OBJECTIVE: The present study aimed to evaluate the immunogenicity of BA.2 variant receptor binding domain (RBD) recombinant protein formulated with CpG 1826 plus alum dual adjuvant. METHODS: The BA.2 variant RBD (residues 308-548) fusing TT-P ₂ epitope was obtained from prokaryotic expression system, purification technology and dialysis renaturation, which was designated as Sot protein. The soluble Sot protein formulated with CpG 1826 plus alum dual adjuvant was designated as Sot/CA subunit vaccine and then the BALB/c mice were intramuscularly administrated with two doses of the Sot/CA subunit vaccine at 14-day interval (day 0 and 14). On day 28, the number of effector T lymphocytes secreting IFN-γ and IL-4 in mice spleen were determined by enzyme-linked immunospot (ELISpot) assay. The serum IgG, IgG1 and IgG2a antibodies were examined by enzyme-linked immunosorbent assay (ELISA). In addition, the level of neutralizing antibodies (NAbs) induced by Sot/CA subunit vaccine was also evaluated by the microneutralization assay. RESULTS: The high-purity soluble Sot protein with antigenicity was successfully obtained by the prokaryotic expression, protein purification and dialysis renaturation. The Sot/CA subunit vaccine induced a high level of IgG antibodies and NAbs, which were of cross-neutralizing activity against SARS-CoV-2 BA.2 and XBB.1.5 variants. Meanwhile, Sot/CA subunit vaccine also induced a high level of effector T lymphocytes secreting IFN-γ (635.00 ± 17.62) and IL-4 (279.20 ± 13.10), respectively. Combined with a decreased IgG1/IgG2a ratio in the serum, which indicating Sot/CA subunit vaccine induced a Th1-type predominant immune response. CONCLUSION The Sot protein formulated with CpG 1826 plus alum dual adjuvant showed that the excellent cellular and humoral immunogenicity, which provided a scientific basis for the development of BA.2 variant subunit vaccines and references for the adjuvant application of subunit vaccines.
Animals ; COVID-19 Vaccines/immunology* ; Alum Compounds/pharmacology* ; Mice, Inbred BALB C ; Vaccines, Subunit/immunology* ; Mice ; SARS-CoV-2/immunology* ; Oligodeoxyribonucleotides/administration & dosage* ; Female ; Adjuvants, Immunologic ; COVID-19/immunology* ; Antibodies, Viral/blood* ; Immunogenicity, Vaccine ; Spike Glycoprotein, Coronavirus/immunology* ; Antibodies, Neutralizing/blood* ; Adjuvants, Vaccine ; Immunoglobulin G/blood*

To screen the best genotypeⅠJapanese encephalitis virus subunit vaccine candidate antigens, the prMEIII gene, the polytope gene and the prMEIII-polytope fusion gene of the GenotypeⅠJapanese encephalitis virus GS strain were cloned into prokaryotic expression vector pET-30a. The recombinant proteins were obtained after the induction and purification. The prepared recombinant proteins were immunized to mice, and the immunogenicity of the subunit vaccine candidate antigens was evaluated through monitoring the humoral immune response by ELISA, detecting the neutralizing antibody titer by plaque reduction neutralization test, and testing the cell-mediated immune response by lymphocyte proliferation assay and cytokine profiling. The recombinant proteins with the molecular weights of 35 (prMEIII), 28 (polytope antigen) and 57 kDa (prMEIII-polytope) induced strong humoral and cellular immune responses in mice. Compared with prMEIII-polytope and polytope proteins, the prMEIII protein induced a significant expression of IL-2 and IFN-γ (P<0.05) and the significant lymphoproliferation of splenocytes (P<0.05). The neutralizing antibody titer induced by the prMEIII protein was close to that induced by the commercial attenuated vaccine SA14-14-2 (P>0.05). The study suggests that the prMEIII protein can be used for the development of the Japanese encephalitis virus subunit vaccine.
Animals ; Antibodies, Viral ; blood ; Antigens, Viral ; immunology ; Encephalitis Virus, Japanese ; immunology ; Encephalitis, Japanese ; immunology ; prevention & control ; Immunogenicity, Vaccine ; Mice ; Mice, Inbred BALB C ; Vaccines, Subunit ; immunology ; Viral Vaccines ; immunology

