“In vivo” activated splenic T cells are refractory to interleukin 2 growth “in vitro”

Publisher Website
Google Scholar
Abstract
Naturally activated T lymphocytes present in normal mouse spleen were studied for direct reactivity to interleukin 2 (IL 2) and for binding of anti-IL 2 receptor (IL 2R) antibodies or radiolabeled IL 2. The majority of large-sized splenic T lymphocytes are IL 2R−; thus, at the most one third of large L3T4+ T cells and of large Lyt-2+ T lymphocytes bind (weakly) anti-IL 2R antibodies; furthermore, most IL 2R+ cells in the normal spleen are actually Lyt-2−, L3T4−. Total large splenic lymphocytes do not express more than an average of 150 high-affinity IL 2R/cell. Such cell populations, as well as large T cells enriched from them, failed to proliferate exponentially in the presence of recombinant IL 2, but did not suppress the IL 2-dependent proliferative responses of small T cells activated in the same cultures. In vivo activation of small T cells, in concanavalin A-treated irradiated syngeneic hosts, also results in refractoriness to growth in recombinant IL 2. In addition, these cells remain insensitive to ligands such as concanavalin A, phorbol myristate acetate and ionomycin, in the presence or absence of IL 2. These results question the role of IL 2 as a growth factor of in vivo activated splenic T lymphocytes, or else indicate that most of these are terminally differentiated cells.