Springer Online Journal Archives 1860-2000
Abstract Surfaces of cultured human lymphoid cells RPMI 1788, RPMI 4098, RPMI 8866, Raji, and WI-L2 were found to contain bothβ 2-microglobulin (β 2-μ) and HL-A determinants when tested by direct complement-dependent cytotoxicity andquantitative absorption with different cytotoxic antiβ 2-μ antisera and specific HL-A alloantisera. The same antigenic specificities were found in 3M KCl extracts of these cultured cells with a sensitiveβ 2-μ radioimmunoassay and an HL-A antigen blocking assay. Daudi cells provided a contrast, since noβ 2-μ or HL-A determinants were found on their surfaces or in 3 M KCl extracts prepared from them. Results from specific antibody blocking tests suggest a close association betweenβ 2-μ and HL-A determinants on plasma membranes of cultured human lymphoid cells. A solid state immunoadsorbent containing antiβ 2-μ antibodies effectively removed all detectable HL-A antigenic activity from some 3M KCl extracts of cultured human lymphoid cells as well as from some sera. Adsorption of HL-A antigens to these immunoadsorbents was specific since it was blocked only by prior addition ofβ 2-μ. Once on the antiβ 2-μ immunoadsorbents, HL-A antigens still reacted specifically with HL-A alloantibodies in quantitative absorption experiments. HL-A antigens andβ 2-μ could be eluted from antiβ 2-μ immunoadsorbents with a variety of chaotropic reagents and detergents, but thus far potassium bromide and sodium dodecyl sulfate (SDS) appear to be the most effective. SDS-PAGE of these eluates indicated that HL-A antigens were considerably purified by adsorption to antiβ 2-μ immunoadsorbents and that two major molecular size fragments were distinguishable, i.e., ∼33,000 for HL-A and ∼ 12,000 forβ 2-μ.
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