Human immunodeficiency virus (HIV)-specific immune responses are generatedwith the simultaneous vaccination of a gp120-depleted, whole-killed HIV-1 immunogen with cytosine-phosphorothioate-guanine dinucleotide immunostimulatory sequences of DNA

Objectives: We compared the effect of priming with a synthetic oligodeoxynu deotide (ODN) immunostimulatory DNA sequence followed by vaccination with h uman immunodeficiency virus type 1 (HIV-1) in incomplete Freund's adjuvant (IFA) or HIV-1 antigen alone to the simultaneous administration of immunost imulatory sequences (ISS) with HIV-1 in IFA. Methods: We examined immune function involving interferon-gamma (IFN-gamma) production, RANTES (regulated upon activation, normal T cell expressed and secreted) production, and lymphocyte proliferation, all of which appear to be augmented in HIV-1-exposed, but uninfected, individuals. Results: We demonstrate that similar levels of antigen-specific IFN-gamma w ere produced from lymph node cells of the animals immunized with HIV-1 anti gen in IFA containing the CpG ODN 1826 (ISS; mean +/- SE = 450.8 +/- 224.3 pg/mL) and the group of animals primed with the ODN before injection with t he HIV-1 in IFA (mean +/- SE = 377.7 +/- 294.8 pg/mL) or HIV-1 antigen alon e (IFN-gamma = 0 pg/mL). However, the group that received the HIV-1 in IFA plus ISS mounted a stronger lymphocyte proliferation (mean net +/- SE = 29, 180 +/- 1,932 cpm) compared to the group primed with the ODN before injecti on with HIV-1 in IFA (mean net +/- SE = 8,575 +/- 2,978 cpm). Furthermore, the group that received the HIV-1 in IFA plus ISS also mounted stronger bet a -chemokine production measured as RANTES (mean +/- SE = 1.217 +/- 267.4 p g/mL) compared to the group that received the ODN before injection with HIV -1 in IFA (mean +/- SE = 129.1 +/- 48.5 pg/mL). antibody responses from the group that received the HIV-1 in IFA plus ISS also showed a higher p24-spe cific response that was predominantly of the immunoglobulin G IgG2b isotype . Conclusion: These results suggest that the simultaneous administration of t he ISS in the HIV-1 in IFA emulsion may be a condidate for testing in non-h uman primates and in human studies as a therapeutic and preventative vaccin e.