In this study, we tried to get information about the fine antigen-binding ability of purified, soluble, idiotype-positive T-cell receptor molecules. Lewis anti-DA T-cell receptors were purified from normal Lewis serum by the use of anti-idiotypic immunosorbent and sodium dodecyl sulfate-polyacrylamide gel, and were coupled to cyanogen bromide-activated Sepharose 4B. In parallel, Lewis anti-DA, Lewis anti-BN, and DA anti-Lewis alloantibody immunosorbents were prepared. The major Ag-B chain (44,000 daltons) and the two polypeptide chains (34,000 and 27,000 daltons) of Ia were purified from Lewis, DA, and BN lymphocytes and absorbent on the above-mentioned immunosorbents. We found that the major Ag-B chain as well as the two Ia chains were bound to the alloantibody columns if they were derived from the corresponding allogeneic strain. No retaining ability for self-major histocompatibility complex (MHC) or third-party MHC chains was noted with the alloantibody immunosorbents. When using immunosorbents made up of idiotypic T-cell receptors, only two MHC polypeptides of the relevant allo-MHC type were retained, namely, the Ag-B and the heavy Ia chains. No detectable activity was observed when testing the same column for reactivity against third-party MHC polypeptide chains. However, the Lewis anti-DA T-cell receptors could be shown to display weak, but significant, reactivity toward one Lewis MHC polypeptide chain, that is, the heavy chain of Ia type.

Animals↗

PubMed1978

Partial characterization of cell surface idiotypes on alloantigen-activated T lymphoblasts.

T lymphoblasts of specificity Lewis anti-DA, Lewis anti-BN, BN anti-DA and L.BN anti-DA were purified on Ficoll-Paque from mixed leucocyte cultures on day 5. Blasts were radiolabelled with iodine-125 by the lactoperoxidase method and lysed by the aid of Nonidet P40. Idiotypic molecules were puried from the lysates by the use of anti-idiotypic antiserum of specificity anti-(Lewis anti-DA) and Staphylococcus aureus bearing protein-A. In this way, molecules with a molecular weight of 150,000 and 75,000 daltons could be isolated from Lewis anti-DA and L.BN anti-DA T lymphoblasts but no significant radioactivity was brought down by the same procedure from Lewis Lewis anti-BN or BN anti-DA T lymphoblasts. No additional molecules were detected on the lower molecular weight regions where light chains of Ig type as well as conventional products of the MHC genes would appear. The 150,000 dalton molecules are composed of two single polypeptide chains with a molecular weight of around 75,000 daltons. These data are in complete agreement with earlier results on antigen-binding, idiotypic receptors obtained from normal rat T lymphocytes.

Animals↗