V7, a novel leukocyte surface protein that participates in T cell activation. I. Tissue distribution and functional studies

J Immunol. 1995 May 1;154(9):4423-33.

Abstract

Among a panel of mouse mAbs generated to a human T cell clone, one mAb, V7.1, inhibited T cell activation in the mixed lymphocyte reaction and was studied further. V7.1 reacted strongly with Ag-specific T cell clones, in addition to freshly isolated monocytes and granulocytes. However, the mAb reacted weakly with freshly isolated PBLs (T cells, B cells, and NK cells), T cells stimulated with phytohemagglutinin, or Con A, and did not stain the vast majority of transformed cell lines of hemopoietic origin. Stimulation of T cells with anti-CD3, or the combination of anti-CD3 and PMA, or anti-CD3, PMA and ionomycin, markedly increased V7.1 surface staining. The mAb precipitated a single polypeptide chain of approximately 135 kDa from alloactivated T cells or monocytes, which was reduced to approximately 110 kDa after treatment with N-glycanase. The proliferative response of T cells to allogeneic monocytes or B lymphoblastoid cells was inhibited by V7.1, and inhibition was maximal when the mAb was present at the initiation of culture. V7.1 also exhibited dose-dependent inhibition of the T cell response to immobilized anti-CD3 Ab in the absence of APCs, indicating that the inhibitory effect of this Ab occurs at the T cell level. Expression of CD25 (IL-2R) on anti-CD3-activated T cells and secretion of IL-2 induced with anti-CD3 and PMA were inhibited by V7.1, whereas the Ab had no effect on T cell proliferation induced by PHA or Con A or on T cell-mediated cytotoxicity. These results indicate that V7.1 recognizes a novel leukocyte surface glycoprotein, designated V7, that is up-regulated on Ag but not lectin-activated T cells, and appears to play a role in TCR/CD3-dependent T cell activation. In an accompanying study, the gene encoding the V7 Ag is described and the molecule is shown to be a novel member of the Ig superfamily.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Antibodies, Monoclonal / immunology
  • Antigens, CD
  • CD8-Positive T-Lymphocytes / immunology*
  • Cell Line
  • Cytotoxicity Tests, Immunologic
  • Flow Cytometry
  • Humans
  • Immunoenzyme Techniques
  • Interleukin-2 / analysis
  • Lectins / pharmacology
  • Leukocytes / immunology*
  • Lymphocyte Activation / immunology*
  • Lymphocyte Culture Test, Mixed
  • Membrane Glycoproteins / biosynthesis
  • Membrane Glycoproteins / genetics*
  • Precipitin Tests

Substances

  • Antibodies, Monoclonal
  • Antigens, CD
  • CD101 antigen, human
  • Interleukin-2
  • Lectins
  • Membrane Glycoproteins