title: Evidence for cell surface association of CD2 and LFA-1 (CD11a/CD18) on T lymphocytes.
abstract: Previous studies have reported an association of the cell surface adhesion molecule CD2 with the T cell receptor and with CD45 on mouse and human T lymphocytes. In this study the association of CD2 with cell surface molecules was investigated using cell surface biotinylation of T lymphocytes, coupled with immunoprecipitation using two CD2-specific monoclonal antibodies (mAb) (RM2-5 and 12-15) and analysis by SDS-PAGE. Although both CD2 mAb immunoprecipitated CD2 from lysates of murine lymphocytes, it was found that mAb 12-15, but not RM2-5, co-precipitated two other molecules of 95 and 180 kDa. Subsequent studies revealed that the 95- and 180-kDa molecules were associated with a subspecies of CD2 (approximately 5%) on thymocytes, the antigen-specific T cell line D10, and splenic T cells but not B cells. Two lines of evidence were obtained consistent with the 95- and 180-kDa molecules being the beta and alpha chains of LFA-1. Firstly, an analysis of 12-15 mAb immunoprecipitates on 4-12% gels under reducing and nonreducing conditions shows that the 95- and 180-kDa molecules have a molecular weight and migration pattern identical to LFA-1. Secondly, depletion of LFA-1 from lysates with LFA-1 mAb abolished the ability of CD2 mAb 12-15 to co-precipitate the 95- and 180-kDa molecules, thereby identifying these as the beta and alpha chains of mouse LFA-1, respectively. These results provide evidence for the first time for an association of LFA-1 and CD2 on mouse T lymphocytes, and suggest that the association occurs with an immunologically distinct subspecies of CD2 molecules.
authors.affiliation: Division of Cell Biology, John Curtin School of Medical Research, Australian National University, Canberra City, A. C. T.
authors.forename: J G
authors.initials: JG
authors.lastname: Altin
authors.forename: E B
authors.initials: EB
authors.lastname: Pagler
authors.forename: C R
authors.initials: CR
authors.lastname: Parish
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000737:chemistry / Q000378:metabolism*; D000954:Antigens, Surface / Q000737:chemistry / Q000378:metabolism; D001402:B-Lymphocytes / Q000648:ultrastructure; D018801:CD2 Antigens; D005260:Female; D016169:Lymphocyte Function-Associated Antigen-1 / Q000737:chemistry / Q000378:metabolism*; D046911:Macromolecular Substances; D051379:Mice; D008808:Mice, Inbred CBA; D008970:Molecular Weight; D011233:Precipitin Tests; D011971:Receptors, Immunologic / Q000737:chemistry / Q000378:metabolism*; D013601:T-Lymphocytes / Q000648:ultrastructure*
chemical_list: D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D018801:CD2 Antigens; D016169:Lymphocyte Function-Associated Antigen-1; D046911:Macromolecular Substances; D011971:Receptors, Immunologic