Divalent Vaccine Research Articles

Design of multi-epitope chimeric vaccine against Monkeypox virus and SARS-CoV-2: A vaccinomics perspective.

The current era we experience is full with pandemic infectious agents that no longer threatens the major local source but the whole globe. Almost the most emerging infectious agents are severe acute respiratory syndrome coronavirus-2 (SARS CoV-2), followed by monkeypox virus (MPXV). Since no approved antiviral drugs nor licensed active vaccines are yet available, we aimed to utilize immunoinformatics approach to design chimeric vaccine against the two mentioned viruses. This is the first study to deal with design divalent vaccine against SARS-CoV-2 and MPXV. ORF8, E and M proteins from Omicron SARS-CoV-2 and gp182 from MPXV were used as the protein precursor from which multi-epitopes (inducing B-cell, helper T cells, cytotoxic T cells and interferon-ɣ) chimeric vaccine was contrived. The structure of the vaccine construct was predicted, validated, and docked to toll-like receptor-2 (TLR-2). Moreover, its sequence was also used to examine the immune simulation profile and was then inserted into the pET-28a plasmid for in silico cloning. The vaccine construct was probable antigen (0.543) and safe (non-allergen) with strong binding energy to TLR-2 (-1169.8 kcal/mol) and found to have significant immune simulation profile. In conclusion, the designed chimeric vaccine was potent and safe against SARS-CoV-2 and MPXV, which deserves further consideration.

A novel chimeric vaccine candidate for porcine reproductive and respiratory syndrome virus (PRRSV) I and II elicits neutralizing antibodies against both types.

Porcine reproductive and respiratory syndrome virus (PRRSV) is an economically important virus within the swine industry. The virus causes respiratory disease and reproductive failure. Two species of PRRSV-I and II are co-dominant, yet no effective vaccination strategy has been developed to protect against these two types. With an aim to develop a chimeric vaccine strain to protect against both types, in this study, a chimeric porcine reproductive and respiratory syndrome virus (PRRSV) type I and II was rescued using reverse genetics for the first time. Four chimeric infectious clones were designed based on the genomic arrangement of the structural proteins. However, only the clone carrying the transcriptional regulatory sequence (TRS) and ORF6 of a PRRSV-I and ORF6 of a PRRSV-II generated a viable recombinant virus, suggesting that concurrent expression of ORF6 from both parental viruses is essential for the recovery of type I and II chimeric PRRSV. The chimeric virus showed significantly lower replication ability than its parental strains in vitro, which was improved by serial passaging. In vivo, groups of pigs were inoculated with either the chimeric virus, one of the parental strains, or PBS. The chimeric virus replicated in pig tissue and was detected in serum 7 days post-inoculation. Serum neutralization tests indicated that pigs inoculated with the chimeric virus elicited neutralizing antibodies that inhibited infection with strains of both species and with greater coverage than the parental viruses. In conclusion, the application of this technique to construct a chimeric PRRSV holds promise for the development of a highly effective modified live vaccine candidate. This is particularly significant since there are currently no approved commercial divalent vaccines available to combat PRRSV-I and II co-infections.

Development of measures in the field of veterinary and sanitary requirements for the safety of herd horse breeding products

Infectious diseases such as salmonellosis, strangles and rhinopneumonia of horses remain an unsolved task of veterinary practice not only in the Republic of Sakha (Yakutia), but also in other regions of Russia where herd horse breeding is developed. Only in recent years, after scientists of the Yakut Research Institute of Agriculture have developed highly immunogenic vaccines such as "Salmonella abortion vaccine", "Inactivated horse strangles vaccine" and at the approval stage "Divalent vaccine against rhinopneumonia and equine salmonellosis", "Combined vaccine against rhinopneumonia and strangles horse for young horses", epizootological the situation in the republic. In the process of introducing these vaccines in disadvantaged farms, the quality of horse meat and foal supplied is assessed by conducting organoleptic, physico-chemical, microbiological, chemical-toxicological and radiological studies. All studies were conducted in compliance with standards and norms. Enzyme immunoassay proved the circulation of the rhinopneumonia virus in farms where vaccinations were not carried out. Salmonella abortion and horse strangles are registered annually in the republic. Infectious diseases create a barrier to the export of horse breeding products. We are developing a scheme of preventive veterinary and sanitary measures for horse breeding farms of the republic that are disadvantaged by infectious diseases of horses. One of its important points is to improve the quality of products obtained from horse breeding. During the implementation of these measures, mares and young horses were immunized with vaccines developed by us in the farms of Tattinsky, Megino-Kangalassky and Ust-Aldansky uluses. Vaccinated animals received the probiotic "Sakhabactisubtil" with food. The business output of foals from vaccinated mares increased by 10-30%. A veterinary and sanitary examination of the foal was carried out. Microbiological examination of 50 samples of meat in 2 samples revealed bacteria of the Escherichia coli group. According to other indicators, the studied meat samples correspond to TR CU 021/2011 "On food safety", TR CU 034/2013 "On the safety of meat and meat products". Export of foals from the republic is possible after recovery from rhinopneumonia and annual vaccination against salmonella abortion and horse strangles.

