The humoral immune response in guinea pigs primed with recombinant vaccinia virus strains ex-pressing Transmitted/Founder virus HIV-1 membrane proteins and boosted with gp140 protein / 中华微生物学和免疫学杂志

Objective To analyze the antibody responses in guinea pigs vaccinated with recombi-nant vaccinia virus( rTT) strains expressing transmitted/founder ( T/F) HIV-1 membrane proteins in combi-nation with gp140 protein.Methods Guinea pigs were primed with rTT strains and boosted twice with gp140 protein in every four weeks.Serum samples were collected from guinea pigs before immunization and in 2, 6 and 10 weeks after the last immunization for the detection of HIV-1-specific binding antibodies, neu-tralizingantibodiesandtherelativeavidityofantibodies.Results (1)Thebindingantibodiesspecificto HIV-1 B′/C, B, AE subtypes were efficiently induced by the immunization of rTT-B, rTT-C and rTT-CON vaccinia strains in combination with gp140 protein.The antibody titers ranged from 111 430 to 1 024 000. More antibodies against HIV-1 B′/C and AE subtypes were induced in guinea pigs by the immunization of rTT-C and rTT-CON strains in combination with gp140 protein than those by using rTT-B strain prime-protein boost strategy (P<0.05).No significant differences with the titers of HIV-1 B subtype specific antibody were observed among the guinea pigs immunized with the three strategies.( 2 ) High titers of SF162 and ZM109 neutralizing antibodies were induced in guinea pigs immunized with rTT-B, rTT-C and rTT-CON vac-cinia strains in combination with gp140 protein, ranging from 83.76 to 649.30.No significant differences were found among the three groups.(3) The HIV-1 V1V2-gp70 specific antibodies associated with protec-tive immunity were induced by immunization of the three virus prime-protein boost strategies.No significant differences were observed among them.(4) Antibodies induced in guinea pigs by immunization of the three strategies showed strong affinity to membrane proteins of HIV-1 B′/C, B, AE subtype strains.No significant differences were found among the three immunization strategies.Conclusion A strong humoral immune re-sponse was induced in guinea pigs primed with recombinant vaccinia virus strains expressing T/F virus HIV-1 membrane proteins and boosted with gp140 protein.

Study of the immunogenicity and virulence of replication-competent recombinant vaccinia virus in CD4+T cell-depleted mice / 中华微生物学和免疫学杂志

Objective To investigate the effects of CD4+T cell depletion in BALB/c mice on the immunogenicity and virulence of replication-competent recombinant vaccinia virus. Methods Twelve BALB/c mice were inoculated with recombinant Tiantan vaccinia ( rTV, n=8 ) or vaccinia virus Tiantan strain ( VTT, n=4) by tail scarification after the depletion of CD4+T cells with anti-CD4 monoclonal anti-body( McAb) injected intraperitoneally for three days before virus inoculation.A control group without anti-body treatment was set up accordingly.Several parameters including the body weight, pocks on tail, viral shedding and the percentage of CD4+T cells were monitored.In the fourth week after virus infection, ovaries were collected from mice and viral loads in the tissue were titrated by plaque forming assay on chick embryo fibroblast ( CEF) cells.The specific cellular immune responses against vaccinia virus and HIV induced by inoculation of VTT and rTV respectively were detected by intracellular cytokine staining ( ICS) assay.ELISA was used to detect antibodies against vaccinia virus and HIV-1 gp120.Results All mice with or without CD4 McAb treatment showed typical poxvirus pocks on tails after inoculation of vaccinia viruses, but none of them developed secondary or satellite lesions.It took a longer time for CD4+T cell-depleted mice to heal from lesions, to regain body weights and to release viruses than the mice in control group.No vaccinia virus was detected in the ovaries of CD4+T cell-depleted mice or mice in control group.The mean absorbance( A) values for the detection of HIV-specific and vaccinia virus-specific antibodies in CD4+T cell-depleted mice with ELISA were respectively 0.119 and 0.168, which were significantly lower than those in mice of control group.The titers of neutralizing antibodies against vaccinia virus in McAb/rTV treated mice (1 ∶321) were lower than those in rTV treated mice (1 ∶1286) (P<0.05).The percentages of CD4+T cells secreting IFN-γ(0.654%) in McAb/rTV treated mice were significantly lower than those in rTV treated mice in the fourth week after immunization (P <0.0004).No significant differences with the vaccinia virus-specificCD8+ T cell responses were observed among mice with or without CD4+T cells depletion.Conclusion Thereplication and dissemination of replication-competent recombinant vaccinia virus could be effectively controlledin the mice with CD4+ T cell-depletion.The depletion of CD4+ T cells significantly reduced the humoraland CD4+ T cell responses, but had no effect on CD8+ T cell responses.

