title: Primary generation of cytolytic T lymphocytes in the absence of DNA synthesis.
abstract: The requirement for DNA synthesis during the primary differentiation of cytolytic T lymphocytes (CTL) had been investigated. CTL were induced polyclonally in vitro by stimulation of normal C57BL/6 spleen cells with concanavalin A (Con A)and their cytolytic activity was tested against 51Cr-labeled target cells in the presence of Bacto Phytohemagglutinin M. With this system, CTL activity could first be detected 48 h after exposure of spleen cells to Con A. Addition of cytosine arabinoside at concentrations sufficient to reduce DNA synthesis by 95-98% in Con A-stimulated cultures did not significantly inhibit the generation of cytolytic activity on a cell-to-cell basis. These results demonstrate that derepression of the genetic information required for the expression of CTL function can occur in the absence of detectable DNA synthesis.
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D003208:Concanavalin A / Q000494:pharmacology; D003602:Cytotoxicity, Immunologic; D004247:DNA / Q000096:biosynthesis*; D007156:Immunologic Memory; D051379:Mice; D008810:Mice, Inbred C57BL / Q000276:immunology; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D003208:Concanavalin A; D004247:DNA