Major Immunogenic Protein Research Articles

Genomic Analysis of Aeromonas salmonicida ssp. salmonicida Isolates Collected During Multiple Clinical Outbreaks Supports Association with a Single Epidemiological Unit.

Outbreaks of furunculosis cause significant losses in salmonid aquaculture worldwide. With a recent rise in antimicrobial resistance, regulatory measures to minimize the use of antibiotics in animal husbandry, including aquaculture, have increased scrutiny and availability of veterinary medical products to control this disease in production facilities. In such a regulatory environment, the utility of autogenous vaccines to assist with disease prevention and control as a veterinary-guided prophylactic measure is of high interest to the producers and veterinary services alike. However, evolving concepts of epidemiological units and epidemiological links need to be considered during approval and acceptance procedures for the application of autogenous vaccines in multiple aquaculture facilities. Here, we present the results of solid-state nanopore sequencing (Oxford Nanopore Technologies, ONT) performed on 54 isolates of Aeromonas salmonicida ssp. salmonicida sampled during clinical outbreaks of furunculosis in different aquaculture facilities from Bavaria, Germany, from 2017 to 2020. All of the performed analyses (phylogeny, single nucleotide polymorphism and 3D protein modeling for major immunogenic proteins) support a high probability that all studied isolates belong to the same epidemiological unit. Simultaneously, we describe a cost/effective method of whole genome analysis with the usage of ONT as a viable strategy to study outbreaks of other pathogens in the field of aquatic veterinary medicine for the purpose of developing the best autogenous vaccine candidates applicable to multiple aquaculture establishments.

Evaluation of the protective efficacy of six major immunogenic proteins of Mycoplasma Synoviae.

Mycoplasma synoviae (MS) is a primary avian pathogen prevalent worldwide that causes airsacculitis and synovitis in birds. Vaccination is recommended as the most cost-effective strategy in the control of MS infection. Novel alternative vaccines are needed for eradicating and controlling MS infection in flocks. DnaK, enolase, elongation factor Tu (EF-Tu), MSPB, NADH oxidase and LP78 are the major immunogenic antigens of MS and are promising targets for subunit vaccine candidates. In the present study, genes encoding DnaK, enolase, EF-Tu, MSPB, LP78, and NADH oxidase were cloned and expressed in Escherichia coli. Enzyme-linked immunosorbent assay showed that the six recombinant proteins were recognized by convalescent sera, indicating that they were expressed during infection. Two injections of the six subunit vaccines induced a robust antibody response and increased the concentrations of IFN-γ and IL-4, especially rEnolase and rEF-Tu. The proliferation of peripheral blood lymphocytes was enhanced in all of the immunized groups. Chickens immunized with rEnolase, rEF-Tu, rLP78, and rMSPB conferred significant protection against MS infection, as indicated by significantly lower DNA copies in the trachea, lower scores of air sac lesions, and lesser tracheal mucosal thickness than that in the challenge control. Especially, rEnolase provided the best protective efficacy, followed by rEF-Tu, rMSPB, and rLP78. Our finds demonstrate that the subunit vaccines and bacterin can only reduce the lesions caused by MS infection, but not prevent colonization of the organism. Our findings may contribute to the development of novel vaccine agents against MS infection.

Effect of the ati Gene Deletion on the Pathogenicity and Immunogenicity of the Vaccinia Virus.

Among the nonvirion proteins of the vaccinia virus (VACV), a 94-kDa long protein is most abundantly present; the protein is a truncated form of the 150-kDa A-type inclusion (ATI) protein of the cowpox virus encoded by the ati gene. This VACV protein does not form intracellular ATIs, being as it is a major immunogen upon infection/immunization of humans or animals with the VACV. Antibodies specific to this protein are not virus-neutralizing. The present study focused on the effect of the production of this nonstructural major immunogenic VACV protein on the manifestation of pathogenicity and immunogenicity of the virus in the BALB/c mouse model of infection. In order to introduce a targeted deletion into the VACV LIVP genome, the recombinant integration/deletion plasmid pΔati was constructed and further used to generate the recombinant virus LIVPΔati. The pathogenicity of the VACV LIVP and LIVPΔati strains was studied in 3-week-old mice. The mice were intranasally infected with the viruses at a dose of 107 pfu; 50% of the animals infected with the parent LIVP strain died, while infection with the LIVPΔati strain led to the death of only 20% of the mice. Intradermal vaccination of mice aged 6- weeks with the LIVPΔati virus statistically significantly increased the production of VACV-specific IgG, compared to that after intradermal vaccination with VACV LIVP. Meanwhile, no differences were noted in the cell-mediated immune response to the vaccination of mice with VACV LIVP or LIVPΔati, which was assessed by ELISpot according to the number of splenocytes producing IFN-γ in response to stimulation with virus-specific peptides. Intranasal infection of mice with lethal doses of the cowpox virus or the ectromelia virus on day 60 post-immunization with the studied VACV variants demonstrated that the mutant LIVPΔati elicits a stronger protective response compared to the parent LIVP.