Specificity of DNA Vaccines against the Genogroup J and U Infectious Hematopoietic Necrosis Virus Strains Prevalent in China.

Infectious hematopoietic necrosis virus (IHNV) is the most important pathogen threatening the aquaculture of salmonid fish in China. In addition to the common genogroup J IHNV, genogroup U has been newly discovered in China. However, there is no effective DNA vaccine to fight against this emerging genogroup U IHNV in China. In this study, DNA vaccines encoding the IHNV viral glycoprotein (G) gene of the GS2014 (genogroup J) and BjLL (genogroup U) strains isolated from northern China were successfully developed, which were identified by restriction analysis and IFA. The expression of the Mx-1 gene and G gene in the spleens and muscles of the injection site as well as the titers of the serum antibodies were measured to evaluate the vaccine efficacy by RT-qPCR and ELISA. We found that DNA vaccine immunization could activate Mx1 gene expression and upregulate G gene expression, and the mRNA levels of the Mx1 gene in the muscles were significantly higher than those in the spleens. Notably, DNA vaccine immunization might not promote the serum antibody in fish at the early stage of immunization. Furthermore, the efficacy of the constructed vaccines was tested in intra- and cross-genogroup challenges by a viral challenge in vivo. It seemed that the DNA vaccines were able to provide great immune protection against IHNV infection. In addition, the genogroup J IHNV-G DNA vaccine showed better immune efficacy than the genogroup U IHNV-G or divalent vaccine, which could provide cross-immune protection against the genogroup U IHNV challenge. Therefore, this is the first study to construct an IHNV DNA vaccine using the G gene from an emerging genogroup U IHNV strain in China. The results provide great insight into the advances of new prophylactic strategies to fight both the genogroup J and U IHNV in China.

Preclinical Establishment of a Divalent Vaccine against SARS-CoV-2.

First-generation vaccines against SARS-CoV-2 do not provide adequate immune protection. Therefore, we engineered a divalent gene construct combining the receptor-binding domain (RBD) of the spike protein and the immunodominant region of the viral nucleocapsid. This fusion protein was produced in either E. coli or a recombinant baculovirus system. Subsequently, the fusion protein was mixed with adjuvant and administered to mice in a prime-booster mode. Mice (72%) produced an IgG response against both proteins (titer: 10−4–10−5) 14 days after the first booster injection, which was increased to 100% by a second booster. Comparable IgG responses were detected against the delta, gamma and omicron variants of the RBD region. Durability testing revealed IgGs beyond 90 days. In addition, cytolytic effector cell molecules were increased in lymphocytes isolated from peripheral blood. Ex vivo stimulation of T cells by nucleocapsid and RBD peptides showed antigen-specific upregulation of CD44 among the CD4+ and CD8+ T cells of vaccinated mice. No side effect was documented in the central nervous system. Cumulatively, these data represent a proof-of-principle approach alternative to existing mRNA vaccination strategies.

Development of Klebsiella pneumoniae Capsule Polysaccharide-Conjugated Vaccine Candidates Using Phage Depolymerases.