Requirement of CD4 Help for Induction of CD8 T Cell Response Specific for Virally Derived H60

CD40-CD40L-mediated help from CD4 T cells is essential to induce primary CD8 T cell responses specific to the non-inflammatory cell-based antigen H60. In this study, using H60 as a model antigen, we generated recombinant vaccinia viruses (rVVs) expressing the H60 CD8 epitope and investigated whether CD4 help was required to activate the CD8 T cell response specific to the virally expressed H60. The immune response after infection with rVVs expressing H60 was similar to that after immunization with H60 congenic splenocytes, with a peak frequency of H60-specific CD8 T cells detected in the blood on day 10 post-infection. A CD8 T cell response specific for virally derived H60 was not induced in CD4-depleted mice, but was in CD40-deficient mice. These results provide insights into the characterization of the CD8 T cell response specifically for antigens originating from cellular sources compared to viral sources.

In vivo CTL Activity Induced by Prime-boost Vaccination using Recombinant Vaccinia Virus and DNA Vaccine Expressing Epitope Specific for CD8+ T Cells

DNA vaccine approaches have been applied to generate the protective immunity against various pathogens. However, the strength of immune responses induced by DNA vaccine is weak compared with conventional vaccines. The primeboost vaccination using DNA vaccine and other viral vector has been suggested as one way to circumvent this limitation. In the present study, we used in vivo CTL activity assay to determine CD8+ T cell-mediated immunity induced by prime-boost vaccination with a DNA vaccine (gB498-505 DNA) and recombinant vaccinia virus (VVgB498-505) expressing gB498-505 epitope peptide (SSIEFARL) of herpes simplex virus type 1 (HSV-1) glycoprotein B (gB). The most potent in vivo CTL activity was induced in mice received VVgB498-505 when both gB498-505 and VVgB498-505 were used at priming step and boosted with the alternative vaccine vector expressing whole antigen protein (gBw). Priming with vaccine vector expressing gBw followed by the use of VVgB498-505 at boosting step also induced strong in vivo CTL activity. We also examined in vivo CTL activity after immunization of mice with epitope-expressing vaccine vector at both priming and boosting step. Curiously, in vivo CTL activity mediated by CD8+ T cells was strongly elicited at memory stage when animals were primed with VVgB498-505 and subsequently boosted with gB498-505 DNA. Because the use of VVgB498-505 at priming followed by boosting with gB498-505 DNA induced most optimal immunity, these results suggest that the order of vaccine type should be carefully considered when used vaccine type expressing only epitope for prime-boost vaccination.

CD8+ T Cell-mediated Immunity Induced by Heterologous Prime-boost Vaccination Based on DNA Vaccine and Recombinant Vaccinia Virus Expressing Epitope

BACKGROUND: DNA vaccination represents an anticipated approach for the control of numerous infectious diseases. Used alone, however, DNA vaccine is weak immunogen inferior to viral vectors. In recent, heterologous prime-boost vaccination leads DNA vaccines to practical reality. METHODS: We assessed prime-boost immunization strategies with a DNA vaccine (minigene, gB498-505 DNA) and recombinant vaccinia virus (vvgB498- 505) expressing epitope gB498-505 (SSIEFARL) of CD8+ T cells specific for glycoprotein B (gB) of herpes simplex virus (HSV). Animals were immunized primarily with gB498-505 epitope-expressing DNA vaccine/recombinant vaccinia virus and boosted with alternative vaccine type expressing entire Ag. RESULTS: In prime-boost protocols using vvgBw (recombinant vaccinia virus expressing entire Ag) and vvgB498-505, CD8+ T cell-mediated immunity was induced maximally at both acute and memory stages if primed with vvgBw and boosted with vvgB498-505 as evaluated by CTL activity, intracellular IFN-staining, and MHC class I tetramer staining. Similarly gB498-505 DNA prime-gBw DNA (DNA vaccine expressing entire Ag) boost immunization elicited the strongest CD8+ T cell responses in protocols based on DNA vaccine. However, the level of CD8+ T cell-mediated immunity induced with prime-boost vaccination using DNA vaccine expressing epitope or entire Ag was inferior to those based on vvgBw and vvgB498-505. Of particular interest CD8+ T cell-mediated immunity was optimally induced when vvgB498-505 was used to prime and gB DNA was used as alternative boost. Especially CD8+ T cell responses induced by such protocol was longer lasted than other protocols. CONCLUSION: These facts direct to search for the effective strategy to induce optimal CD8+ T cell-mediated immunity against cancer and viral infection.