Chicken infectious anemia virus (CIAV) VP1 antagonizes type I interferon (IFN-I) production by inhibiting TBK1 phosphorylation

Chicken infectious anemia virus (CIAV) infection induces immunosuppression or subclinical immunosuppression in chickens. CIAV infection has been reported to repress type I interferon (IFN-I) expression, but the underlying mechanisms are not yet understood. Here we reported that VP1, the capsid protein of CIAV, the major immunogenic protein that triggers the production of neutralizing antibodies in chickens, inhibited type I interferon (IFN-I) expression induced by cGAS-STING signaling. We showed that VP1 inhibited TBK1 phosphorylation and down stream signal transduction, leading to the inhibition of IFN-I expression. Subsequently, we demonstrated that VP1 interacted with TBK1. Finally, we clarified that aa 120–150 in VP1 was essential for VP1 to interact with TBK1 and inhibit cGAS-STING signaling. These findings will help us further understand the pathogenesis of CIAV in chickens.

Comparative evaluation of the diagnostic potential of two major core proteins of goatpox virus expressed in the prokaryotic system

Members of the genus capripoxvirus (CaPV) encode more than 100 putative proteins and CaPV ORF 095 and 103 genes encode two major immunogenic core proteins that are partly exposed to the host immune system. In this study, full-length genes of these two core proteins of goatpox virus (GTPV) were over-expressed in E. coli BL21-codonPlus (DE3)-RIPL strain using pET32a vector and purified under denaturing conditions and characterized by SDS-PAGE. Expressed proteins were confirmed as 37 kDa (ORF 095) and 39 kDa (ORF 103) proteins in western blot. Both the proteins have shown a good immunoreactivity with anti-GTPV and -SPPV antibodies in optimized ELISA and they did not show any cross-reactivity with other viruses of sheep and goats. However, the ORF095 protein has shown better reactivity than ORF103 to a standard known positive serum when tested in optimized ELISA. Therefore, capripoxvirus-specific rORF095 alone or in combination with other CaPV proteins has the immense potential in developing ELISA as a coating antigen for sero-evaluation of capripox in sheep and goats.

Structural basis of Omicron immune evasion: A comparative computational study

BackgroundThe vaccines used against SARS-CoV-2 by now have been able to develop some neutralising antibodies in the vaccinated population and their effectiveness has been challenged by the emergence of the new strains with numerous mutations in the spike protein of SARS-CoV-2. Since S protein is the major immunogenic protein of the virus which contains Receptor Binding Domain (RBD) that interacts with the human Angiotensin-Converting Enzyme 2 (ACE2) receptors, any mutations in this region should affect the neutralisation potential of the antibodies leading to the immune evasion. Several variants of concern of the virus have emerged so far, amongst which the most critical are Delta and recently reported Omicron. In this study, we have mapped and reported mutations on the modelled RBD and evaluated binding affinities of various human antibodies with it. MethodDocking and molecular dynamics simulation studies have been used to explore the effect of mutations on the structure of RBD and RBD-antibody interaction. ResultsThese analyses show that the mutations mostly at the interface of a nearby region lower the binding affinity of the antibody by ten to forty percent, with a downfall in the number of interactions formed as a whole. It implies the generation of immune escape variants. ConclusionsNotable mutations and their effect was characterised that explain the structural basis of antibody efficacy in Delta and a compromised neutralisation effect for the Omicron variant. Thus, our results pave the way for robust vaccine design that can be effective for many variants.

