DIFFERENTIATION OF T-LYMPHOCYTES .4. NET INCREASES IN LOW THETA-CELLS, MAINTENANCE OF BIOLOGICAL-ACTIVITY AND DEATH OF HIGH THETA-CELLS DURING SHORT-TERM CULTURE OF MOUSE THYMOCYTES

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  • 1 January 1978
    • journal article
    • research article
    • Vol. 46  (1-2) , 31-52
Abstract
Dissociated mouse thymocytes were cultured under optimized conditions in Marbrook vessels in order to follow some aspects of T[thymus derived]-cell differentiation. Under particular conditions it was possible to obtain a 50% net increase in the total number of the peripheral T-cell like, minor low .THETA. thymocyte subpopulation over the 1st day of culture, although this increase was lost with further incubation. The increase arose from proliferation of preexistent low .THETA. cells, and not from transformation of the major, high .THETA. population. Under all conditions the high .THETA. cells died rapidly in culture. The high .THETA. and low .THETA. thymocytes apparently represent separate streams of T-cell development. There was a striking increase in responsiveness to phytohemagglutinin and concanavalin A after culture of thymocytes under these conditions. This was ascribed, not to the development of new immunocompetent T cells, but to selective cell death in the cultures eliminating some inhibitory elements. No increase in progenitors of cytotoxic lymphocytes was obtained. The results demonstrate some potential artifacts in assessing the immunocompetence of cultured thymocytes.