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Session 10 Oral Abstract Session Late Breakers I Session Time: Monday, 2 pm - 4 pm Room 6E

2:45   LB4. A Novel Adenoviral Vaccine Based on a Chimpanzee Derived Isolate as a Vaccine Carrier for HIV-1 gag J. Fitzgerald1, G.-P. Gao2, J. Wilson2, and H. C. J. Ertl*1 1Wistar Inst., Philadelphia, PA and 2Univ. of Pennsylvania, Philadelphia Background: E1-deleted human adenoviral recombinants of the serotype 5 (Adhu5) have high efficacy as vaccine carriers for different antigens including those of HIV-1 in animal models. Humans are infected by common human serotypes of adenovirus such as Adhu5 early in life and a significant percentage have high levels of neutralizing antibodies to these serotypes, which impair the efficacy of recombinant vaccines based on the homologous virus. Methods: To circumvent this problem, a novel replication-defective adenoviral vaccine carrier based on E1-deleted recombinants of the chimpanzee serotype 68 (AdC68) was developed. Results: An AdC68 construct expressing a codon-optimized truncated form of the gag of HIV-1 gene induced CD8+ T cells to gag which at the height of the immune response encompassed nearly 20% of the entire splenic CD8+ T cell population. This response could be augmented further by boosting with a heterologous vaccine carrier. The vaccine-induced immune response provided protection to challenge with a vaccinia gag recombinant virus. Induction of transgene-specific CD8+ T cells and protection against viral challenge elicited by the AdC68 vaccines was not strongly inhibited in animals pre-immune to Adhu5 virus unlike an E1-deleted Adhu5 recombinant expressing the same gene of gag.

©2002 9th Conference on Retroviruses and Opportunistic Infections