A single cDNA encodes multiple Ly‐6 antigenic specificities

Abstract

To determine the relationship between the structure and function of proteins coded for by the Ly-6 gene complex, we have transfected a cDNA for a Ly-6.2 specificity into COS-7 cells. A number of monoclonal antibodies which have been shown to be capable of inducing T cell activation and which have been previously considered to recognize distinct proteins all reacted with the same transfected gene product. The approach used in these studies should be useful to further elucidate the complexities of the Ly-6 alloantigen system.

Activation of human monocytes and granulocytes by monoclonal antibodies to glycosylphosphatidelinositol‐anchored antigens

“…The fact that the CDw52 mAb used here, 097, did not induce Tcell activation in that study, may be due to insufficient cross-linking as addition of a secondary antibody was found to be necessary for monocyte activation. Anti-CD59 mAb have recently been shown to act synergistically with phorbol esters, increasing proliferative activity in peripheral blood Tcells [15]. In the same study cross-linking of CD59 with mAb and GAM-HL also caused cytoplasmic calcium fluxes and inositol phosphate turnover in Tcell lines [15].…”

“…Anti-CD59 mAb have recently been shown to act synergistically with phorbol esters, increasing proliferative activity in peripheral blood Tcells [15]. In the same study cross-linking of CD59 with mAb and GAM-HL also caused cytoplasmic calcium fluxes and inositol phosphate turnover in Tcell lines [15]. In addition, mAb to the GPI-linked antigens CD24 and CD16 have been shown to induce both cytoplasmic calcium fluxes in leukocyte subsets and activation of the oxidative burst in granulocytes [17, 18, 271. In the present study, we demontrate that mAb to GPI-linked CD14, CDw52, CD59 and Cd67 cause activation of monocytes or granulocytes similar to that observed for anti-CD24 and anti-CD16.…”

“…The hypothesis that the GPI anchor may be a structure facilitating transmembrane signaling is supported by studies showing GPI anchordependent stimulatory effects of mAb to cell surface [I 117601 antigens [5], GPI linkeage of several cellular receptors and second messenger activity of GPI breakdown products [12]. A role for GPI-linked antigens in leukocyte signal transduction has been suggested from observations that mAb against a number of GPI-linked proteins trigger lymphocyte activation or act synergistically with other stimuli [13][14][15]. Similar results have been reported for mAb against the two GPI-linked antigens, CD14 (LPS-LPSbinding protein complex receptor) and CD16 (FcyRIII), on monocytes and granulocytes, respectivelyJl6-18].…”

Binding of Urokinase-type Plasminogen Activator to Its Receptor in MCF-7 Cells Activates Extracellular Signal-regulated Kinase 1 and 2 Which Is Required for Increased Cellular Motility

“…The same investigators also showed that antibodies which bind GPIanchored proteins induce tyrosine phosphorylation of cellular proteins. Jurkat cells that are treated with a monoclonal antibody specific for the GPI-anchored protein, CD59, demonstrate not only increased intracellular [Ca 2ϩ ], but also increased interleukin-2 expression and increased proliferation (4). These studies suggest that GPI-anchored proteins may be components of multiprotein complexes which transmit signals across the plasma membrane.…”

“…GPI-anchored proteins do not contain transmembrane or intracellular domains. Nevertheless, recent studies suggest that ligand binding to many GPI-anchored proteins initiates signal transduction responses (2)(3)(4). Stefanova et al (3) isolated src family tyrosine kinases in immunoprecipitates of various GPI-anchored proteins, including CD59, CD55, CD48, CD24, CD14, Thy-1, and Ly-6.…”