Rabbit antisera with specificity for isolated mouse T-lymphocyte receptors.

Rabbit antibodies obtained after immunization of mouse immunoglobulin (MIg)-tolerant rabbits with B6 anti-CBA IgG and having specificity for B6 anti-CBA IgG and T-cell receptors (antiserum 5936) were used to isolate 5936-reactive molecules from B6 anti-CBA mixed lymphocyte culture supernatants. Such 5936-reactive molecules were produced by the B6 T cells, and they did not react with rabbit anti-MIg antisera. They had a mol. wt of 50,000-75,000, and were single-chain polypeptides that did not react with concanavalin A (Con A)--Sepharose. These molecules were in turn injected into rabbits, and the antisera thus obtained had the following characteristics: (1) they reacted against B6 anti-CBA T-cell receptor material but not against B6 anti-CBA IgG; (2) they reacted with about 35% of B6 (H-2b, Ig-1b) anti-CBA T cells, 25% of B6 Con A blasts and 0-10% of normal B6 T cells but not with B6 lipopolysaccharide (LPS) blasts, C3H.B10 (H-2b, Ig-1j) anti-CBA or CBA anti-B6 T cells, CBA Con A blasts or normal CBA T cells; and (3) they reacted with the same 50,000-75,000 mol. wt, T-cell-derived molecules as did antiserum 5936. The implications of these findings are discussed in relation to the nature of T-cell receptors.