Evolutionary origin of the T lymphocyte receptor--I. Immunochemical investigation of immunoglobulin-like cell surface protein of carp thymocytes

B cell and immunoglobulin heterogeneity in carp (Cyprinus carpio L.); an immuno(cyto)chemical study

B cell and immunoglobulin (Ig) heterogeneity was demonstrated in carp, Cyprinus carpio L., using two monoclonal antibodies (MAbs; WC14, WCI12) produced against carp serum Ig. Immunochemical results showed that both WCI4 and WCI12 react with a protein determinant on the heavy chain of Ig (relative molecular mass approximately 70,000). Immunofluorescence microscopic and flow cytometric analyses of lymphoid cells suggest three distinct subpopulations of B cells and plasma cells: WCI4+12- cells, WCI4-12+ cells, and WCI4+12+ cells. WCI4-12+ and WCI4+12+ anti-DNP antibody-secreting cells were also demonstrated with the ELISPOT assay in pronephros and spleen cell suspensions from primary immunised carp. Affinity chromatography of carp serum and sequential immunoprecipitation of 125I-labelled peripheral blood leucocyte (PBL) membrane proteins only indicated the presence of two antigenically different Ig molecules, i.e., WCI4-12+ and WCI4+12+ molecules. WCI4+12- molecules could not be detected by affinity chromatography or immunoprecipitation. During ontogeny, a shift in percentages of WCI4+12- and WCI4-12+ cells was found in the spleen and the pronephros. In these organs, WCI4+12- cells formed the majority of B cells at 2 weeks of age, but the percentages of this cell type decreased during ontogeny. On the other hand, the percentages of WCI4-12+ cells increased during development, and these cells became the major population of B cells from 13 weeks onward. The proportion of WCI4+12+ cells remained almost constant during ontogeny. The distribution of B cell subpopulations in blood was more or less stable at all ages. The functional significance of Ig heterogeneity in fish and in particular carp is discussed.

Influence of proteolysis inhibitors and immunoadsorption technique on the composition of rabbit antigen-specific receptor preparations. Presence of Fc receptors

Addition of proteolysis inhibitors during the isolation procedure of rabbit arsanylated bovine IgG specific receptors decreased significantly the amount of low-molar-mass proteins in all receptor preparations. Rabbit ARS-BGG-specific receptor preparations isolated by immunoadsorption technique contain molecules which do not react with antigen and antibodies against immunoglobulins and have identical molar mass and chymotryptic peptide composition as those of isolated Fc receptors. It is suggested that during isolation of antigen-specific receptors from the surface of lymphoid cells, Fc receptors react with complexes composed of antigen and Ig+ receptors on the surface of immunoadsorbent and are isolated together with antigen-specific receptors.

The isolation of an antigen binding factor from cultured murine T-lymphocytes

BALB/c mice were immunized with the random sequence polypeptide [Glu60 Ala40] (GA). 125I-lymphocyte suspensions were prepared from lymph nodes, radiolabelled with 125I and cultured for 18 hours. Supernatant fluids were collected and passed over an immunoabsorbant composed of [D-Glu60 D-Ala40] (D-GA) bound to Sepharose. The non-adherent fraction was then applied to GA Sepharose and the adherent material eluted with 2 M NaSCN. The eluate was relabelled with 125I, reabsorbed to GA Sepharose and eluted. This fraction bound well to GA-Sepharose (50-80%) but not to the enantiomorphic D-GA Sepharose (5-10%). This material did not react with goat antisera directed against murine IgG, IgM or IgA. It was capable of binding to rabbit antiidiotypic sera raised against BALB/c anti-GA, but not to those antibodies raised against BALB/c anti-GAT. It also showed some reaction with rabbit antiserum to a rat T cell factor (TCF). Polyacrylamide gel electrophoresis revealed a major component with an approximate molecular weight of 63,000 which was not affected by reduction and alkylation.