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IL-12 enhances T-helper 1 responses to recombinant vaccinia-SIV vaccines in rhesus macaques, but does not influence the outcome of SIV(251) challenge.
Benson J; Chougnet C; Guroff M; Shearer G; Paoletti E; Tartaglia J;
November 30, 1997
Conf Adv AIDS Vaccine Dev. 1997 May 4-7;:134 (Poster 29). Unique

Interleukin 12 (IL-12) and interleukin 2 (IL-2) are both potent regulators of immune responses. Each is associated with the T-Helper 1 subset of reactive T cells. The absence or suppression of these cytokines at the initiation of an immune response to antigen(s) will result in increased T-Helper 2 activity and higher levels of antigen-specific Ab production. In studies of HIV infection in humans, as well as SIV in macaques, no correlation between neutralizing antibodies and protection from, or progression of infection has been clearly established. We determined to attempt to induce increased levels of anti-SIV cellular mediated immunity through the use of rNYVAC-SIV vaccines with or without rNYVAC-IL-12 or IL-2. Several cell mediated responses were measured, including CTL, antigen-specific T-cell proliferation, and IL-2 production, as well as neutralizing antibody activity. Based on NASBA assays for viral RNA in plasma, 12 of 12 vaccinated animals challenged by the IV route are infected, although 6 are deemed not progressing to disease. In the non-vaccinated groups of IV challenged animals, all of 12 are showing progressive disease. Of the animals challenged by the intra-rectal route, 9 of 10 control animals are progressors, while 5 of 11 vaccinated animals are protected.

*Interleukin-12/PHARMACOLOGY *SIV/IMMUNOLOGY *Th1 Cells/IMMUNOLOGY *Vaccines, Synthetic/IMMUNOLOGY *Vaccinia Virus/IMMUNOLOGY