Acquisition of a Novel T Cell Surface Protein During Intrathymic T Cell Maturation Encoded for by the Short Arm of Chromosome 11

Abstract

The role of the thymus in T lymphocyte differentiation is well established [1]. In rodents, the thymus has been shown to be the site in which the T cell self-recognition repertoire is determined [2–4]. While the cellular and molecular events that transpire during human intrathymic T cell differentiation are as yet largely unknown, it is generally agreed that T cell maturation is associated with the loss of the T6 cortical thymocyte antigen, and the acquisition of T1, T3 and HLA-A, -B and -C antigens [5–9]. However, as anti-T1, -T3 and anti-HLA monoclonal antibodies bind to subsets of cortical (immature) thymocytes, as well as to all medullary (mature) thymocytes, these reagents are not acceptable markers of the medullary population of thymocytes. Thus, in this paper we report the production of two monoclonal antibodies, A1G3 and A3D8, which bind to a molecule that in the thymus is selectively expressed only on functional thymocytes which are exclusively located in the thymic medulla. Using hamster-human hybrids, the gene(s) encoding for this antigen mapped to the short arm of chromosome 11.