Recombinant Fl-V (rFl-V) fusion protein is the main ingredient of the current candidate vaccine against Yersinia pestis infection, which has been under investigation in clinical trial in USA. We investigated the soluble expression conditions of rF1-V in Escherichia coli BL21 (DE3) that we constructed before. After scale-up and optimization of fermentation processes, we got the optimized fermentation process parameters: the culture was induced at the middle exponential phase with 50 µmol/L of IPTG at 25 °C for 5 h. Soluble rFl-V protein was isolated to 99% purity by ammonium sulfate precipitation, ion exchange chromatography, hydrophobic chromatography and gel filter chromatography. The protein recovery was above 20%. Protein identity and primary structure were verified by mass spectrometry and Edman sequencing. Results of purity, quality and western blotting analysis indicated that the target protein is a consistent and properly folded product. Furthermore, the immunogenicity of various antigens formulated with aluminum hydroxide adjuvant was evaluated in mice. Serum antibody titers of 4 groups including 20 µg rFl, rV and rFl-V and 10 µg rFl+10 µg rV, were assayed by ELISA after 2 doses. The antibody titers of anti-Fl with 20 µg rFl-V were obviously higher than titers with other groups; meanwhile there were no significant difference of anti-V antibody titers among them. These findings confirm that rFl-V would be the active pharmaceutical ingredient of the plague subunit vaccine.
Adjuvants, Immunologic ; Animals ; Antibodies, Bacterial ; blood ; Antibody Formation ; Antigens, Bacterial ; immunology ; Blotting, Western ; Chromatography, Ion Exchange ; Enzyme-Linked Immunosorbent Assay ; Mice ; Plague ; prevention & control ; Plague Vaccine ; immunology ; Recombinant Fusion Proteins ; immunology ; Vaccines, Subunit ; immunology ; Yersinia pestis

Cervical cancer is the fourth most lethal women's cancer worldwide. Current treatments against cervical cancer include surgery, radiotherapy, chemotherapy, and anti-angiogenic agents. However, despite the various treatments utilized for the treatment of cervical cancer, its disease burden remains a global issue. Persistent infection of human papillomavirus (HPV) has been identified as an essential step of pathogenesis of cervical cancer and many other cancers, and nation-wide HPV screening as well as preventative HPV vaccination program have been introduced globally. However, even though the commercially available prophylactic HPV vaccines, Gardasil (Merck) and Cervarix (GlaxoSmithKline), are effective in blocking the entry of HPV into the epithelium of cervix through generation of HPV-specific neutralizing antibodies, they cannot eliminate the pre-existing HPV infection. For these reason, other immunotherapeutic options against HPV-associated diseases, including therapeutic vaccines, have been continuously explored. Therapeutic HPV vaccines enhance cell-mediated immunity targeting HPV E6 and E7 antigens by modulating primarily dendritic cells and cytotoxic T lymphocyte. Our review will cover various therapeutic vaccines in development for the treatment of HPV-associated lesions and cancers. Furthermore, we will discuss the potential of immune checkpoint inhibitors that have recently been adopted and tested for their treatment efficacy against HPV-induced cervical cancer.
Dendritic Cells/immunology ; Female ; Genetic Vectors ; Humans ; *Immunotherapy ; Papillomavirus Infections/*complications/therapy ; Papillomavirus Vaccines/therapeutic use ; *Translational Medical Research ; Uterine Cervical Neoplasms/*therapy ; Vaccines, DNA/therapeutic use ; Vaccines, Subunit/therapeutic use

