Of 29 hematopoietic cell lines tested for susceptibility to human immunodeficiency virus (HIV)-1HTLV-IIIB infection, all CD4+ cell lines became infected. Continuous culturing of infected cell lines resulted in nine HIV-1 carrier cell lines, including, for the first time, an HIV-1 carrier megakaryoblastic cell line, MEG-01/HIV. The immunophenotypic profiles of a total of 17 HIV-1 carrier cell lines (nine newly and eight previously established cell lines) were compared with their respective parental noninfected cell lines. Except for total absence of CD4 expression, the expression of other antigens was variable among the 17 HIV-1 carrier cell lines. Persistent and consistent replication of infectious HIV-1 was detected in all of them in varying quantities. The great variability observed in both the altered marker expression, with respect to that of the noninfected parental cell lines, and in the quantities of persistently produced infectious HIV-1 was, nevertheless, specific to the individual cell lines. Furthermore, the present study demonstrates that there is no apparent correlation in the quantity of HIV-1 produced to either T cell, myelomonocytic cell, or megakaryocytic cell types. Instead, the results suggest that a particular interaction between HIV-1 and individual clonal cell lines may provide insight into the extremely complex immune dysregulation associated with the pathogenesis of acquired immune deficiency syndrome. Thus, the 17 HIV-1 carrier cell lines of diverse origin presented here provide valuable and unique models for further understanding acquired immune deficiency syndrome pathogenesis at the cellular and molecular levels.