CD8 lymphocytes from asymptomatic human immunodeficiency virus (HIV) type 1-infected patients can suppress virus production from infected CD4 cells. Suppressive activity is separate and distinct from cytotoxic T lymphocyte (CTL) reactivities and is likely mediated by a soluble factor(s). The majority of HIV-1 suppression studies have been done in the context of bulk CD8 cell cultures. In this study, viral suppression was characterized by clonal populations of CD8 cells derived from HIV-1-infected patients. Most of the suppressive clones were devoid of detectable CTL reactivity against env-, gag-, pol-, and nef-expressing targets. Among the suppressive clones derived from an individual patient, a marked heterogeneity was evident with respect to phenotypic markers, cytokine production, and T cell receptor V beta expression. These results suggest that noncytolytic virus suppression is oligoclonal in nature. Clones provide tools for future studies aimed at understanding the mechanism of suppression and identifying the suppressive factor.