Detection of HLA-D-region-associated antigens on the surface of adult T-cell leukemia virus particles by immunoelectron microscopy.

To search for lymphocyte marker antigens on the surface of human T-cell leukemia virus (HTLV), an immunoelectron microscopic study was performed on a HTLV-producing human T-cell line, MT-2, using monoclonal antibodies, such as anti-Leu-1, -Leu-2b, -Leu-3a, -Leu-5, -Leu-10 and -HLA-DR and OKIal. The reactivity of each antibody with MT-2 cells was tested by the immunoperoxidase method at the light microscopic level. OKIal, anti-HLA-DR and -Leu-10 gave positive results. At the ultrastructural level, the surface of HTLV as well as the plasma membranes of MT-2 cells were labeled with ferritin by the monoclonal antibodies OKIal, anti-HLA-DR and -Leu-10, but not by anti-Leu-1 and -Leu-3a. These findings suggest that HLA-D region -associated antigens are common antigenic determinants shared by the surface of HTLV and the plasma membranes of MT-2 cells. These antigens on the virus surface are probably picked up selectively from the plasma membranes and may play an important role in the interaction of HTLV and target T-cells.