Synthetic SARS-CoV-2 Spike-Based DNA Vaccine Elicits Robust and Long-Lasting Th1 Humoral and Cellular Immunity in Mice.

The ongoing global pandemic of coronavirus disease 2019 (COVID-19) calls for an urgent development of effective and safe prophylactic and therapeutic measures. The spike (S) glycoprotein of severe acute respiratory syndrome-coronavirus (SARS-CoV-2) is a major immunogenic and protective protein and plays a crucial role in viral pathogenesis. In this study, we successfully constructed a synthetic codon-optimized DNA-based vaccine as a countermeasure against SARS-CoV-2, denoted VIU-1005. The design was based on a codon-optimized coding sequence of a consensus full-length S glycoprotein. The immunogenicity of the vaccine was tested in two mouse models (BALB/c and C57BL/6J). Th1-skewed systemic S-specific IgG antibodies and neutralizing antibodies (nAbs) were significantly induced in both models 4 weeks after three injections with 100 μg of the VIU-1005 vaccine via intramuscular needle injection but not intradermal or subcutaneous routes. Such immunization induced long-lasting IgG and memory T cell responses in mice that lasted for at least 6 months. Interestingly, using a needle-free system, we showed an enhanced immunogenicity of VIU-1005 in which lower or fewer doses were able to elicit significantly high levels of Th1-biased systemic S-specific immune responses, as demonstrated by the significant levels of binding IgG antibodies, nAbs and IFN-γ, TNF and IL-2 cytokine production from memory CD8+ and CD4+ T cells in BALB/c mice. Furthermore, compared to intradermal needle injection, which failed to induce any significant immune response, intradermal needle-free immunization elicited a robust Th1-biased humoral response similar to that observed with intramuscular immunization. Together, our results demonstrate that the synthetic VIU-1005 candidate DNA vaccine is highly immunogenic and capable of inducing long-lasting Th1-skewed humoral and cellular immunity in mice. Furthermore, we show that the use of a needle-free system could enhance the immunogenicity and minimize doses needed to induce protective immunity in mice, supporting further preclinical and clinical testing of this candidate vaccine.

Mucosal Delivery of Recombinant Vesicular Stomatitis Virus Vectors Expressing Envelope Proteins of Respiratory Syncytial Virus Induces Protective Immunity in Cotton Rats.

Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract (LRT) infections, with increased severity in high-risk human populations, such as infants, the immunocompromised, and the elderly. Although the virus was identified more than 60 years ago, there is still no licensed vaccine available. Over the years, several vaccine delivery strategies have been evaluated. In this study, we developed two recombinant vesicular stomatitis virus (rVSV) vector-based vaccine candidates expressing the RSV-G (attachment) protein (rVSV-G) or F (fusion) protein (rVSV-F). All vectors were evaluated in the cotton rat animal model for their in vivo immunogenicity and protective efficacy against an RSV-A2 virus challenge. Intranasal (i.n.) delivery of rVSV-G and rVSV-F together completely protected the lower respiratory tract (lungs) at doses as low as 103 PFU. In contrast, doses greater than 106 PFU were required to protect the upper respiratory tract (URT) completely. Reimmunization of RSV-immune cotton rats was most effective with rVSV-F. In immunized animals, overall antibody responses were sufficient for protection, whereas CD4 and CD8 T cells were not necessary. A prime-boost immunization regimen increased both protection and neutralizing antibody titers. Overall, mucosally delivered rVSV-vector-based RSV vaccine candidates induce protective immunity and therefore represent a promising immunization regimen against RSV infection.IMPORTANCE Even after decades of intensive research efforts, a safe and efficacious RSV vaccine remains elusive. Expression of heterologous antigens from rVSV vectors has demonstrated several practical and safety advantages over other virus vector systems and live attenuated vaccines. In this study, we developed safe and efficacious vaccine candidates by expressing the two major immunogenic RSV surface proteins in rVSV vectors and delivering them mucosally in a prime-boost regimen. The main immune parameter responsible for protection was the antibody response. These vaccine candidates induced complete protection of both the upper and lower respiratory tracts.

The Outer Membrane Proteins OmpA, CarO, and OprD of Acinetobacter baumannii Confer a Two-Pronged Defense in Facilitating Its Success as a Potent Human Pathogen.

