Distinct binding specificities of integrins alpha 4 beta 7 (LPAM-1), alpha 4 beta 1 (VLA-4), and alpha IEL beta 7

Int Immunol. 1994 Feb;6(2):263-75. doi: 10.1093/intimm/6.2.263.

Abstract

Integrin receptors are important for regulating lymphocyte recirculation and recruitment to sites of inflammation. Transfectants of the B cell lymphoma 38C13 were generated that differ exclusively in the expression of integrin beta 1 or beta 7 subunits allowing for a functional comparison of lymphocyte Peyer's patch HEV adhesion molecule 1 (LPAM-1) (alpha 4 beta 7) and very late antigen 4 (VLA-4) (alpha 4 beta 1) in an identical cellular environment. Whereas 38-beta 7 transfectants bound to purified and cellular mucosal addressin cell adhesion molecule (MAdCAM-1), unstimulated 38-beta 1 cells failed to bind MAdCAM-1. Treatment of 38-beta 1 cells with Mn2+ but not with PMA induced low level binding to MAdCAM-1. MAdCAM-1 adhesion of 38-beta 7 cells was constitutive and not enhanced by Mn2+ treatment. Similarly, MAdCAM-1-dependent adhesion to mucosal high endothelial venules was shown for 38-beta 7 but not for 38-beta 1 cells. The results therefore establish the LPAM-1-MAdCAM-1 interaction as the functionally dominant adhesion pathway for regulating lymphocyte homing to mucosal sites. Nonetheless, the activated VLA-4 on some lymphocytes may be involved in MAdCAM-1 recognition or promote binding to MAdCAM-1 in other tissues. By contrast, 38-beta 7 and 38-beta 1 transfectants did not differ in their binding capacity for vascular cell adhesion molecule 1 (VCAM-1) or fibronectin and LPAM-1 did not display any preference for interacting with either MAdCAM-1 or VCAM-1. LPAM-1 may therefore contribute significantly to cellular functions previously attributed to VLA-4. Interestingly, functional analysis of the intraepithelial lymphocyte integrin alpha IEL beta 7 which is structurally related to LPAM-1 did not reveal detectable binding activity for MAdCAM-1, VCAM-1, or fibronectin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Blotting, Western
  • CHO Cells
  • Cell Adhesion
  • Cell Adhesion Molecules / metabolism*
  • Cricetinae
  • Fibronectins / metabolism
  • Immunoglobulins / metabolism
  • Integrin beta Chains*
  • Integrins / metabolism*
  • Mice
  • Molecular Sequence Data
  • Mucoproteins / metabolism
  • Precipitin Tests
  • Receptors, Very Late Antigen / metabolism
  • Tumor Cells, Cultured
  • Vascular Cell Adhesion Molecule-1

Substances

  • Cell Adhesion Molecules
  • Fibronectins
  • Immunoglobulins
  • Integrin beta Chains
  • Integrins
  • Madcam1 protein, mouse
  • Mucoproteins
  • Receptors, Very Late Antigen
  • Vascular Cell Adhesion Molecule-1
  • integrin alpha4beta7
  • integrin beta7