Lymphocyte proliferation responses to gp120-depleted HZ321 virus (clade A) antigen were compared to BAL human immunodeficiency virus (HIV) virus antigen (clade B) responses, clade E HIV virus antigen responses, and purified native p24 antigen responses in 15 human immunodeficiency virus type-1 (HIV-1) seropositive subjects immunized with a whole-killed inactivated gp120-depleted HIV-1 antigen in Incomplete Freund's adjuvant (HIV-1 immunogen, Remune™). A significant increase in lymphocyte proliferation to HZ321 antigen was observed after immunization with the HIV-1 immunogen (p = 0.02). A strong association was demonstrated between the HIV-1 immunizing antigen, HZ321, and native p24 antigen responses (r = 0.80, p < 0.0001). Furthermore, a strong association in terms of proliferative responses was demonstrated between HZ321 virus (clade A) responses and BAL virus (clade B) (r = 0.95, p < 0.0001) and clade E virus antigen (r = 0.92, p < 0.0001). Proliferative responses to HIV antigens also correlated with baseline CD4 counts. Taken together, these results support the specificity of immune responses induced by Remune (HIV-1 immunogen). The development of cross-reactive immune responses between clades and to the more conserved epitopes of the virus have implications in the development of therapeutic and prophylactic HIV vaccines.
