CHARACTERIZATION OF A MULTIMERIC POLYPEPTIDE COMPLEX ON THE SURFACE OF THYMUS-DERIVED CELLS IN THE MEXICAN AXOLOTL

We previously raised a rabbit antiserum (L12) against a 38 kD polypept ide which is expressed on the surface of thymocytes and peripheral T c ells of an Urodele Amphibian, the Mexican axolotl (Ambystoma mexicanum ). Here we show that L12 antibodies immunoprecipitate several labelled molecules from surface iodinated axolotl spleen cells, including the 38 kD molecule, but also two polypeptides of 43 and 22 kD which are co valently linked to other elements. Another rabbit antiserum (L10) was raised against detergent-solubilized axolotl thymocyte membranes and s hown to recognize the majority of thymocytes and about half of the spl enocytes in immunofluorescence. In Western blotting, L10 antibodies re cognized a limited number of surface polypeptides in thymocyte and spl enocyte lysates, including 43, 38, and 22 kD elements. Immune complexe s formed between L10 antibodies and solubilized splenocyte membranes w ere used to immunize BALB/c mice intrasplenically in the aim of raisin g MoAbs specific for axolotl T cells. Monoclonal antibody 87.16 was sh own to stain in immunofluorescence 26.7% of thymocytes and 26.8% of sp leen cells. This MoAb recognized a 43 kD polypeptide that can covalent ly associate on the T-cell surface with several other molecules to for m a multimeric complex.