Healthy carriers of a human retrovirus, adult T-cell leukemia virus (ATLV): demonstration by clonal culture of ATLV-carrying T cells from peripheral blood.

Adult T-cell leukemia virus (ATLV) or ATLV-associated antigen (ATLA)-positive cell clones were isolated from peripheral blood lymphocytes of all five anti-ATLA-seropositive healthy adults tested by a limiting-dilution culture method in the presence of T-cell growth factor (TCGF) but from none of six seronegative adults similarly tested. Although ATLA-positive cells were not always detected in mass cultures of the seropositive lymphocytes, they were found consistently in T-cell cloned cultures of those lymphocytes. Continuous cultures of the ATLA-positive clones obtained were dependent on TCGF. Five clones derived from each of the five donors were maintained for greater than 4 months and, during culture, all of them acquired the ability to grow without added TCGF. The ATLA-positive clones formed rosettes with erythrocytes and expressed Leu 1, Leu 3a, and Leu 4 antigens but not Leu 2a antigen. These results indicate that anti-ATLA-seropositive healthy individuals carry ATLV in T cells circulating in their peripheral blood.