Of all the ESKAPE pathogens, carbapenem-resistant and multidrug-resistant Acinetobacter baumannii is the leading cause of hospital-acquired and ventilator-associated pneumonia. A. baumannii infections are notoriously hard to eradicate due to its propensity to rapidly acquire multitude of resistance determinants and the virulence factor cornucopia elucidated by the bacterium that help it fend off a wide range of adverse conditions imposed upon by host and environment. One such weapon in the arsenal of A. baumannii is the outer membrane protein (OMP) compendium. OMPs in A. baumannii play distinctive roles in facilitating the bacterial acclimatization to antibiotic- and host-induced stresses, albeit following entirely different mechanisms. OMPs are major immunogenic proteins in bacteria conferring bacteria host-fitness advantages including immune evasion, stress tolerance, and resistance to antibiotics and antibacterials. In this review, we summarize the current knowledge of major A. baumannii OMPs and discuss their versatile role in antibiotic resistance and virulence. Specifically, we explore how OmpA, CarO, and OprD-like porins mediate antibiotic and amino acid shuttle and host virulence.

Analysis of Immunogenicity of Acanthopanax senticosus Injection

The cause of the immunogenicity of Acanthopanax senticosus injection has been studied. The method used for the preparation of the injection includes boiling the plant material in water, precipitation with ethanol, and filtration to produce the extract. In the current study, this extract was treated with saturated ammonium sulfate to collect the protein from the extract. Indicators of systemic allergy, including total immunoglobulin (IgE), interleukin -4 (IL-4), and interferon-gamma (IFN-γ) levels in the antiserum of Guinea pigs sensitized with this protein extract were used to determine the immunogenicity of the protein extract. Testing was performed using Western blotting to identify IgE in antiserum binding in Guinea pigs sensitized by injection. The target protein band was further identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry. The protein extract from A. senticosus caused positive reactions and significantly increased the levels of total IgE, IL-4, and IFN-γ in the serum of sensitized Guinea pigs. Western blotting showed that a group of proteins with a molecular weight of 60 000 in the A. senticosus protein extract acted as the major immunogenic protein by binding to serum IgE of Guinea pigs sensitized with A. senticosus injection. The protein was a pyruvate kinase homologous protein with high sequence similarity to the pyruvate kinase protein of Vitis vinifera. It was concluded that the allergic reaction caused by the injection of A. senticosus may be related to the interaction of these macromolecular proteins within the body.

Identification of structure proteins of cyprinid herpesvirus 2

Cyprinid herpesvirus 2 (CyHV-2) is the causative agent of herpesviral hematopoietic necrosis (HVHN). In order to identify the protein contained the genome of CyHV-2, virus particles were purified by sucrose density gradient in combination with ultracentrifugation and observed by transmission electron microscope. The viral proteins were separated by SDS-PAGE, and then identified by mass spectrometry identification. The anti-CyHV-2 polyclonal antibody prepared by immunizing mice with purified virus was subjected to Western blotting analysis and mass spectrometry identification to identify the major immunogenic proteins to mice. A large number of intact CyHV-2 virions were collected from the sucrose layer between 50% and 66%, and a small amount of viral envelops were damaged. The results of mass spectrometry identification showed that CyHV-2 containing 74 proteins, including 3 capsid proteins, 18 membrane proteins, 53 other proteins; Western blotting and mass spectrometry identification showed that there are eight major immunogenic proteins, namely pORF92, pORF115, pORF25, pORF57, pORF66, pORF72, pORF131 and pORF132. This study is the first to identify the proteins contained in CyHV-2 as well as the major immunogenic proteins, which will provide a more comprehensive theoretical and practical basis for the in-depth study of CyHV -2 virus.

Soluble FMDV VP1 proteins fused with calreticulin expressed in Escherichia coli under the assist of trigger factor16 (Tf16) formed into high immunogenic polymers

