Potent antiretroviral therapies that suppress HIV replication have permitted mathematical modeling of the dynamics of HIV infection and clearance by measurement of the decay of viral load in plasma. When de nova infection is blocked by antiretroviral therapy, the viral load decreases exponentially after a short initial lag time ("shoulder"). This rapid decline is followed by a slower second-phase decay. The intent of this study is to utilize four antiretroviral agents (zidovudine, lamivudine, nevirapine, indinavir) and very frequent measures of viral load to explore the drug-specific kinetics of the "shoulder". The decay of long-lived HIV-infected tissue macrophages is thought to be the major determinant of the slow second phase. Further, the study intends to use immune modulating agents with the potential to increase the turnover of infected macrophages, GM-CSF or IL-12, to accelerate the second phase of viral decay.