Comparison of the efficacy of early versus late viral proteins in vaccination against SIV

The immune response against early regulatory proteins of simian- and human immunodeficiency virus (SIV, HIV) has been associated with a milder course of infection. Here, we directly compared vaccination with Tat/Rev versus Pol/Gag. Challenge infection with SIVmac32H (pJ5) suggested that vaccination with Tat/Rev induced cellular immune responses that enabled cynomolgus macaques to more efficiently control SIV replication than the vaccine-induced immune responses against Pol/Gag. Vaccination with Tat/Rev resulted in reduced plasma SIV loads compared with control (P = 0.058) or Pol/Gag-vaccinated (P =. 0.089) animals, with undetectable plasma viral loads in two of the four Tat/Rev-vaccinated animals. Therefore, the results warrant further investigation of the early regulatory proteins and their potential for vaccination against HIV. (C) 2002 Published by Elsevier Science Ltd.