Polyclonal activation of Ts cells with antiserum directed against an IGH‐1 linked candidate for a T‐cell receptor constant region marker

Abstract

An anti‐T cell serum raised in allotype congenic mice recognizes the product of a new locus coding for a heavy chain‐linked polypeptide found on a subpopulation of T cells. Anti‐Ts^d raised in BALB/cAnN mice against selected C.AL‐20 T cells reacts with a cell surface antigen in virgin animals that is found on 25% of mature thymocytes and Lyt‐bearing T cells, but not on prothymocytes, Lyt1 T cells or B cells. The antigen is restricted to strains bearing the Ig‐1^d and Ig‐1^e heavy chain allotype haplotypes, and is expressed in the F₁ animal. The antigen is unlinked in expression to the Lyt2, H‐2, or kappa light chain loci. The antigen is not detected in the hematopoietic cells in the bone marrow and appears to mark only the mature peripheral pool of T cells. As previously reported, the antiserum blocks the binding of suppressor T cells to the cross‐reactive idiotype for arsonate, while reagents specific for Fab, Fc and Ig were ineffective. It seems probable that the marker may represent a T cell constant region marker analogous to the Igh products on immunoglobulin. Antiserum against this marker induces in vivo triggering of Ts cells for a wide variety of T‐dependent antigens. All subclasses of anti‐hapten antibodies are suppressed; no affinity restrictions or clonotype specificity is observed in suppressed adult mice. Results suggest that precursor T cells regulating major serum idiotypes regulate individual idiotypes.