Naturally occurring HIV-1 isolates with differences in replicative capacity are distinguished by in situ...

Replication of human immunodeficiency virus type 1 (HIV-1) isolates in peripheral blood mononuclear cells (PBMC) has been studied by in situ hybridization using the riboprobe BH10-R3 from HTLV-IIIB. Two series of isolates were tested: (a) 20 isolates from individuals with varying severity of HIV-1 infection and (b) sequential isolates from 5 subjects showing signs of clinical progression over a 45 month observation period. The results show that HIV-1 isolates with distinct replicative capacity can be distinguished by the intensity of radioactive labeling over single infected cells after in situ hybridization. Sequential isolates from patients with clinically progressive HIV-1 infection show a gradual increase in replicative capacity over time. In PBMC cultures infected with such sequential isolates, intensity of radioactive label over single infected cells increases and is strongest with isolates obtained at the time of low CD4 counts in blood. The results suggest that the restriction of virus replication that operates in the early stages of HIV-1 infection is gradually lost with progression of the disease.