Interaction Between Two Distinct Cell Lineages in an Immune Response

Abstract

In 1961, an immunological role for the thymus was revealed by experiments which indicated that thymectomy, at birth in mice, caused a severe depletion of lymphocytes in peripheral blood, lymph nodes, and spleen and a marked deficiency in the capacity to reject foreign skin grafts [1]. Since then numerous experiments have indicated that the thymus must perform a similar function in many species (reviewed by Miller and Osoba [2]). In spite of extensive research on the thymus in the last decade, there is much controversy regarding the fate and function of the thymus lymphocytes — the predominant cell type in thymus tissue. Recent work in our laboratory suggests that thymus lymphocytes are capable of recognizing and interacting with antigen by giving rise not to antibody-forming cells, but to a progeny of recirculating small lymphocytes through the intermediary of large pyroninophilic cells. As this work was performed using one antigenic system in mice, no generalization can yet be made with respect to other systems.