Klebsiella pneumoniae is an important pathogen associated with nosocomial infection and has developed increasing resistance to antibiotics such as extended-spectrum β-lactams and carbapenem. In recent years, K. pneumoniae isolates have emerged as a major cause of global community-acquired infections such as pneumonia and pyogenic liver abscess. Although serotypes K1 and K2 have been identified as the predominant capsular types associated with invasive infections, no K. pneumoniae vaccine is commercially available, probably due to immunogenicity loss in the traditional depolymerization method to obtain capsule polysaccharide (CPS) for the preparation of conjugated vaccine. In this study, we successfully retained immunogenicity by using K1 (K1-ORF34) and K2 (K2-ORF16) CPS depolymerases that were identified from phages to cleave K1 and K2 CPSs into intact structural units of oligosaccharides with intact modifications. The obtained K1 and K2 oligosaccharides were separately conjugated with CRM197 carrier protein to generate CPS-conjugated vaccines. Immunization experiments of mice showed both K1 and K2 CPS-conjugated vaccines induced anti-CPS antibodies with 128-fold and 64-fold increases of bactericidal activities, respectively, compare to mice without vaccinations. Challenge tests indicated that K1 or K2 CPS-conjugated vaccine and divalent vaccine (a mixture of K1 and K2 CPS-conjugated vaccines) protected mice from subsequent infection of K. pneumoniae by the respective capsular type. Thus, we demonstrated K1 and K2 CPS-conjugated vaccines prepared by CPS depolymerases is a promising candidate for developing vaccines against human K. pneumoniae infections.

Persistence of vaccine immunity against canine parvovirus and canine distemper virus for determination of vaccine protocol in dogs: impacts and challenges in Brazil

Vaccine protocols were established for dogs and cats, considering the circulating period of maternal antibodies from the puppies, the type of antigen used to make the vaccines and the vaccine immunity duration. This study aimed to approach the duration of vaccine immunity against the canine parvovirus (CPV-2) and the canine distemper virus (CDV), as determining factor to choose the adequate vaccine protocol, besides to stand out the main implications found in Brazil that difficult the application of these current protocols, as the technical challenges to use them. For that, this article described some information about the types of current vaccines, the immunity duration against the CPV-2 and CDV, as well the respective vaccine protocols that were applied. The searches were done in the database of PubMed, SciELO, Google Scholar, Capes Journals and academic books, by the following keywords: vaccination guidelines; humoral immune response; vaccination strategy; distemper; parvovirus infection; and duration of vaccine immunity. Considering the facts, it is understood that the annual revaccination against the CPV-2 and CDV for dogs must be individually assessed, because the vaccine immunity has an average duration of three years, that is, the best alternative for the animal would be the application of routine serological tests, aiming to assess if the antibodies titration remains protective. Another alternative is the use of divalent or trivalent vaccines.

Evaluation of immunogenicity and protection mediated by Lawsonia intracellularis subunit vaccines

Lawsonia intracellularis is an economically important bacterium that causes ileitis in pigs. Current vaccines for L. intracellularis do not allow for differentiation between infected and vaccinated animals (DIVA), which is beneficial for disease tracking and surveillance. Previously, we identified five putative surface L. intracellularis proteins that were targeted by antibodies from pigs infected with L. intracellularis which could serve as antigens in a subunit vaccine. We conducted two trials to determine whether these antigens were immunogenic and provided protection against infectious challenge and whether truncated glycoprotein D could be used as a DIVA antigen. For Trial 1, 5 week-old piglets were administered intramuscular monovalent vaccines comprised of a recombinant (r) flagella subunit protein (rFliC,) and DIVA antigen (truncated glycoprotein D (TgD), a herpes virus antigen) both formulated with a combination adjuvant consisting of polyinosinic:polycytidylic acid(poly I:C), host defense peptide 1002 and polyphosphazene, referred to as Triple Adjuvant (TriAdj). Relative to control animals, animals vaccinated with rFliC and rTgD had significantly elevated antigen-specific humoral immunity in sera suggesting that rFliC and TgD are immunogenic. Control animals had negligible anti-TgD titres suggesting that TgD may be a suitable DIVA antigen for pigs. For Trial 2, piglets were immunized with a trivalent vaccine (FOG vaccine consisting of rFLiC, rOppA protein (a ABC Type dipeptide transport system) and rGroEL (a stress response protein)) and a divalent vaccine (CM vaccine consisting of rClpP (an ATP-dependent Clp protease proteolytic subunit) and rMetK (a S-adenosyl methionine synthase)) formulated with Emulsigen®. Relative to the control pigs, pigs immunized with the FOG vaccine produced robust and significantly higher serum IgG antibodies against rFliC and rGroEL, and significantly higher anti-FliC and anti-GroEL IgA antibodies in jejunal (GroEL only) and ileal intestinal mucosa. Pigs immunized with CM vaccine produced significantly higher serum antibodies against rClpP and rMetK and significantly higher anti-rClpP IgA antibodies in the ileum relative to the control pigs. Quantitative polymerase chain reaction (qPCR) analysis showed that 18 days after challenge with infectious L. intracellularis, challenged/control pigs and pigs that received the CM vaccine, but not the pigs vaccinated with the FOG vaccine, shed significantly more bacteria in feces than the unchallenged controls pigs. These data suggest that the FOG vaccinated pigs showed limited protection. While promising, more work is needed to enhance the efficiency of the intramuscular vaccine to show significant disease protection.

