RESUMO
PURPOSE: The third variable (V3) loop of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein has been intensively studied for AIDS vaccine development. Bacille Calmette-Guerin (BCG) is widely used to immunize against tuberculosis and has many advantages as a vaccine vehicle, such as low toxicity, adjuvant potential, low cost, and long-lasting immune-inducing capacity. This work was initiated to investigate the immunogenicity of recombinant BCG (rBCG-mV3) designed to express trimeric HIV-1 V3 loop (mV3) in rBCG-mV3-immunized animals. MATERIALS AND METHODS: HIV-1 V3-concatamer was cloned into pMV261, a BCG-expression vector, and then rBCG-mV3 was constructed by introducing the recombinant plasmid (pMV-V3). The recombinant BCG was examined with regard to its expression of V3-concatamer and the genetic stability in vivo and in vitro. The immune responses induced by recombinant BCG were tested in immunized mice and guinea pigs. RESULTS: The rBCG-mV3 expressed detectable amounts of V3-concatamer when induced by single heat-shock. The recombinant BCG was genetically stable and maintained the introduced mV3 gene for several weeks. V3-specific antibodies were clearly detected 6 weeks after inoculation. The antibody titer rapidly increased after immunization up to 10 weeks, and then maintained for over 4 weeks. IgG2a was prevalent in the V3-specific antiserum. The recombinant BCG was also effective in inducing delayed-type hypersensitivity responses in the immunized guinea pigs. rBCG-immunized mice retained substantial amounts of V3-specific T cells in the spleen, even 5 months after the first immunization. CONCLUSION: Recombinant BCG-mV3 is very efficient in inducing humoral and long-lasting cell-mediated immunity against HIV-1 V3 in the immunized animals.
Assuntos
Animais , Feminino , Humanos , Camundongos , Vacinas contra a AIDS/genética , Vacina BCG/genética , Cobaias , HIV-1/imunologia , Imunidade Celular/genética , Imunidade Humoral/genética , Camundongos Endogâmicos BALB C , Produtos do Gene env do Vírus da Imunodeficiência Humana/genéticaRESUMO
PURPOSE: The third variable (V3) loop of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein has been intensively studied for AIDS vaccine development. Bacille Calmette-Guerin (BCG) is widely used to immunize against tuberculosis and has many advantages as a vaccine vehicle, such as low toxicity, adjuvant potential, low cost, and long-lasting immune-inducing capacity. This work was initiated to investigate the immunogenicity of recombinant BCG (rBCG-mV3) designed to express trimeric HIV-1 V3 loop (mV3) in rBCG-mV3-immunized animals. MATERIALS AND METHODS: HIV-1 V3-concatamer was cloned into pMV261, a BCG-expression vector, and then rBCG-mV3 was constructed by introducing the recombinant plasmid (pMV-V3). The recombinant BCG was examined with regard to its expression of V3-concatamer and the genetic stability in vivo and in vitro. The immune responses induced by recombinant BCG were tested in immunized mice and guinea pigs. RESULTS: The rBCG-mV3 expressed detectable amounts of V3-concatamer when induced by single heat-shock. The recombinant BCG was genetically stable and maintained the introduced mV3 gene for several weeks. V3-specific antibodies were clearly detected 6 weeks after inoculation. The antibody titer rapidly increased after immunization up to 10 weeks, and then maintained for over 4 weeks. IgG2a was prevalent in the V3-specific antiserum. The recombinant BCG was also effective in inducing delayed-type hypersensitivity responses in the immunized guinea pigs. rBCG-immunized mice retained substantial amounts of V3-specific T cells in the spleen, even 5 months after the first immunization. CONCLUSION: Recombinant BCG-mV3 is very efficient in inducing humoral and long-lasting cell-mediated immunity against HIV-1 V3 in the immunized animals.
Assuntos
Animais , Feminino , Humanos , Camundongos , Vacinas contra a AIDS/genética , Vacina BCG/genética , Cobaias , HIV-1/imunologia , Imunidade Celular/genética , Imunidade Humoral/genética , Camundongos Endogâmicos BALB C , Produtos do Gene env do Vírus da Imunodeficiência Humana/genéticaRESUMO
BACKGROUND & OBJECTIVES: HIV-1 gp160 is an important structural protein for the virus cell interaction and virus entry. Therefore, it is regarded as the most important target for HIV-1 vaccine development. In this study we investigated the use of HIV-1 gp160-DNA construct in eliciting specific and cross reactive cell mediated immune response in mice. METHODS: DNA segment encoding env, tat and rev genes of HIV-1 subtype B (strain BRU-2) was amplified and cloned into mammalian expression vector pCI to generate plasmid pCIBRU-TRE. Mice were injected intramuscularly four times at biweekly intervals with 100 micrograms/dose of pCIBRU-TRE in normal saline, and subsequently analysed for anti HIV-envelope (env) immune responses. RESULTS: A low antibody level was detected as determined by ELISA after 4 doses. Subsequent inoculations failed to increase the antibody titres significantly. Spleen cells from the immunized mice were used for the detection of cellular immune response by lymphocyte proliferation assays (LPA), in vitro production of cytokines and cytotoxic T lymphocyte (CTL) assays. T cell response which was seen from the second week onwards, persisted even at the end of 24 wk following the last dose. Similar levels of T cell proliferation were observed on stimulation with either homologous or heterologous peptides. Cytokine studies showed a Th1 type of response. A cross clade MHC class I restricted CTL response was observed against target cells stimulated with either homologous or heterologous HIV antigens. INTERPRETATION & CONCLUSION: This study demonstrated that DNA encoding full length HIV-1 env glycoprotein gp160 induces specific as well as cross reactive cell mediated immune responses in mice. However, the induction of antibody response was poor.