The levels of Streptococcus (S.) mutans infections in saliva were evaluated and a comparison for specific antibody levels among children with different levels of S. mutans infection was made. The promising epitopic regions of antigen AgI/II (PAc) and glucosyltransferase (GTF) for potential vaccine targets related to S. mutans adherence were screened. A total of 94 children aged 3-4 years were randomly selected, including 53 caries-negative and 41 caries-positive children. The values of S. mutans and those of salivary total secretory immunoglobulin A (sIgA), anti-PAc and anti-Glucan binding domain (anti-GLU) were compared to determine the correlation among them. It was found the level of s-IgA against specific antigens did not increase with increasing severity of S. mutans infection, and the complete amino acid sequence of PAc and GTFB was analyzed using the DNAStar Protean system for developing specific anti-caries vaccines related to S. mutans adherence. A significantly positive correlation between the amount of S. mutans and children decayed, missing, and filled teeth index was observed. No significant difference was detected in specific sIgA against PAc or GLU between any two groups. No significant correlation was found between such specific sIgA and caries index. A total of 16 peptides from PAc as well as 13 peptides from GTFB were chosen for further investigation. S. mutans colonization contributed to early children caries as an important etiological factor. The level of sIgA against specific antigens did not increase with increasing severity of S. mutans infection in children. The epitopes of PAc and GTF have been screened to develop the peptide-based or protein-based anti-caries vaccines.
Antibodies, Bacterial ; biosynthesis ; Antigens, Bacterial ; chemistry ; immunology ; Bacterial Proteins ; chemistry ; immunology ; Case-Control Studies ; Child, Preschool ; Dental Caries ; immunology ; pathology ; prevention & control ; Epitopes ; chemistry ; immunology ; Female ; Glucosyltransferases ; chemistry ; immunology ; Humans ; Immunoglobulin A, Secretory ; biosynthesis ; Male ; Peptides ; chemistry ; immunology ; Saliva ; chemistry ; microbiology ; Severity of Illness Index ; Streptococcal Vaccines ; biosynthesis ; chemistry ; immunology ; Streptococcus mutans ; chemistry ; immunology ; pathogenicity ; Vaccines, Subunit ; Virulence Factors ; chemistry ; immunology

To evaluate the adjuvant effect of recombinant enterovirus 71 (EV71) subunit vaccine formulated with chitosan, rabbits were orally immunized with recombinant VP1 (rVP1) or rVP1 mixed with chitosan adjuvant. Levels of virus-specific IgG and IgA antibodies in sera, mucosal wash buffer (intestine, nasal cavity, and lung), and feces were determined by indirect enzyme-linked immunosorbent assay (ELISA). The titers of neutralizing antibodies against EV71 were determined using cytopathic effect-based neutralizing assay, and levels of cytokines (IFN-gamma and IL-4) secreted from in vitro-cultured rabbit splenic lymphocytes under antigen stimulation were also determined by ELISA. Results showed that immunization with rVP1 alone could only induce low levels of serum IgG and mucosal IgA, while rVP1 combined with chitosan adjuvant were able to induce significantly higher levels of antibodies, rVP1 can only induce neutralizing antibodies when used in combination with chitosan. Levels of IFN-gamma and IL-4 in the group immunized with rVP1 plus chitosan were significantly higher than those in the group immunized with rVP1 only or those in the control groups. Our study lays the foundation for development of oral VP1 vaccine against EV71 infection.
Adjuvants, Immunologic ; administration & dosage ; Animals ; Antibodies, Viral ; immunology ; Chitosan ; administration & dosage ; immunology ; Enterovirus A, Human ; genetics ; immunology ; Enterovirus Infections ; immunology ; prevention & control ; virology ; Female ; Humans ; Rabbits ; Vaccination ; Vaccines, Subunit ; administration & dosage ; genetics ; immunology ; Viral Proteins ; administration & dosage ; genetics ; immunology ; Viral Vaccines ; administration & dosage ; genetics ; immunology

Classical swine fever (CSF), an acute and highly contagious disease of swine, is caused by classical swine fever virus. CSF is one of the most devastating diseases to the pig industry worldwide and results in serious economic losses. Currently prophylactic vaccination is still an important strategy for the control of CSF. Live attenuated vaccines (such as C-strain) are safe and effective. However, there are significant changes in the clinical features of CSF, displaying concurrent typical and atypical CSF, and simultaneous inapparent and persistent infections. Immunization failure has been reported frequently and it is difficult to distinguish between wild-type infected and vaccinated animals (DIVA). So there is an urgent need to develop more effective and safer DIVA or marker vaccines for the control of CSF. In this review, some of the most recent advances in new-type vaccines against CSF, including DNA vaccines, live virus-vectored vaccines, protein or peptide-based vaccines, gene-deleted vaccines and chimeric pestivirus-based vaccines, are reviewed and discussed.
Animals ; Classical Swine Fever ; prevention & control ; Classical swine fever virus ; Swine ; Vaccination ; veterinary ; Vaccines, Attenuated ; immunology ; Vaccines, DNA ; immunology ; Vaccines, Subunit ; immunology ; Viral Vaccines ; immunology

