infection with Shigella spp. remains as serious and common health problem throughout the world. It is a highly multi drug resistant organism and rarely identified from the patient at the early stage of infection. S. sonnei is the most frequently isolated species causing shigellosis in industrialized countries. The antigenicity of outer membrane protein of this pathogen expressed during human infection has not been identified to date. We have studied the antigenic outer membrane proteins expressed by S. sonnei, with the aim of identifying presence of specific IgA and IgG in human serum against the candidate protein biomarkers. Three antigenic OMPs sized 33.3, 43.8 and 100.3 kDa were uniquely recognized by IgA and IgG from patients with S. sonnei infection, and did not cross-react with sera from patients with other types of infection. The antigenic proteome data generated in this study are a first for OMPs of S. sonnei, and they provide important insights of human immune responses. Furthermore, numerous prime candidate proteins were identified which will aid the development of new diagnostic tools for the detection of S. sonnei.

Increased Immunogenicity and Protective Efficacy of a P. aeruginosa Vaccine in Mice Using an Alum and De-O-Acylated Lipooligosaccharide Adjuvant System.

Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogen that commonly causes fatal infections in cystic fibrosis and burn patients as well as in patients who are hospitalized or have impaired immune systems. P. aeruginosa infections are difficult to treat owing to the high resistance of the pathogen to conventional antibiotics. Despite several efforts, no effective prophylactic vaccines against P. aeruginosa are currently available. In this study, we investigated the activity of the CIA06 adjuvant system, which is composed of alum and de-O-acylated lipooligosaccharide, on a P. aeruginosa outer membrane protein (OMP) antigen vaccine in mice. The results indicated that CIA06 significantly increased the antigen-specific IgG titers and opsonophagocytic activity of immune sera against P. aeruginosa. In addition, the antibodies induced by the CIA06-adjuvanted vaccine exhibited higher cross-reactivity with heterologous P. aeruginosa strains. Finally, mice immunized with the CIA06-adjuvanted vaccine were effectively protected from lethal P. aeruginosa challenge. Based on these data, we suggest that the CIA06 adjuvant system might be used to promote the immunogenicity and protective efficacy of the P. aeruginosa OMP vaccine.

Development of Brucellosis Vaccine Based on Determinant Antigenic of Outer Membrane Protein (OMP) 36 kDa From Brucella abortus Local Isolate

Brucellosis is a disease that can be prevented through vaccination. Yet, the effectiveness of the vaccination to fight this disease is considered weak. Fortunately, attempts to modify brucellosis vaccine is still keep going. Some brucellosis vaccines have been found and developed in the past time such as the vaccine B.abortus strain 19-BA and 104M which was made from weakened microbes which had been widely used in Uni Soviet and China. The other brucellosis vaccine that were used in the past were the phenolinsoluble peptidoglycan vaccine which was made in France and polysaccharideprotein vaccine which was used in Russia. This research attempted to see the determinant of antigenic Outer Membrane Protein (OM) 36 kDa Brucella abortus local isolation which has immunogenic character to be developed as an advanced brucellosis vaccine. The method used in this research was the Omp2 gene of Brucella abortus of local isolate employed the PCR technique. The result of the PCR was then sequenced to analyze the determinant antigenic and the bounding prediction of either the T cell or the B cell which were responsible for immune response. The result of this study showed that the gen Omp2 which encoded the OMP 36 kDa Brucella abortus of local isolation with primary JPF 5’ GCG CTC AGG CTG CCG ACG CAA 3’ and JPR 5’ CAT TGC GGT CGG TAC CGG AG 3’ targeted the gene 162 bp, was then translated into amino acids to be later undergo the in silico test using Kolaskar and Tongaonkar Antigenicity Prediction method. The epitope prediction resulted were MSRVCDAYGAGYFYI and TETCLRVHGYVRYD. The result of the epitope prediction of MSRVCDAYGAGYFYI showed that there was a bond with MHC I in YGAGYFYI of the 8th amino acid series to the 15th series, while the epitope prediction of TETCLRVHGYVRYD showed that there was a bond to the ETCLRVHGY of the series of amino acids number 2 to 10. Bond with MHC II existed in the amino acid series of MSRVCDAYGAGYFYI, while the bond with the B cells existed in BCSAYGA and CLRVHG amino acid series. This research has been successful in predicting the epitope of the OMP 36 kDa Brucella abortus of local isolate which had immunogenic characteristic for its ability to bond with the MHC I, MHC II and B cells.

Immunogenic properties of outer membrane protein of Acinetobacter baumannii that loaded on chitosan nanoparticles

This study aimed to prepare an experimental nano vaccine for Acinetobacter baumannii. In current study, Acinetobacter isolates were identified by growth onto CHROMagarTM Acinetobacter/MDR and standard biochemical tests. Identification of isolates of Acinetobacter isolates to species level was done by VITEK 2 compact system and API20. Chitosan nanoparticles was used in this study as an adjuvant, the results showed chitosan a perfect adjuvant because it carried outer membrane protein antigen and stimulates an immune response at treated rats, use of Chitosan nanoparticles as a carrier to OMP increased the concentration of cytokines (IL-2,IL-6,IFN-ƴ), antibody titer, total leukocytes and differential leukocytes in treated rats compared with each control group and OMP group

Design and characterization of plasmids encoding antigenic peptides of Aha1 from Aeromonas hydrophila as prospective fish vaccines

The current investigation aimed at designing DNA vaccines against Aeromonas hydrophila infections. The DNA vaccine candidates were designed to express two antigenic outer membrane protein (Aha1) peptides and to be delivered by a nanoparticle-based delivery system. Gene sequences of conserved regions of antigenic Aha1 [aha1(211–381), aha1(211–381)opt, aha1(703–999) and aha1(703–999)opt] were cloned into pVAX-GFP expression vector. The selected DNA vaccine candidates were purified from E. coli DH5α and transfected into Chinese hamster ovary cells. The expression of the antigenic peptides was measured in cells along post-transfection time, through the fluorescence intensity of the reporter GFP. The lipofection efficiency of aha-pVAX-GFP was highest after 24h incubation. Formulated PLGA-chitosan nanoparticle/plasmid DNA complexes were characterized in terms of size, size distribution and zeta potential. Nanocomplexes with average diameters in the range of 150–170nm transfected in a similar fashion into CHO cells confirmed transfection efficiency comparable to that of lipofection. DNA entrapment and further DNase digestion assays demonstrated ability for pDNA protection by the nanoparticles against enzymatic digestion.