[The effect of CD8+ cells on isolation and replication of HIV-1]

Human immunodeficiency virus type 1 (HIV-1) seropositive individuals are known to have a population of CD8+T lymphocytes which can suppress the replication of the virus. Two hundred and twelve peripheral blood mononuclear cells (PBMC) samples obtained from 42 seropositive individuals were examined for HIV-1 isolation. HIV-1 recovery rate reached almost 90% by coculture of CD8+ cell-depleted PBMC with uninfected normal PBMC. These results indicated the usefulness of panning method of CD8+ cell for isolation of HIV-1 from asymptomatic carriers (AC). To investigate the suppressive effect of CD8+ cells on HIV-1 replication, we characterized HIV-1 isolates from the same blood samples obtained from five AC individuals before and after the removal of CD8+ cells. Comparative studies of paired isolates revealed significant differences in their replication kinetics in the presence of autologous or allogeneic CD8+ cells. The paired isolates from four out of 5 AC individuals revealed significant differences in their genetic structures, although their biological properties, such as replication rate of cell tropism, were almost the same between the paired isolates. One exception, that of paired isolates from one AC with clinical data of near AIDS-related complex showed a similar genetic structure and similar biological properties. Thus, we showed that many AC individuals during the early clinical stages simultaneously carried two or more replication-competent HIV-ls in vivo which have different genomic backgrounds and sensitivity to the antiviral effects of CD8+ cells.