Relationship of human immunodeficiency virus type 1 sequence heterogeneity to stage of disease.

V3 envelope sequences were determined from amplified human immunodeficiency virus type 1 (HIV-1) sequences of uncultivated leukocytes obtained sequentially from four infected adults over the course of infection. Lower levels of sequence heterogeneity were noted in samples obtained early in HIV-1 infection, prior to CD4 depletion, than in samples obtained at later times during disease. The pattern of amino acid sequence divergence included nonrandom changes, with evidence of sequence variants arising from HIV-1 quasi-species present earlier in infection. Consensus sequences for isolates obtained early after infection from different patients demonstrated a high level of conservation with one another and a consensus sequence for macrophage-tropic HIV-1 isolates. These findings suggest that a highly restricted subset of HIV-1 quasi-species can be transmitted and can establish infection.