Ly-1 (CD5), a membrane glycoprotein of mouse T lymphocytes and a subset of B cells, is a natural ligand of the B cell surface protein Lyb-2 (CD72)

J Immunol. 1992 Mar 15;148(6):1630-4.

Abstract

CD5 is a 67-kDa glycoprotein expressed on the cell surface membrane of all T lymphocytes and on a small proportion of B lymphocytes. The physiologic role of this Ag is still unknown. Structural and functional studies of CD5 suggest that it might act as a receptor for a positive signal. CD5-specific mAb augment CD3- or mitogen-induced T cell proliferation, IL-2 secretion, and IL-2R expression and induce a rise in intracellular [Ca2+]. In this report, we describe the purification of mouse CD5 protein (mCD5) and its use as a probe to search for the ligand of CD5. We demonstrate that mCD5 specifically interacts with the mouse B cell differentiation Ag CD72/Lyb-2. Three serologically defined allelic forms of mouse CD72/Lyb-2 can all interact with mCD5. We further show that mCD5 can interact with human CD72/Lyb-2, and similarly, that human CD5 can interact with mouse CD72/Lyb-2. These studies may have major implications for the mechanisms of T-B cell communication.

Publication types

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

MeSH terms

  • Animals
  • Antigens, CD / genetics
  • Antigens, CD / isolation & purification
  • Antigens, CD / metabolism*
  • Antigens, Differentiation, B-Lymphocyte / genetics
  • Antigens, Differentiation, B-Lymphocyte / metabolism*
  • Antigens, Differentiation, T-Lymphocyte / metabolism
  • Antigens, Ly / metabolism*
  • B-Lymphocytes / cytology*
  • CD5 Antigens
  • Humans
  • Ligands
  • Membrane Glycoproteins / metabolism
  • Mice
  • Protein Binding
  • Recombinant Proteins / metabolism
  • Species Specificity
  • T-Lymphocytes / cytology*

Substances

  • Antigens, CD
  • Antigens, Differentiation, B-Lymphocyte
  • Antigens, Differentiation, T-Lymphocyte
  • Antigens, Ly
  • CD5 Antigens
  • CD72 protein, human
  • Ligands
  • Membrane Glycoproteins
  • Recombinant Proteins