Human papillomavirus (HPV)-induced cervical cancer is the second most common cancer among women worldwide. Despite the encouraging development of the preventive vaccine for HPV, a vaccine for both prevention and therapy or pre-cancerous lesions remains in high priority. Thus far, most of the HPV therapeutic vaccines are focused on HPV E6 and E7 oncogene. However these vaccines could not completely eradicate the lesions. Recently, HPV E5, which is considered as an oncogene, is getting more and more attention. In this study, we predicted the epitopes of HPV16 E5 by bioinformatics as candidate peptide, then, evaluated the efficacy and chose an effective one to do the further test. To evaluate the effect of vaccine, rTC-1 (TC-1 cells infected by rAAV-HPV16E5) served as cell tumor model and rTC-1 loading mice as an ectopic tumor model. We prepared vaccine by muscle injection. The vaccine effects were determined by evaluating the function of tumor-specific T cells by cell proliferation assay and ELISPOT, calculating the tumor volume in mice and estimating the survival time of mice. Our in vitro and in vivo studies revealed that injection of E5 peptide+CpG resulted in strong cell-mediated immunity (CMI) and protected mice from tumor growth, meanwhile, prolonged the survival time after tumor cell loading. This study provides new insights into HPV16 E5 as a possible target on the therapeutic strategies about cervical cancer.
Adult ; Aged ; Amino Acid Sequence ; Animals ; Cancer Vaccines ; administration & dosage ; immunology ; Cell Line ; Cell Line, Tumor ; Dependovirus ; genetics ; Female ; Gene Expression Regulation, Viral ; immunology ; Genetic Vectors ; genetics ; Human papillomavirus 16 ; genetics ; immunology ; Humans ; Mice ; Mice, Inbred C57BL ; Middle Aged ; Neoplasms, Experimental ; immunology ; prevention & control ; virology ; Oncogene Proteins, Viral ; genetics ; immunology ; Papillomavirus Infections ; immunology ; prevention & control ; virology ; Papillomavirus Vaccines ; administration & dosage ; immunology ; Survival Analysis ; T-Lymphocytes ; immunology ; metabolism ; Tumor Burden ; immunology ; Uterine Cervical Neoplasms ; immunology ; prevention & control ; virology ; Vaccines, Subunit ; administration & dosage ; immunology

Antigens, Bacterial ; immunology ; Drug Resistance, Bacterial ; immunology ; Signal Transduction ; immunology ; Vaccines, Subunit ; immunology

The outer membrane proteins (OMPs) of Brucella (B.) abortus have been extensively studied, but their immunogenicity and protective ability against B. abortus infection are still unclear. In the present study, B. abortus Omp28, a group 3 antigen, was amplified by PCR and cloned into a maltose fusion protein expression system. Recombinant Omp28 (rOmp28) was expressed in Escherichia coli and was then purified. Immunogenicity of rOmp28 was confirmed by Western blot analysis with Brucella-positive mouse serum. Furthermore, humoral- or cell-mediated immune responses measured by the production of IgG1 or IgG2a in rOmp28-immunized mice and the ability of rOmp28 immunization to protect against B. abortus infection were evaluated in a mouse model. In the immunogenicity analysis, the mean titers of IgG1 and IgG2a produced by rOmp28-immunized mice were 20-fold higher than those of PBS-treated mice throughout the entire experimental period. Furthermore, spleen proliferation and bacterial burden in the spleen of rOmp28-immunized mice were approximately 1.5-fold lower than those of PBS-treated mice when challenged with virulent B. abortus. These findings suggest that rOmp28 from B. abortus is a good candidate for manufacturing an effective subunit vaccine against B. abortus infection in animals.
Animals ; Antibodies, Bacterial/blood ; Blotting, Western/veterinary ; Brucella Vaccine/*immunology ; Brucella abortus/*immunology ; Brucellosis, Bovine/*immunology/microbiology/*prevention & control ; Cattle ; Cloning, Molecular ; Electrophoresis, Polyacrylamide Gel/veterinary ; Enzyme-Linked Immunosorbent Assay/veterinary ; Female ; Immunization/veterinary ; Immunoglobulin G/blood ; Immunoglobulin Isotypes/blood ; Membrane Proteins/genetics/*immunology ; Mice ; Mice, Inbred BALB C ; Models, Animal ; Recombinant Proteins/genetics/immunology ; Vaccines, Subunit/immunology