Foot and mouth disease virus (FMDV) is a highly contagious pathogen propagating among cloven-hoofed animals. As a major immunogenic protein, VP1 plays a pivotal role in the induction of neutralizing antibodies, which therefore is an ideal target for developing subunit vaccines. In current study, four prokaryotic expression clones (rV4C, rC4V, rV5F and rF5V) were constructed by fusing truncated calreticulin (CRT) (120–250 aa or 120–308 aa) at the N/C terminal of vp1 gene, and co-expressed with chaperone trigger factor 16 (Tf16) in E.coli, respectively. The soluble recombinant CRT-fused VP1 proteins could form into homogeneous reactive polymers with average hydrodynamic diameters around 100 nm according to the dynamic light scattering (DLS) data. Immunization of guinea pigs with 10 μg purified CRT-fused VP1 proteins induced high levels of antibodies against naked-VP1 through indirect ELISA. Sandwich ELISA showed that only rC4V could elicit the same level of antibody against FMD virus as commercial inactivated vaccine after booster. The lymphocyte cytokines secretion of immunized rC4V was higher than the other CRT-fused VP1 proteins in guinea pigs. These results showed that the soluble CRT-fused VP1 proteins, especially rC4V, expressed with Tf16 in E. coli might have potential to be used as subunit vaccine candidate against FMDV.

Emergence of a Novel Ehrlichia minasensis Strain, Harboring the Major Immunogenic Glycoprotein trp36 with Unique Tandem Repeat and C-Terminal Region Sequences, in Haemaphysalis hystricis Ticks Removed from Free-Ranging Sheep in Hainan Province, China.

Ehrlichia minasensis, a recently described Ehrlichia species that is the most closely related to, but clearly distinct from, Ehrlichia canis, has been circulating in not only bovines, cervids, and dogs but also several tick species from Canada, Brazil, France, Pakistan, Ethiopia, and Israel. However, there are no reports of E. minasensis in China. The purpose of this study was to explore whether E. minasensis is present naturally in ticks in China. Through PCR targeting of the genus-conserved dsb gene, E. minasensis DNA was detected in Haemaphysalis hystricis ticks removed from free-ranging sheep in Hainan Province, South China in 2017. The partial sequence of the dsb, 16S rRNA, and groEL genes demonstrated that the Hainan strain shared 99% identity with the dsb gene of E. minasensis strain UFMG-EV (GenBank: JX629808), with the 16S rRNA of E. minasensis isolate E-2650 (MH500005) and with the groEL gene of E. minasensis strain UFMG-EV (JX629806), respectively. Moreover, sequence analysis of the major immunogenic tandem repeat protein (trp36) revealed that the Hainan strain harbored a unique tandem repeat sequence (APEAAPVSAPEAAPVSAPVS) and a C-terminal region that differed from those of other known E. minasensis strains. Additionally, phylogenetic analysis based on the entire amino acid sequence of trp36 revealed that the Hainan strain was closely related to a recently described E. minasensis strain from Brazil, of which the sister clade contained different strains of E. canis. The discovery of this novel Hainan strain in H. hystricis ticks represents the first known natural presence of E. minasensis in South China, highlighting the need for its constant surveillance.

Region-Based Epitope Prediction, Docking and Dynamic Studies of OMP31 as a Dominant Antigen in Human and Sheep Brucella

Brucella is an important zoonotic pathogen which causes significant commercial loss in industry and considerable disease in livestock and human. Diminishing fertility and also abortion in animal and Malta fever disease in human. In spite of some successful vaccines against animal brucellosis, no satisfactory vaccine has been produced against human brucellosis. Accordingly, OMP31 as a major immunogenic and immunodominant protein in Brucella melitensis has been used to predict substantial epitopes against human and/or sheep MHCII alleles in three different continents (America, Oceania, and Europe) through bioinformatics tools. In order to validate region-based projections, the accuracy of epitopes was assessed by Vaxijen, an online server. The structure of these peptides was predicted through PEP-FOLD server. Predicted epitopes were sifted through docking studies with relevant MHCII receptors and finally, docked complexes were evaluated by molecular dynamic simulations. According to the frequency of human and sheep alleles in different regions, “FGTVRARLG” and “YIGINAGYA” epitopes can be considered for American, Eastern European, and Asian human populations and also sheep flocks of Australia and New Zealand (Corriedale breed), United States (Polypay and Rumbouillet breeds) and France (Rambouillet breed). Besides, “AINNNWTLKSE”, “FLESKVNFH”, “VLGAETDFQG”, and YIGINAGYA can be significant in American and northern Indian human populations and also sheep of France (Suffolk and Columbia breeds), England and Scotland (Cheviot breed) and United States (Polypay breed). Eventually, “AINNNWTLKSE” and “VQAGYNWQL” might be important in American human and Britannia (Scottish Blackface breed), United States (Columbia, Rambouillet, and Polypay breeds) and French (Rambouillet breed) sheep populations.

