Quantitative polymerase chain reaction analysis of cytotoxic cell proteinase gene transcripts in T cells. Pattern of expression is dependent on the nature of the stimulus.

A quantitative polymerase chain reaction assay was developed that allowed us to monitor transcript levels corresponding to individual members of the cytotoxic cell proteinase (CCP) gene family during T cell activation. Selective expression was observed and shown to depend upon the mode of T cell antigen receptor stimulation. Mitogen or allogeneic stimulation of cells resulted in the appearance of transcripts corresponding to all the genes measured, whereas alpha CD3 antibody produced a response restricted to just two family members. This differential gene activation represents a heterogeneity in cytotoxic T lymphocytes that has not been recognized previously. It may indicate that the T cell branch of the immune system can distinguish between different forms of stimulation and respond by synthesizing a specific set of effector and ancillary molecules that is most appropriate for lysis of cells bearing that type of antigen. Only CCP1 transcripts correlated with cytotoxicity for all modes of stimulation. The patterns for the others are suggestive of distinct and ancillary, rather than direct effector, roles in the lytic mechanism.