Distribution of human papillomavirus genotypes in western China and their association with cervical cancer and precancerous lesions.

The aim of this study was to describe the distribution of human papillomavirus (HPV) genotypes among cervical cancers and pre-cancers in Shaanxi province of western China. A total of 17,341 women who were screened for cervical cancer from January 2014 to December 2016, using HPV genotyping and ThinPrep cytologic test were included. The prevalence and attribution of HPV genotypes were stratified by cervical lesion and age group. Of the subjects, 26.3% were infected with HPV, 28.0% of whom had multiple infections. The crude HPV prevalence increased from atypical squamous cells of undetermined significance/low-grade squamous intraepithelial lesions (ASCUS/LSIL, 64.3%) to high-grade squamous intraepithelial lesions (HSIL, 79.8%) and to invasive cervical cancer (ICC, 89.7%, P < 0.001). The three most prevalent genotypes were HPV 16 (8.0%), 58 (4.2%), and 52 (4.0%), and HPV 16, 31 and 33 were positively correlated with increased severity of cervical lesions. Additionally, the divalent vaccine genotypes HPV 16 and 18 accounted for 68.2% of ICC cases. Although 78.5% of ICC and 60.3% of HSIL cases were attributed to 9-valent vaccine genotypes, the other genotypes not covered by any vaccine still resulted in increases in coverage, with 1.5% for ICC, 5.3% for HSIL, and 13.5% for ASCUS/LSIL. HPV prevalence in western China was consistent with other regions of China. Early vaccination with 9-valent HPV vaccine is recommended in this locality for females younger than 26 years with no prior infection, while divalent the vaccine is more appropriate for women between 26 and 45 years, considering the efficacy, safety and cost-effectiveness of vaccines.

Clinical Analysis of Human Papillomavirus Infection Types Distribution in Tissues of Cervical Squamous Cell Carcinoma

In this article, we investigated prevalence and distributed types of human papillomavirus (HPV) among female cervical squamous cell carcinoma patients in eastern China (mainly in Jiangsu Province). Tissue samples of total 1021 cases with cervical squamous cell carcinoma were incurred from female patients passing through biopsy or surgery. HPV DNA and genotypes of all subjects were examined using polymerase chain reaction (PCR) and gene-chip. There were 937 positive cases among 1021 cervical squamous cell carcinoma tissue samples with the total HPV infection rate of 91.77%. The HPV infection rate of single type was 75.42%. The predominant types of single infection with HPV were HPV 16 (52.60%), HPV 18 (5.19%), HPV 58 (4.51%), HPV 52 (2.84%), HPV 31 (2.74%), HPV 33 (2.45%), HPV 59 (1.76%) and HPV 45 (0.88%). The HPV infection rate of multiple types was 16.35%. The predominant types of multiple infection with HPV were HPV 16+18 (19.16%), 16+58 (6.59%),16+52 (5.99%), 16+33 (5.39%), 11+16 (2.99%), 16+31 (2.99%), 16+45 (2.99%), 16+42 (2.40%) and 16+59 (2.40%). Cervical squamous cell carcinomas had a close relationship with HPV infection. HPV 16, 18, 58, 52, 31, 33, 59, 45 with high prevalence in the cervical squamous cell carcinoma deserve great attention in eastern China (mainly in Jiangsu Province). The protection spectrum of divalent vaccine and ninevalent vaccine were, respectively, 68.52% (642/937) and 90.82% (851/937) in the cases of cervical squamous cell carcinomas.

