INDUCTION OF AN AUTOIMMUNE-RESPONSE AGAINST SYNGENEIC LYMPHOMA-CELLS BY IMMUNOGENIC 64-KDA PROTEIN ISOLATED FROM NORMAL BLAST CELLS OF BALBC MICE/

Immunogenic proteins with identical molecular mass (64 kDa) were purif ied from a syngeneic spontaneous T cell leukaemia line, designated LB3 , and lymphoblast extracts both derived from BALB/c mice. The 64-kDa p rotein was purified by a sequence of biochemical steps from cell extra cts containing protease inhibitors. The following steps were included in the purification pathway: Sephadex C-100 gel filtration, anion-exch ange chromatography, concanavalin A (ConA) affinity chromatography, an d preparative gel electrophoresis. The immunogenic fraction isolated i n each step was subjected to the next step along the purification path way. The immunogenicity of the separated fractions was measured by a l ymph-node proliferation assay, which is indicative of delayed-type hyp ersensitivity. The final 64-kDa isolated protein of blast cells induce d in BALB/c mice an efficient lymphnode proliferation response, which was detected in the regional lymph node after challenge with the final isolated protein of LB3 cells and vice versa. In addition to their id entical molecular mass, both proteins were eluted from an anion-exchan ge column with the same NaCl concentration (0.57 M) and both expressed affinity to the ConA-Sepharose column, suggesting that they are glyco sylated. The specificity of the immunological responses induced or eli cited with the various isolated proteins was also shown. The implicati ons of these findings are discussed.