Antitumor Responses Induced by Recombinant Vaccinia Viruses Expressingp53 Antigenic Peptide and B7 / 中国肿瘤生物治疗杂志

Objective: To explore antitumor responses induced by recombinant vaccinia viruses expressing a p53 antigenic peptide (rVV-p53M) and enhanced effect of recombinant vaccinia viruses expressing costimulatory molecule B7 (rVVB7). Methods: A 135 Cys to Tyr point mutation p53-transduced P815 mastocytoma (P815-mp53) was used as an experimental tumor and the p53 protein as the model of tumor associated antigen． rVV-p53M and rVV-B7 were used as vaccine to test their induction of CTL and antitumor immunity. Results: Immunization of BABL/c mice with rVV-p53M could elicit specific CTLs, which could specifically lyse P815-mp53 cells. Immunization of mice with rVV-p53M could survive a part of mice challenged with 1×106 P815-mp53. Treatment with rVV-p53M could significantly prolong the survival oftumor-bearing mice. Admixture at 1:1 ratio of rVV-p53 M and rVV-B7 could enhance antitumor responses induced by rVV-p53M. Conclusion: Immunization with recombinant vaceinia virus expressing antigenic peptide is a useful alternative to peptide-based vaccine. Costimulatory molecule B7 can enhance antigenic peptide to induce antitumor responses.

Antitumor Responses Induced by Recombinant Vaccinia Viruses Expressing p53 Antigenic Peptide and B7 / 中国肿瘤生物治疗杂志

Objective: To explore antitumor responses induced by recombinant vaccinia viruses expressing a p53 antigenic peptide (rVV p53 M) and enhanced effect of recombinant vaccinia viruses expressing costimulatory molecule B7 (rVV B7). Methods: A 135 Cys to Tyr point mutation p53 transduced P815 mastocytoma (P815 mp53) was used as an experimental tumor and the p53 protein as the model of tumor associated antigen. rVV p53 M and rVV B7 were used as vaccine to test their induction of CTL and antitumor immunity. Results: Immunization of BABL/c mice with rVV p53 M could elicit specific CTLs, which could specifically lyse P815 mp53 cells. Immunization of mice with rVV p53 M could survive a part of mice challenged with 1?10 6 P815 mp53. Treatment with rVV p53 M could significantly prolong the survival of tumor bearing mice. Admixture at 1∶1 ratio of rVV p53 M and rVV B7 could enhance antitumor responses induced by rVV p53 M. Conclusion: Immunization with recombinant vaccinia virus expressing antigenic peptide is a useful alternative to peptide based vaccine. Costimulatory molecule B7 can enhance antigenic peptide to induce antitumor responses.

Antitumor Responses Induced by Recombinant Vaccinia Viruses Expressing p53 and B7 / 中国肿瘤生物治疗杂志

Objective: This study was aimed to explore antitumor responses induced by recombinant vaccinia viruses expressing a point mutant p53 (rVV-p53FL) and enhancive effects of recombinant vaccinia viruses expressing costimulatory molecule B7 (rVV-B7). Methods: A 135 Cys to Tyr point mutant p53 protein was used as the model of tumor associated antigen. rVV-of3FL and rVV-B7 were used as vaccines to test their induction of CTLs and antitumor immunity. Results: Immunization BABL/c mice with rVV-p53FL could elicited specific CD8+ CTLs that could effecively lyse P815-mp53 cells, a transfectant of the murine P815 mastocytoma containing the mutant p53 gene. Treatment with rVV-p53FL could survive a part of mice challenged with 1 ? 106 P815-mp53. Treatment with rVV-p53FL could significantly prolong survival of tumor-bearing force. Admixture at 1: 1 ratio of rVV-p53FL and rVV-B7 could enhance therapeutic antitumor effects of rVV-p53FL. ~Conclusion: Mutant P53 over-expressed in tumor cells can render cells targets for specific CTLs generated by immunization with mutant p53 protein based vaccine. Costimulatory molecule H7 can enhance tumor-associated antigen inducing antitumor responses.

A study of the mechanism of the effect of a recombinant vaccinia virus expressing human cartcinoembryonic antigen on CEA positive tumor / 中国免疫学杂志

Objective:To explore antitumor mechanism of a recombinant vaccinia virus expressing human carcinomembryonic antigen(rV CEA).Methods:C57bl/6 mice were immunized three times with rV CEA.Six weeks later,the splenocytes from rV CEA immunized donors were adoptively tranfered in sublethally irradiated CEA + HePa bearing recipients,meanwhile the antiumor effect of the donor splencytes in virtro was detected.Results:Splenocytes from rV CEA immunized donors expressed strong antiumor activity in CEA positive tumorbearing recipients,whereas W VV immunized and nonimmune donor cell did not.The antiumor activity was abolished when immune T cells were depleted before splencytes transfer.Conclusion:It was demonstrated that antiumor acivity induced by rV CEA was essentially mediated by immune T cells which were activated by CEA specific immune response.Adoptive immunotherapy strategies may have implications for both the study of rV CEA and the development of potential clinical applications for tumor immunotherapy.