Abstract C116: High-risk HPV screening and typing shows high co-infection rate and potential for low vaccine coverage in a low- and middle-income country

Abstract Introduction. Cervical cancer is almost always a result of infection with a high risk human papillomavirus (hrHPV) of which there are 14 different types. This type of cancer is prevalent in low- and middle-income countries (LMICs) where screening programs for pre- or invasive cervical cancer by Pap test or visual inspection with ascetic acid are limited in scope as is local expertise in evaluating Pap smears. Since 2006, a HPV vaccine protecting against hrHPV types 16 and 18 has been recommended by the WHO, and through the GAVI Alliance, is provided to some fractions of populations in more than 70 countries. A newer and more expensive vaccine protects again 9 types of HPV A broader spectrum 9-valent vaccine released in 2014 protects against HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58. Preventing cervical cancer by vaccination against HPV is considered to be a promising strategy. Materials and Methods. In three separate studies, we implemented molecular screening for hrHPV from cervical swab specimens, providing access to pre-cancer testing for women from several regions of Honduras, which is ranked the poorest country in the northern hemisphere. We screened 2,645 women from two rural regions and an urban region of Honduras. In the final study of 1725 Honduran factory workers, we substituted a large-capacity rice cooker for a standard laboratory hotplate to accelerate laboratory throughput for DNA extraction. A DNA-based multi-color melt curve analysis by PCR followed, and we were able to rapidly screen for all 14 hrHPV types. Results. Across all three studies, there was an average hrHPV positivity prevalence of 22%. The most common types of hrHPV found in each study were as follows: Study 1 hrHPV types 16, 31, 58, 59, and 68; Study 2 hrHPV types 16, 39, 52, 58, and 68; and Study 3 were hrHPV types 16, 35, 58, 63, and 64 were the most common. Among those infected with a hrHPV type, 18% had co-infections with multiple hrHPV types. Based on these results, the vast majority of infected women would not have been protected by the divalent HPV vaccine and a significant proportion of women would still not be protected by the multivalent vaccine, which does not cover the hrHPV types 35, 39, 52, 59, 63, 64, 88 found in these samples. Conclusions. Cervical cancer remains a prevalent and deadly disease in LMICs. Our studies examining the prevalence of hrHPV types in several different regions of Honduras identified high prevalence rates of viral types not targeted by commercially available vaccines. These findings suggest that vaccination programs alone should not be considered complete coverage against cervical cancer-causing high-risk HPV, and that further location-specific testing of cervical tissue for hrHPV typing is warranted. Citation Format: Aaron E Atkinson, Carlos Alberto Matute Mandujano, Suyapa Bejarano, Linda S Kennedy, Gregory J Tsongalis. High-risk HPV screening and typing shows high co-infection rate and potential for low vaccine coverage in a low- and middle-income country [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr C116.

Simultaneous Immunization with Omp25 and L7/L12 Provides Protection against Brucellosis in Mice.

Currently used Brucella vaccines, Brucella abortus strain 19 and RB51, comprises of live attenuated Brucella strains and prevent infection in animals. However, these vaccines pose potential risks to recipient animals such as attenuation reversal and virulence in susceptible hosts on administration. In this context, recombinant subunit vaccines emerge as a safe and competent alternative in combating the disease. In this study, we formulated a divalent recombinant vaccine consisting of Omp25 and L7/L12 of B. abortus and evaluated vaccine potential individually as well as in combination. Sera obtained from divalent vaccine (Omp25+L7/L12) immunized mice group exhibited enhanced IgG titers against both components and indicated specificity upon immunoblotting reiterating its authenticity. Further, the IgG1/IgG2a ratio obtained against each antigen predicted a predominant Th2 immune response in the Omp25+L7/L12 immunized mice group. Upon infection with virulent B. abortus 544, Omp25+L7/L12 infected mice exhibited superior Log10 protection compared to individual vaccines. Consequently, this study recommends that simultaneous immunization of Omp25 and L7/L12 as a divalent vaccine complements and triggers a Th2 mediated immune response in mice competent of providing protection against brucellosis.

