QUANTITATIVE STUDIES ON PRECURSORS OF CYTOTOXIC LYMPHOCYTES .2. SPECIFICITY OF PRECURSORS RESPONSIVE TO ALLOANTIGENS AND TO CONCANAVALIN-A

Abstract

A microculture system was used to examine the specificity of cytotoxic T [thymus-derived] lymphocytes (CL) derived from single precursors. Clones derived from single precursors of CL (CLP) are apparently specific. RNC mice (H-2k) simultaneously stimulated by H-2d and H-2b antigens produce clones which are specific for H-2b or H-2d, but not for both. In the lymph node (LN) the frequency of CLP giving rise to clones specific for H-2d and H-2b is 1/480 and 1/860, respectively. Clonal specificity is also maintained when Con A [concanavalin A] is used to activate the precursors. With a nonspecific assay of CL, 2.5% of the cells in LN are stimulated by Con A to produce clones of CL. Among the CLP stimulated by Con A, 2.1% of the clones are specific for H-2d alloantigens. Of the clones produced by Con A stimulation, 18% lysed EL4 [leukemia] tumor cells, which carry H-2b; however, only a small proportion of these clones were specific for the H-2b alloantigen.