PRODUCTION AND CHARACTERIZATION OF MONOCLONAL-ANTIBODIES RECOGNIZING THE ALPHA-CHAIN SUBUNITS OF HUMAN IA ALLOANTIGENS

  • 1 January 1983
    • journal article
    • research article
    • Vol. 50  (4) , 613-624
Abstract
Two monoclonal antibodies, TAL-1B5 and TAL-3C3, specific for human Ia .alpha.-chain subunits were produced by fusing P3/NSI/1-Ag4-1 mouse myeloma cells with spleen cells from a BALB/c mouse immunized with purified .alpha.-chains. Specificity for the .alpha.-chain subunits was initially established using a solid-phase radioimmunoassay. Indirect binding assays demonstrated that TAL-1B5 bound strongly to all human B lymphoblastoid lines tested and to CLL [chronic lymphatic leukemia], but only weakly to PBL[peripheral blood lymphocyte]-B cells and not to PBL-T cells or the T cell lines Molt 4 and HSB-2. TAL-3C3 bound only weakly to B lymphoblastoid lines and not to CLL or PBL-B cells. From 125I cell surface-labeled lysates TAL-1B5 immunoprecipitated a 33,000(.alpha.):28,000(.beta.) Ia dimer, but TAL-3C3 failed to immunoprecipitate cell surface molecules. Under denaturing conditions both TAL-1B5 and TAL-3C3 immunoprecipitated the 33,000 .alpha.-chain subunit. Competitive inhibition studies demonstrated that both monoclonal antibodies recognize the same or spatially related .alpha.-chain antigenic determinants with some slight cross-reactivity against .beta.-chains. 2D-NEPHGE SDS-PAGE [2-dimensional-nonequilibrium pH gradient electrophoresis, sodium dodecyl sulfate polyacrylamide gel electrophoresis] analysis of TAL-1B5 immunoprecipitates from [35S]-methionine biosynthetically labeled cells revealed the presence of a number of .alpha.-chain spots in association with .beta.-chain products of 3 previously described loci (.beta.-1, .beta.-2, .beta.-3) suggesting that this antibody recognizes an antigenic site common to those human Ia .alpha.-chains so far identified.