The interaction of interdigitating cells and lymphocytes in vitro and in vivo.

To investigate the role of the NLDC-145 antigenic determinant on interdigitating cells in T-cell dependent areas of lymphoid organs, rosettes were isolated from interdigitating cells and lymphocytes from lymph nodes. By using allotypic mixtures it was established that these rosettes represented pre-existing associations of interdigitating cells and lymphocytes. Phenotypic analysis of the lymphocytes showed that most cells in these rosettes were T cells. After antigenic stimulation, an increase of helper T cells and of B cells associated with the rosettes was found. Incubation of the rosettes with the NLDC-145 antibody did not alter the composition of the rosettes. By neonatal injection of the NLDC-145 antibody, the influence of the antigen on T-cell differentiation and antigen presenting was investigated. Although the antibody could be detected easily on interdigitating cells and thymus cortex of injected animals, no direct influence of long-term injections of the antibody from birth on antigen presentation and T-cell differentiation was found.