Enhanced protective immune response to PCV2 adenovirus vaccine by fusion expression of Cap protein with InvC in pigs.

The major immunogenic protein capsid (Cap) of porcine circovirus type 2 (PCV2) is critical to induce neutralizing antibodies and protective immune response against PCV2 infection. This study was conducted to investigate the immune response of recombinant adenovirus expressing PCV2b Cap and C-terminal domain of Yersinia pseudotuberculosis invasin (Cap-InvC) fusion protein in pigs. The recombinant adenovirus rAd-Cap-InvC, rAd-Cap and rAd were generated and used to immunize pigs. The phosphate-buffered saline was used as negative control. The specific antibodies levels in rAd-Cap-InvC and ZJ/C-strain vaccine groups were higher than that of rAd-Cap group (p < 0.05), and the neutralization antibody titer in rAd-Cap-InvC group was significantly higher than those of other groups during 21–42 days post-immunization (DPI). Moreover, lymphocyte proliferative level, interferon-γ and interleukin-13 levels in rAd-Cap-InvC group were increased compared to rAd-Cap group (p < 0.05). After virulent challenge, viruses were not detected from the blood samples in rAd-Cap-InvC and ZJ/C-strain vaccine groups after 49 DPI. And the respiratory symptom, rectal temperature, lung lesion and lymph node lesion were minimal and similar in the ZJ/C-strain and rAd-Cap-InVC groups. In conclusion, our results demonstrated that rAd-Cap-InvC was more efficiently to stimulate the production of antibody and protect pigs from PCV2 infection. We inferred that InvC is a good candidate gene for further development and application of PCV2 genetic engineering vaccine.

Porcine endogenous retrovirus envelope coated baculoviral DNA vaccine against porcine reproductive and respiratory syndrome virus

PERV is a major virus concerning xenotransplantation study. However, the interesting part is that PERV is present in all kinds of pigs without pathogenicity and immune response. Furthermore, since pig cells have receptors for PERV, the gene delivery system using PERV envelope is highly likely to develop into an excellent viral vector in pigs. We developed a recombinant baculovirus with a modified surface for expressing the porcine endogenous retrovirus (PERV) envelope. Porcine reproductive and respiratory syndrome virus (PRRSV) infection is a severe concern in the porcine industry due to reproduction failure and respiratory symptoms. GP5 and M proteins are major immunogenic proteins of PRRSV. Using PERV-modified baculovirus (Ac mPERV) as a delivery vector, we constructed a dual antigen (GP5 and M)-encoding DNA vaccine system, Ac mPERV-C5/C6. Intramuscular immunization in mice and pigs, Ac mPERV-C5/C6 induced comparative high humoral and cellular immune responses. Our results support further development of Ac mPERV-C5/C6 as a potential PRRSV vaccine in the porcine industry. In addition, the Ac mPERV system may be applied to the generation of other effective DNA vaccines against porcine viral diseases.

Enhanced protective immunity to CSFV E2 subunit vaccine by using IFN-γ as immunoadjuvant in weaning piglets

The glycoprotein E2 of classical swine fever virus (CSFV) is a major immunogenic protein that induces neutralizing antibodies and protective immunity. Thus, E2 is a suitable target antigen for the development of genetically engineered CSFV vaccines. However, these vaccines cannot generate complete protective immunity in their hosts, thereby limiting the scope of applications under field conditions. IFN-γ is an immune adjuvant that has been shown to enhance antigen immune response in various experimental models. In this study, porcine IFN-γ was used to improve the immunogenicity of the CSFV E2 subunit vaccine in pigs. Pigs were immunized with E2 subunit vaccine alone or in combination with IFN-γ. Results demonstrated that porcine IFN-γ did not enhance the CSFV-specific antibody and neutralizing antibody titers compared with the E2 subunit vaccine alone. However, co-administration of the E2 and IFN-γ subunit vaccines significantly enhanced the CSFV-specific IFN-γ expression. These findings indicated that porcine IFN-γ can increase cellular immune responses to E2 protein in pigs. Furthermore, co-immunization with E2 + IFN-γ subunit vaccine and C-strain conferred complete protection against CSFV. In contrast, E2 subunit vaccines provided incomplete protection in pigs. These results indicated that using IFN-γ as an adjuvant with CSFV E2 subunit vaccines can enhance the specific protective immune response. Therefore, E2 + IFN-γ subunit vaccine is a promising marker vaccine candidate for the control and eradication of CSF.

