title: Cell-mediated immune response of macaques immunized with low doses of simian immunodeficiency virus (SIV).
abstract: Many uninfected people at high risk of HIV infection developed an HIV-specific cellular immune response despite their lack of seroconversion. Therefore, they must have been exposed to HIV without subsequent infection. It has been concluded from these data, that cell-mediated immunity (CMI) rather than humoral immunity might confer protection to HIV infection. Therefore, we tried to induce such a strong CMI in macaques by different immunization strategies. Five or seven animals were immunized with high or low doses of a whole SIV split vaccine. The lower dose of the vaccine provoked a stronger T-helper cell (TH) proliferation than the higher dose, which led to a pronounced humoral immune response. To induce a strong CMI without any specific antibody response, five macaques were inoculated with low doses of infectious SIV. None of these animals seroconverted but each animal developed a SIV-specific TH response. Interestingly, we could neither detect an SIV-specific CTL activity in the animals nor did we find typical TH1- or TH2-like cytokine profiles investigating stimulated bulk-cultures from SIV-exposed animals by RT-PCR. 24 weeks after the first low dose SIV exposure the animals were boosted by a second low dose of SIV followed by a subsequent intravenous challenge with a high dose of SIV 12 weeks later. Unexpectedly, none of the animals was found to be protected against infection and the development of AIDS-like symptoms.
authors.affiliation: Department of Virology and Immunology, German Primate Centre, Göttingen, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Dittmer
authors.forename: M
authors.initials: M
authors.lastname: Spring
authors.forename: H
authors.initials: H
authors.lastname: Petry
authors.forename: T
authors.initials: T
authors.lastname: Nisslein
authors.forename: P
authors.initials: P
authors.lastname: Rieckmann
authors.forename: W
authors.initials: W
authors.lastname: Lüke
authors.forename: C
authors.initials: C
authors.lastname: Stahl-Hennig
authors.forename: G
authors.initials: G
authors.lastname: Hunsmann
authors.forename: W
authors.initials: W
authors.lastname: Bodemer
mesh_terms: D000818:Animals; D000917:Antibody Formation; D016207:Cytokines / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D015870:Gene Expression; D015658:HIV Infections / Q000276:immunology; D006679:HIV Seropositivity / Q000276:immunology; D006801:Humans; D007111:Immunity, Cellular; D007114:Immunization / Q000379:methods*; D007115:Immunization Schedule; D008213:Lymphocyte Activation; D008253:Macaca mulatta; D016097:Simian Acquired Immunodeficiency Syndrome / Q000276:immunology* / Q000517:prevention & control; D015302:Simian Immunodeficiency Virus / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014765:Viral Vaccines
chemical_list: D016207:Cytokines; D014765:Viral Vaccines