Distribution of integrins on human peripheral blood mononuclear cells.
The receptors for fibronectin (FN-R) and vitronectin (VN-R) belong to a family of integral membrane glycoproteins known to be involved in cell-extracellular matrix and cell-cell interactions named integrins (FN-R = beta 1 integrin and VN-R = beta 3 integrin). Adhesion studies using FN-coated plastic dishes and highly purified subpopulations of peripheral blood mononuclear cells (PBMCs) showed a strong binding of monocytes and T lymphocytes to FN but virtually no binding of B cells to FN. Binding of monocytes and T cells to FN could be partially inhibited by a hexapeptide (GRGDSP) containing the adhesive peptide sequence Arg-Gly-Asp (RGD) as well as by an anti-FN-R antibody. The distribution of beta 1 and beta 3 integrin complexes on PBMCs was characterized by immunoprecipitation of detergent extracts of 125I-labeled cells using polyclonal antibodies against these two receptors. Two surface polypeptides corresponding to the alpha and beta chains of FN-R and VN-R were found on all three cell types. To characterize these receptors further, monoclonal antibodies (MoAbs) against the very late antigens (VLAs) 1, 3, and 5 were used for immunoprecipitation studies. Monocytes and T cells reacted with VLA 5 that was previously identified as the human FN receptor, whereas no labeling with anti-VLA 5 could be shown for B cells. When cell populations were cultured in 10% human serum for 24 hours, an increase in beta 1-integrin+ monocytes and T cells was observed. The number of beta 3-integrin+ cells remained essentially unchanged. The presence of beta 1 and beta 3 integrins on monocytes as well as on T and B lymphocytes may be of significance in the ability of these cells to interact with each other and participate in hematopoiesis and certain immune reactions.
Klingemann
H G
HG
Terry Fox Laboratory, B.C. Cancer Research Center, Vancouver, Canada.
Dedhar
S
S
D001402:B-Lymphocytes / Q000032:analysis / Q000378:metabolism / Q000502:physiology; D002448:Cell Adhesion; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D016023:Integrins; D007963:Leukocytes, Mononuclear / Q000032:analysis* / Q000378:metabolism / Q000502:physiology; D008562:Membrane Glycoproteins / Q000097:blood* / Q000302:isolation & purification; D008970:Molecular Weight; D009000:Monocytes / Q000032:analysis / Q000378:metabolism / Q000502:physiology; D010969:Plastics; D017469:Receptors, Fibronectin; D011971:Receptors, Immunologic / Q000032:analysis; D019030:Receptors, Vitronectin; D013601:T-Lymphocytes / Q000032:analysis / Q000378:metabolism / Q000502:physiology
D005353:Fibronectins; D016023:Integrins; D008562:Membrane Glycoproteins; D010969:Plastics; D017469:Receptors, Fibronectin; D011971:Receptors, Immunologic; D019030:Receptors, Vitronectin