TY - JOUR
T1 - The human lymphocyte function-associated (HLFA) antigen and a related macrophage differentiation antigen (HMac-1)
T2 - Functional effects of subunit-specific monoclonal antibodies
AU - Hildreth, J. E.K.
AU - August, J. T.
N1 - Copyright:
Copyright 2004 Elsevier B.V., All rights reserved.
PY - 1985
Y1 - 1985
N2 - The structural and functional relations between the α- and β-subunits of the human lymphocyte function-associated antigen (HLFA) and the human Mac-1 antigen (HMac-1) have been analyzed with the use of five monoclonal antibodies that react with these proteins. The specificities of these antibodies were examined by immunoprecipitation of proteins from 125I-labeled cells and purified HLFA and HMac01 antigens. Three antibodies reacted with the Mr 95,000 common β-subunit of the proteins, and also co-precipitation the Mr 175,000 HLFA α-subunit, the Mr 165,000 HMac-1 α-subunit, and a third polypeptide α-subunit of Mr 150,000. The other antibodies were specific to noncross-reactive epitopes present on the α-subunit of HLFA or HMac-1. These specificities were confirmed in sequential immunoprecipitation studies. Peptide mapping showed that the β-subunits of HLFA and HMac-1 were identical, whereas the two α-subunits differed considerably. The HLFA α-subunit-specific monoclonal antibody inhibited phytohemagglutinin stimulation, the mixed lymphocytes reaction, cytolytic T lymphocyte-mediated killing, and tetanus toxoid stimulation, but did not affect natural killer cell-mediated killing or complement receptor type 3 function. The HMac-1 α-subunit-specific monoclonal antibody inhibited complement receptor type 3 function but had no effect on T cell or natural killer cell functions. Three monoclonal antibodies to the β-subunit inhibited all functions tested, including T cell, natural killer cell, and complement receptor type 3 activities. The results suggested that the functions of the HLFA and HMac-1 molecules may be determined by the α-subunit, and the common β-subunit also bears functionally important epitopes.
AB - The structural and functional relations between the α- and β-subunits of the human lymphocyte function-associated antigen (HLFA) and the human Mac-1 antigen (HMac-1) have been analyzed with the use of five monoclonal antibodies that react with these proteins. The specificities of these antibodies were examined by immunoprecipitation of proteins from 125I-labeled cells and purified HLFA and HMac01 antigens. Three antibodies reacted with the Mr 95,000 common β-subunit of the proteins, and also co-precipitation the Mr 175,000 HLFA α-subunit, the Mr 165,000 HMac-1 α-subunit, and a third polypeptide α-subunit of Mr 150,000. The other antibodies were specific to noncross-reactive epitopes present on the α-subunit of HLFA or HMac-1. These specificities were confirmed in sequential immunoprecipitation studies. Peptide mapping showed that the β-subunits of HLFA and HMac-1 were identical, whereas the two α-subunits differed considerably. The HLFA α-subunit-specific monoclonal antibody inhibited phytohemagglutinin stimulation, the mixed lymphocytes reaction, cytolytic T lymphocyte-mediated killing, and tetanus toxoid stimulation, but did not affect natural killer cell-mediated killing or complement receptor type 3 function. The HMac-1 α-subunit-specific monoclonal antibody inhibited complement receptor type 3 function but had no effect on T cell or natural killer cell functions. Three monoclonal antibodies to the β-subunit inhibited all functions tested, including T cell, natural killer cell, and complement receptor type 3 activities. The results suggested that the functions of the HLFA and HMac-1 molecules may be determined by the α-subunit, and the common β-subunit also bears functionally important epitopes.
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M3 - Article
C2 - 2580022
AN - SCOPUS:0022387696
SN - 0022-1767
VL - 134
SP - 3272
EP - 3280
JO - Journal of Immunology
JF - Journal of Immunology
IS - 5
ER -