Detection and biochemical characterization of the mouse mammary tumor virus 7 superantigen (Mls-1a).
Mouse mammary tumor viruses encode superantigens that bind to class II major histocompatibility complex proteins and engage T cells that bear particular V beta s. Among these superantigens is the long known, but previously uncharacterized, Mls-1a product, encoded by Mtv-7. Using a monoclonal antibody, we detect the Mtv-7 superantigen on the surface of activated B cells, but not on T cells or resting B cells. The superantigen is synthesized as a 45 kd transmembrane glycoprotein precursor, but is proteolytically processed to yield an 18.5 kd surface protein that we suggest is the functional form of the superantigen.
Winslow
G M
GM
Howard Hughes Medical Institute, Department of Medicine, National Jewish Center for Immunology and Respiratory Medicine, Denver, Colorado 80206.
Scherer
M T
MT
Kappler
J W
JW
Marrack
P
P
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000954:Antigens, Surface / Q000276:immunology; D000956:Antigens, Viral / Q000737:chemistry*; D001402:B-Lymphocytes / Q000276:immunology*; D008213:Lymphocyte Activation; D008324:Mammary Tumor Virus, Mouse / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000276:immunology; D051379:Mice; D016747:Minor Lymphocyte Stimulatory Antigens / Q000737:chemistry* / Q000276:immunology; D011499:Protein Processing, Post-Translational; D011948:Receptors, Antigen, T-Cell / Q000502:physiology*; D013601:T-Lymphocytes / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D000956:Antigens, Viral; D008562:Membrane Glycoproteins; D016747:Minor Lymphocyte Stimulatory Antigens; D011948:Receptors, Antigen, T-Cell