COOPERATION BETWEEN T AND B LYMPHOCYTES FROM HUMAN TONSILS IN RESPONSE TO MITOGENS AND ANTIGENS

  • 1 January 1977
    • journal article
    • research article
    • Vol. 28  (2) , 332-340
Abstract
Purified B [bone marrow-derived] lymphocytes obtained from human tonsil cell populations by removing E [sheep erythrocyte] rosette-forming cells by density sedimentation did not proliferate at 3 days in response to PHA [phytohemagglutinin] and Con A [concanavalin A] but showed a significant 3H-labeled thymidine incorporation when the PHA response was assessed at day 6 of culture. The 6th-day response, which was completely abolished by the reduction of T[thymus-derived]-cell contamination to less than 0.1% by re-rosetting and a 2nd separation, was due in part to a direct activation by PHA of contaminating T cells and in part to a T cell-mediated B-cell response. When purified B cells were stimulated for 3 days by PHA in the presence of an equal number of autologous or homologous mitomycin-treated T lymphocytes a highly significant uptake of 3H-labeled thymidine was demonstrated. The majority of blast cells obtained at day 4 in these cultures were unable to form E rosettes and showed surface immunoglobulin by immunofluorescence stain. This response was markedly decreased by previous treatment of B cells with mitomycin C and it was abolished when B cells were killed by heating at 56.degree. C for 1 h. Purified B lymphocytes from human tonsils did not respond in vitro when cultured for 6 days in the presence of soluble antigens (PPD [purified protein derivative] and Candida). A highly significant response to the same antigens could be demonstrated when B cells were cultured in the presence of autologous mitomycin-treated T cells. These models of T-B cooperation could provide an interesting tool for studying the differentiation and antibody production in vitro of human B lymphocytes.