CD8+ T lymphocyte control of HIV replication in cultured CD4+ cells varies among infected individuals

Production of the human immunodeficiency virus (HIV) by cultured peripheral blood mononuclear cells (PMC) from many seropositive individuals is inhibited by the presence of CD8+ T lymphocytes. In a study of 10 subjects, high levels of virus replication could be detected in cultures of purified CD4+ cells, but not in unseparated PMC. Addition of highly purified, autologous CD8+ cells to the enriched CD4+ cells resulted in a dose-dependent inhibition of HIV growth and revealed that for some individuals, even low numbers of CD8+ cells can prevent replication of the virus. The data also indicated that culturing enriched CD4+ cells could greatly enhance detection of infectious virus in blood specimens and demonstrated that the CD4+ molecule is expressed on infected T cells isolated directly from the peripheral blood.