Characterization of human B-cell lines harbouring both adult T-cell leukaemia (ATL) virus and Epstein-Barr virus derived from ATL patients.

Abstract

Human B-cell lines, designated ATLB cell lines, were spontaneously established from peripheral blood of adult T-cell leukaemia (ATL) patients. The cell lines consistently expressed ATL-associated antigen (ATLA) and Epstein-Barr virus-associated nuclear antigen (EBNA). A cloned ATLB line, designated ATLB 2, showed that both ATLA and EBNA antigens were present in the same B-cell clone. In this study, we have further characterized ATLV and EBV in the cloned ATLB 2 cell line by biochemical techniques. The ATLA antigens in these clones, initially shown by immunofluorescence, were studied by immunoprecipitation with human sera from ATL patients and the Western blotting technique using a mouse monoclonal antibody (GIN-14). We identified ATLV core polypeptides 24K and 19K in the ATLB cell extracts. Furthermore, total cellular DNA and poly(A) RNA from the ATLB cell lines were analysed for the presence of viral genomes with molecularly cloned DNA probes containing the ATLV and EBV sequence, respectively. The results showed that all ATLB 2 clones contained highly conserved ATLV proviral DNA irrespective of whether or not they expressed ATLA. They also contained several copies of EB virus DNA and DNA-DNA reassociation kinetics studies clearly showed that most of the EBV DNA sequences were present in ATLB cells. ATLV-related mRNA was detected in only ATLA-positive clones (ATLB 2-3 and 2-21) but not in a negative clone (ATLB 2-45).