Cutting edge: CD43 functions as a T cell counterreceptor for the macrophage adhesion receptor sialoadhesin (Siglec-1).
Sialoadhesin (Siglec-1) is a macrophage-restricted sialic acid-binding receptor that mediates interactions with hemopoietic cells, including lymphocytes. In this study, we identify sialoadhesin counterreceptors on T lymphocytes. Several major glycoproteins (85, 130, 240 kDa) were precipitated by sialoadhesin-Fc fusion proteins from a murine T cell line (TK-1). Binding of sialoadhesin to these glycoproteins was sialic acid dependent and was abolished by mutation of a critical residue (R97A) of the sialic acid binding site in the membrane distal Ig-like domain of sialoadhesin. The 130- and 240-kDa sialoadhesin-binding glycoproteins were identified as the sialomucins CD43 and P-selectin glycoprotein ligand 1 (CD162), respectively. CD43 expressed in COS cells supported increased binding to immobilized sialoadhesin. Finally, sialoadhesin bound different glycoforms of CD43 expressed in Chinese hamster ovary cells, including unbranched (core 1) and branched (core 2) O:-linked glycans, that are normally found on CD43 in resting and activated T cells, respectively. These results identify CD43 as a T cell counterreceptor for sialoadhesin and suggest that in addition to its anti-adhesive role CD43 may promote cell-cell interactions.
Department of Cell Biology and Immunology, Institute for Immunology and Inflammation, Faculty of Medicine, Vrije University, Amsterdam, The Netherlands. t.van_den_berg.cell@med.vu.nl
T K
TK
van den Berg
D
D
Nath
H J
HJ
Ziltener
D
D
Vestweber
M
M
Fukuda
I
I
van Die
P R
PR
Crocker
D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D016466:CHO Cells; D019556:COS Cells; D015815:Cell Adhesion Molecules / Q000378:metabolism; D006224:Cricetinae; D006801:Humans; D007399:Interphase / Q000276:immunology; D051917:Leukosialin; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D011485:Protein Binding / Q000276:immunology; D011971:Receptors, Immunologic / Q000378:metabolism*; D063267:Sialic Acid Binding Ig-like Lectin 1; D012795:Sialoglycoproteins / Q000378:metabolism*; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D015703:Antigens, CD; D015815:Cell Adhesion Molecules; D051917:Leukosialin; D008562:Membrane Glycoproteins; D011971:Receptors, Immunologic; C571166:SIGLEC1 protein, human; C465014:SPN protein, human; D063267:Sialic Acid Binding Ig-like Lectin 1; D012795:Sialoglycoproteins; C571167:Siglec1 protein, mouse; C497863:Spn protein, mouse