Protective efficacy of a DNA vaccine encoding capsid protein of porcine circovirus-like virus P1 against porcine circovirus 2 in mice.

The capsid protein is the major immunogenic protein of porcine circovirus 2 (PCV2). The nucleotide sequence of porcine circovirus-like virus P1 shares high homology with open reading frame (ORF) 2 of PCV2, and ORF1 of P1 encodes its structural protein. Mice were vaccinated twice intramuscularly with a plasmid expressing the P1 ORF1 protein (pcDNA3.1(+)-ORF1) at 2-week intervals. All animals vaccinated with pcDNA3.1(+)-ORF1 developed higher specific anti-P1 antibody levels, and had less PCV2 viremia and milder histopathological changes than PCV2-challenged mice in the control group. Our results show that the P1 DNA vaccine elicited immune responses against PCV2 infection in a mouse model.

Identification and characterization of a novel B-cell epitope on Aleutian Mink Disease virus capsid protein VP2 using a monoclonal antibody

Aleutian mink disease is caused by a highly contagious parvovirus (Aleutian mink disease virus, AMDV). This disease is one of the most commercially important infectious disease worldwide and causes considerable economic losses to mink farmers. The capsid protein VP2 is the major immunogenic antigenic protein of AMDV, and is involved in viral tropism, pathogenicity, and host selection. However, few reports have described the use of VP2-specific monoclonal antibodies (mAbs) in B-cell epitope identification and immunological detection. In this study, we produced a specific mAb, 1G5, against AMDV VP2 protein (amino acids: 200 ∼ 588) and characterized its specificity and relative affinity. Six partially overlapping truncated recombinant proteins and seven synthetized peptides were used to identify the epitopes recognized by 1G5. The results indicate that mAb 1G5 can distinguish AMDV, MEV and CPV2 with high affinity (Ka = 5.37 × 109), and the minimal linear epitope is located in amino acid residues 459EEEGWPAASGTHFED473. Sequence alignments demonstrated that the linear epitope was completely conserved among most Amdoparvoviruses except the bat parvovirus, where three substitutions (463W-463F, 466A-466G and 471F-471Y) were noted. Our results reveal that the identified epitope might be a common B-cell epitope of AMDV antibodies, and the 1G5 mAb can be used to identify the cleavage of the capsid proteins during AMDV infection. This is also the first report of a B-cell epitope on AMDV capsid protein VP2 (VP2: 459–473) using a mAb. These findings have potential applications in the development of new diagnostic tools for AMDV.

Insights Into Onchocerca volvulus Population Biology Through Multilocus Immunophenotyping.

We have developed a serologically based immunophenotyping approach to study Onchocerca volvulus (Ov) population diversity. Using genomic sequence data and polymerase chain reaction-based genotyping, we identified nonsynonymous single-nucleotide polymorphisms (SNPs) in the genes of 16 major immunogenic Ov proteins: Ov-CHI-1/Ov-CHI-2, Ov16, Ov-FAR-1, Ov-CPI-1, Ov-B20, Ov-ASP-1, Ov-TMY-1, OvSOD1, OvGST1, Ov-CAL-1, M3/M4, Ov-RAL-1, Ov-RAL-2, Ov-ALT-1, Ov-FBA-1, and Ov-B8. We assessed the immunoreactivity of onchocerciasis patient sera (n = 152) from the Americas, West Africa, Central Africa, and East Africa against peptides derived from 10 of these proteins containing SNPs. Statistically significant variation in immunoreactivity among the regions was seen in SNP-containing peptides derived from 8 of 10 proteins tested: OVOC1192(1-15), OVOC9988(28-42), OVOC9225(320-334), OVOC7453(22-36), OVOC11517(14-28), OVOC3177(283-297), OVOC7911(594-608), and OVOC12628(174-188). Our data show that differences in immunoreactivity to variant antigenic peptides may be used to characterize Ov populations, thereby elucidating features of Ov population biology previously inaccessible because of the limited availability of parasite material.