Homology of human T-cell leukaemia virus envelope gene with class I HLA gene

Human T-cell leukaemia virus (HTLV), first isolated in the United States from a patient with cutaneous T-cell lymphoma¹, is a unique ^2,3 horizontally transmitted^2,4 retrovirus which is highly associated with certain adult T-cell malignancies^5-11. Also, HTLV can be transmitted in vitro to cord blood T-lymphocytes⁸. In the accompanying paper¹² it was shown that all T cells producing HTLV, whether cultured from infected persons or infected in vitro, bind a monoclonal antibody (4D12)¹³ which recognizes an epitope shared by certain cross-reactive class I major histocompatibility antigens. This antigen may account for the extra HLA-A and -B specificities detected in HTLV-infected cells using alloantisera⁴. Because of the unusual findings of apparently inappropriate HLA antigens in HTLV infected cells, we had previously looked for rearrangement of class I-related genes in HTLV infected cells but failed to find any¹⁴. Here, using molecular clones of HTLV and human major histocompatibility antigen DNA, we have shown homology between the envelope gene region of HTLV and the region of an HLA-B locus gene which codes for the extracellular portion of a class I histocompatibility antigen.