Thymus-Marrow Immunocompetence III. The Requirement for Living Thymus Cells

Abstract

The enhanced immunocompetence of transferred thymus-marrow cell combinations was demonstrated using the Jerne plaque-assay method. Suspensions containing both thymus and marrow cells produced more antibody to sheep erythrocytes when transferred to irradiated syngeneic hosts and stimulated with antigen than could be accounted for by the summation of thymus- or marrow-cell activities considered singly. Living homologous thymus cells were required, since the following materials were incapable of interacting with isologous marrow cells; sonicated or irradiated (53Or) mouse thymus cells or living rat thymus cells. The thymus of the host was not necessary for demonstrating thymus-marrow immunocompetence.