Generation of T memory cells in one-way mixed lymphocyte culture: III. Homing and lifetime of “secondary” lymphocytes

Abstract

T lymphocytes triggered to blast transformation and to proliferation in mixed lymphocyte culture (MLC) revert to “secondary” lymphocytes in the absence of the antigen. We have quantitatively recovered the T blasts from one-way MLC by 1 g velocity sedimentation, and transferred them iv to karyotypically distinguishable T-deprived recipients, syngeneic to responder cells. The blast cells home primarily in the spleen rather than in the lymph nodes. Their progeny cells are relatively long lived and sessile cells, since they can be recovered from the recipients' spleens but not from the lymph nodes for at least 20 weeks after the transfer. The blast-derived “secondary” T lymphocytes display the following properties, strikingly dissimilar from those of nonprimed T cells: (i) They respond promptly to the original stimulator cells in secondary MLC, but only to a limited extent to other allogeneic stimulator cells carrying cross-reactive H-2 specificities; (ii) they are nonresponsive or respond only very weakly to the T mitogens concanavalin A and phytohemagglutinin; (iii) they are themselves cytotoxic to relevant allogeneic target cells in vitro; and (iv) they can be promptly and efficiently reinduced to maximal cytotoxicity by second exposure to the original stimulator cells.