Introduction -- the immunoglobulin-like T cell receptor problem.

Abstract

No problem in modern immunology has been more frustrating and controversial than that of the nature of the receptor for antigen on T lymphocytes. Since T cells, like antibodies and B cells, exhibit exquisite specificity for antigen, it is reasonable to propose as Ehrlich first did more than 80 years ago that the cell surface antigen receptor must be antibody (1). A good deal of experimental support was obtained for this concept in the late 60’s and early 70’s (reviewed in 2), but the hypothesis was not universally accepted because evidence from various approaches indicated that the T cell receptor, if an immunoglobulin (Ig), could not be identical to the known serum isotypes (3,4). However, a precedent for Igs associated only with the plasma membrane was set by the discovery of the IgD-like molecule of murine B cells (3,5–7) which does not occur in serum. It is not surprising that surface Ig molecules, which exist in a hydrophobic environment, differ from their serum counterparts, which exist in an aqueous miliue.