Characterization of a vaccinia-derived recombinant HIV-1 gp160 candidate vaccine and its immunogenicity in chimpanzees.

The human immunodeficiency virus (HIV-1) envelope glycoprotein gp160 was produced in large-scale microcarrier cultures of Vero cells, using a system involving coinfection with two recombinant vaccinia viruses. The immunogenicity of this material was studied in conjunction with a number of different adjuvant formulations, and chimpanzees were then immunized with gp160 in conjunction with Al(OH)3, Al(OH)3 and sodium deoxycholate, and a lipid-based adjuvant. The Al(OH)3-gp160 vaccine formulation elicited very poor immune responses in two chimpanzees, and these animals were further immunized with gp160 in conjunction with a lipid-based adjuvant. Immunization with the latter formulation lead to induction of high-titer neutralizing antibodies, and, following challenge with HIV-1, one chimpanzee demonstrated no evidence of virus infection over a period of 3 years. The second chimpanzee, which had previously been infected with non-A, non-B hepatitis, and two animals immunized with gp160 with Al(OH)3 and deoxycholate were not protected against challenge.