concanavalin-a and Vaccinia

CD43 is a cell-surface sialoglycoprotein expressed by a variety of haematopoietically derived cells, including T lymphocytes. Earlier observations of defective CD43 expression by T lymphocytes from boys with the X-chromosome-linked Wiskott-Aldrich syndrome suggested the importance of CD43 in lymphocyte function. Subsequent studies have suggested that CD43 facilitates leukocyte adhesion and has a co-stimulatory role during T-cell activation. To define the physiologically relevant function(s) of CD43, we have generated CD43-knockout mice. We report here that CD43-deficient T cells from such mice show a marked increase in their in vitro proliferative response to concanavalin A, anti-CD3, the superantigen SEB and allostimulation. Additionally, CD43-deficient T cells show a substantial enhancement in homotypic adhesion and in their ability to bind different ligands, including fibronectin and the intercellular adhesion molecule ICAM-1. Vaccinia-virus-infected CD43-knockout mice mounted an augmented anti-vaccinia cytotoxic T-cell response compared with their wild-type littermates, yet developed an increased virus load. We conclude that CD43 negatively regulates T-cell activation and adhesion and is important for viral clearance.

Topics: Animals; Antigens, CD; Cell Adhesion; Cell Line; Concanavalin A; Fibronectins; Hematopoiesis; Intercellular Adhesion Molecule-1; Leukosialin; Ligands; Lymphocyte Activation; Mice; Mice, Knockout; Nociceptin; Opioid Peptides; Sialoglycoproteins; Superantigens; T-Lymphocytes; T-Lymphocytes, Cytotoxic; Vaccinia