Proliferative kinetics, phenotype and cytotoxic function of thymic and peripheral T-cell colonies

Cells produced in murine T-cell colonies grown in methylcellulose have been studied to evaluate their proliferation, phenotypic differentiation, and ability to give rise to cytotoxic cells. Colony-forming cells from presumably cortical or medullary thymocytes, separated by peanut agglutination, or from lymph nodes, showed rapid proliferation regardless of their origin, although cortical thymic colony cells showed significantly slower proliferation from day 10 to day 12 of culture. Essentially all the colony cells maintained the Lyt-1+2+ phenotype of the colony-forming cells, and no L3T4+ cells were found. The colony cells were characterized as rather mature cells by being strongly H-2-positive, and, except for a few cells, by lacking the TL antigen. Colony cells maintained the Lyt-1+2+ phenotype after expansion in liquid culture, and both cortically and medullary derived colony cells showed lectin-dependent cytotoxic activity against P-815 tumour cells. We conclude that our assay for growing thymus-derived T-cell colonies results in the proliferation of a phenotypically and functionally relatively mature cytotoxic T-lymphocyte progeny.