Evidence that murine hematopoietic cell subset marker J11d is attached to a glycosyl‐phosphatidylinositol membrane anchor

摘要

AbstractGlycosyl‐phosphatidylinositol (G‐PI) has been shown to serve as membrane anchor for cell surface molecules such as Thy‐1, Ly‐6‐controlled ThB and Qa antigens. Here, we present several lines of evidence indicating that the hematopoietic cell lineage (i.e.thymocytes, B cell subset and red blood cells) marker defined by the rat monoclonal antibody J11d is also a G‐PI‐linked structure. First, surface expression of the J11d‐defined molecules, and that of the related antigen B2A2, was found to be specifically reduced by treatment of thymocytes and B lymphoma or hybridoma cells with excess ofStaphylococcus aureusPI‐specific phospholipase C; this enzyme also solubilizes a 35–40‐kDa material from erythrocyte microsomal membranes corresponding to the predominant J11d‐reactive red cell surface molecules. Second, Thy‐1−mutants of the BW5147, T1M1, S1A or S49 murine T lymphoma cells of the complementary classes A, B, C and E (i.e.shown to be defective in the enzymatic machinery that posttranslationally modify Thy‐1 molecules) also lack J11d, or express it at a very low level. Although directed at a G‐PI‐linked structure, the J11d monoclonal antibody, unlike other reagents to Thy‐1 or Ly‐6‐controlled antigens, failed to induce thymocyte proliferation even in the presence of phorbol myristate aceta