Results testing the efficiency of divalent vaccine against Rhinopneuvmonia and Salmonella abortion of horses

Results testing the efficiency of divalent vaccine against Rhinopneuvmonia and Salmonella abortion of horses

A built-in adjuvant-engineered mucosal vaccine against dysbiotic periodontal diseases

Periodontitis is associated with a dysbiotic shift in the oral microbiome. Vaccine approaches to prevent microbial shifts from healthy to diseased state in oral biofilms would provide a fundamental therapeutic strategy against periodontitis. Since dental plaque formation is a polymicrobial and multilayered process, vaccines targeting single bacterial species would have limited efficacy in clinical applications. In this study, we developed a divalent mucosal vaccine consisting of a mixture of FlaB-tFomA and Hgp44-FlaB fusion proteins targeting virulence factors of inflammophilic bacteria Fusobacterium nucleatum and Porphyromonas gingivalis, respectively. Introduction of peptide linkers between FlaB and antigen improved the stability and immunogenicity of engineered vaccine antigens. The intranasal immunization of divalent vaccine induced protective immune responses inhibiting alveolar bone loss elicited by F. nucleatum and P. gingivalis infection. The built-in flagellin adjuvant fused to protective antigens enhanced antigen-specific antibody responses and class switch recombination. The divalent vaccine antisera recognized natural forms of surface antigens and reacted with diverse clinical isolates of Fusobacterium subspecies and P. gingivalis. The antisera inhibited F. nucleatum-mediated biofilm formation, co-aggregation of P. gingivalis and Treponema denticola, and P. gingivalis-host cell interactions. Taken together, the built-in adjuvant-engineered mucosal vaccine provides a technological platform for multivalent periodontitis vaccines targeting dysbiotic microbiome.

Effectiveness of a divalent Streptococcus dysgalactiae inactivated vaccine in cobia (Rachycentron canadum L.)

Streptococcus dysgalactiae is a major concern in cobia (Rachycentron canadum) cultured in Taiwan; however, there have been no reports on vaccines against this pathogen. This study considered the immune response and protective efficacies of a S. dysgalactiae-derived inactivated vaccine in this fish species. Streptococcus dysgalactiae isolate SD49, belonging to the predominant PFGE pulsotype S1A1, in which 86% of isolates have been classified and SD12 being the highest virulent strain were two vaccine candidates chosen for this study. The bacterin vaccine using a mixture of these two isolates was safe and immunized fish induced greater lysozyme, phagocytosis activities, and antibody responses. Notably, the vaccine protected cobia from the highest virulent S. dysgalactiae strain with a 100% relative percentage survival when challenged 6 weeks post primary vaccination. Together, the divalent vaccine could stimulate immune responses and effectively protect cobia against S. dysgalactiae infection.

Recombinant Hsp33 and OmpC protein can serve as promising divalent vaccine with protection against Vibrio anguillarum and Edwardsiella tarda in flounder (Paralichthys olivaceus)

Vibrio anguillarum and Edwardsiella tarda are severe aquaculture pathogens shared similar epidemiological characteristics and susceptible to flounder (Paralichthys olivaceus). In our previous studies, recombinant(r) protein heat shock protein 33 (rHsp33) from V. anguillarum and outer membrane protein C (rOmpC) from E. tarda were proved to have protection against V. anguillarum and E. tarda, respectively. In this paper, the cross protection of rHsp33 against E. tarda and rOmpC against V. anguillarum, and the protection of divalent vaccine candidate (rHsp33 + rOmpC, rHC) against both V. anguillarum and E. tarda were evaluated. RHC, rHsp33, and rOmpC were vaccinated to flounder, respectively, and the percentages of surface immunoglobulin-positive (sIg+) cells in peripheral blood lymphocytes (PBLs), serum IgM, specific antibodies against V. anguillarum or E. tarda, specific antibodies against rHsp33, rOmpC or rHC, the expression of immune-related genes and relative percent survival (RPS) against V. anguillarum or E. tarda were measured. The results showed that: RHC could induced the enhancement of sIg + cells and high levels of specific antibodies against both V. anguillarm and E. tarda; Also a significant increase of specific antibodies against rHsp33, rOmpC or rHC, and up-regulation of gene expression of CD3, CD4-1, CD4-2, CD8α, CD8β and IgM in spleen, head-kidney, and hindgut, RPS of 70 ± 3.45% against V. anguillarum and 60 ± 1.48% against E. tarda, respectively. In addition, rHsp33 induced specific antibodies against E. tarda and rOmpC, and had a RPS of 43.3 ± 3.73% against E. tarda; rOmpC could evoke specific antibodies against V. anguillarum and rHsp33, and had a RPS of 44 ± 1.27% against V. anguillarm; The results demonstrated that there was cross protection of rHsp33 against E. tarda and rOmpC against V. anguillarum, rHC as a divalent vaccine can induce significant immune response and efficient protection against both E. tarda and V. anguillarum in flounder.

