Disulfide-linked receptors for mitogenic lectins on piglet lymphocytes

The interaction between leucoagglutinating phytohemagglutinin (L-PHA), concanavalin A (Con A), soybean agglutinin (SBA) and lentil lectin (LcH) with disulfide-linked cell surface receptors on lymphocytes from mesenteric lymph nodes of 3-day piglets (PMLN) was investigated. Surface radioiodinated PMLN lymphocytes were lysed with buffer containing Nonidet-P40. The lysates were adsorbed on lectin-agarose derivatives (or bovine serum albumin-agarose). Eluates from the lectin-agarose derivatives were analyzed by one-dimensional or two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis both under reducing and nonreducing conditions. Among the various-lectin-binding polypeptides, L-PHA recognizes a single 92-kDa disulfide-linked moiety in piglet lymphocyte lysate, comprised of polydisperse 52-kDa subunits. In addition to this apparent homodimer, SBA, Con A and LcH bind a much less prominent 82-kDa heterodimer comprised of 47-kDa and 37-kDa polypeptides; these molecules are not observed in eluates of L-PHA. Binding of the 92- and 82-kDa molecules by LcH is inhibited by methyl-alpha-D-mannoside. These results indicate that there are two lectin-binding disulfide-linked glycoproteins on lymphocytes from 3-day piglets which bind preferentially to potent mitogens. The electrophoretic properties of these molecules, under both reducing and nonreducing conditions, as well as their lectin-binding properties are very similar to those observed for antigen receptor molecules on lymphocytes from other species.