Continuously proliferating allospecific T cells, lifespan and antigen receptors.

Abstract

AbstractAllospecific mouse T cells derived from one‐way mixed lymphocyte cultures after 19 months in tissue culture still require allogeneic stimulation for their proliferation. If injected into normal or immunodeficient mice these cells do not form tumors. After proliferation over long time periods or after extensive expansion these T cells tend to lose their cytotoxic activity which cannot be reconstituted by addition of cells from active cultures of a different specificity. Accordingly, the specificity of the cytotoxic and proliferative response was investigated. The cytotoxic activity appears to be specific for the H‐2 SD antigens, while the proliferative response and also the activation of cytotoxicity in resting cultures is only triggered by lymphocyte activating determinants (LAD) coded either inside or outside the H‐2 region.The receptors for LAD on these allospecific T cells appear to be clonally distributed. This finding comes from the observation that old and therefore highly selected lines only react to some LAD while younger ones react to many others as well. A search for immunoglobulin on these functional and antigen‐specific thymus‐derived lymphocytes (T cells) was performed using surface radioiodination, immunoprecipitation and polyacrylamide gel electrophoresis combined with autoradiography. Using various antisera no or very little immunoglobulin molecules were found on these T cells. The small amount of immunoglobulin was attributed to a contamination of allogeneic spleen cells used to stimulate the T killer cells.