Molecular pathogenesis of human immunodeficiency virus infection

Molecular studies of the pathogenesis of human immunodeficiency virus (HIV) infections have proceded rapidly following the molecular cloning and nucleotide sequence analysis of the HIV genome. Correlation of biochemical and functional studies of HIV-infected cells with the HIV nucleotide sequence has allowed the identification and preliminary functional characterization of many HIV proteins. These include structural proteins (gag), viral enzymes (pol), and viral regulatory proteins (tat, art). Cloned HIV DNA segments have been utilized as probes for in situ nucleic acid hybridization to study the distribution of HIV-infected cells in acquired immunodeficiency syndrome (AIDS) and AIDS-related complex (ARC) patients. These studies have demonstrated the infection of macrophages as an important component of HIV-induced neurologic disease. Only very low numbers of HIV-infected lymphocytes can be identified in the peripheral blood of infected individuals. Thus, the mechanism of CD4 cell depletion in the pathogenesis of AIDS remain obscure.