Immunogenicity and Safety of a Chemically Synthesized Divalent Group A Streptococcal Vaccine.

Background Group A streptococcus (GAS) infections and poststreptococcal sequelae remain a health problem worldwide, which necessitates searching for an effective vaccine, while no licensed GAS vaccine is available. We have developed a divalent peptide vaccine composed of 84 amino acids to cover the main GAS serotypes (M1 and M12 streptococci) in China, and herein, we aimed to evaluate immunogenicity and safety of this vaccine. Methods Mice were immunized with the vaccine. ELISA, indirect bactericidal test, and immunofluorescent assay were used to study immunogenicity. GAS challenge assay was used to test the protective effect. Safety was tested by histopathological analysis. Results Immunized group mice (n=16) developed higher titer antibody after immunization than nonimmunized group mice (n=16) did. This antibody can deposit on the surface of GAS and promote killing of GAS, resulting in 93.1% decrease of M1 GAS and 89.5% of M12 GAS. When challenged with M1 and M12 streptococci, immunized group mice had a higher survival rate (87.5% and 75%) than nonimmunized group mice (37.5% and 25%). No autoimmune reactions were detected on organs of mice. Conclusion The results suggest that this vaccine shows fair immunogenicity and safety, which will lead our research on GAS vaccine into clinical trial.

The prevalence of HPV infections in HPV-vaccinated women from the general population.

Currently, three prophylactic HPV vaccines are commercially available to prevent HPV 16/18 infection and associated lesions. The aim of the study was to assess markers of HPV infection in women/girls before vaccination and to ascertain the prevalence and spectrum of post-vaccination HPV types. Three hundred and thirty subjects of which 75 were virgins were enrolled. Before the first dose of the HPV vaccine and 1, 3 and 5 years after the completion of HPV vaccination, the samples for cytology, HPV detection and anti-HPV antibody response were taken. At enrolment, HPV DNA was detected in 38% of sexually active girls/women. At the first, second and third follow-up, HPV DNA was found in 40, 45, and 39% of them. The seroprevalence rates to HPV 6, 11, 16 and 18 in these subjects were 31, 21, 18 and 10%. On the follow-up significantly higher levels of antibodies to HPV 16/18 were found after application of divalent vaccine. Results of the study demonstrate high prevalence of HPV infection in young women. In a substantial number of women, HPV-specific antibodies as well as high-risk HPV types were detected. HPV-specific antibodies were also frequently found in non-sexually active girls. The acquisition of HPV after the onset of sexual life was very fast.

WITHDRAWN: Generation of Divalent DNA Vaccine Based on p39 Gene of Brucella melitensis and shiga-like toxin 2 (stx2) Gene of Escherichia coli

WITHDRAWN: Generation of Divalent DNA Vaccine Based on p39 Gene of Brucella melitensis and shiga-like toxin 2 (stx2) Gene of Escherichia coli

Optimization and Characterization of Candidate Strain for Coxsackievirus A16 Inactivated Vaccine.

Coxsackievirus A16 (CA16) and enterovirus 71 (EV71), both of which can cause hand, foot and mouth disease (HFMD), are responsible for large epidemics in Asian and Pacific areas. Although inactivated EV71 vaccines have completed testing in phase III clinical trials in Mainland China, CA16 vaccines are still under development. A Vero cell-based inactivated CA16 vaccine was developed by our group. Screening identified a CA16 vaccine strain (CC024) isolated from HFMD patients, which had broad cross-protective abilities and satisfied all requirements for vaccine production. Identification of the biological characteristics showed that the CA16CC024 strain had the highest titer (107.5 CCID50/mL) in Vero cells, which would benefit the development of an EV71/CA16 divalent vaccine. A potential vaccine manufacturing process was established, including the selection of optimal time for virus harvesting, membrane for diafiltration and concentration, gel-filtration chromatography for the down-stream virus purification and virus inactivation method. Altogether, the analyses suggested that the CC-16, a limiting dilution clone of the CC024 strain, with good genetic stability, high titer and broad-spectrum immunogenicity, would be the best candidate strain for a CA16 inactivated vaccine. Therefore, our study provides valuable information for the development of a Vero cell-based CA16 or EV71-CA16 divalent inactivated vaccine.