Expression of mRNAs for pore‐forming protein and two serine esterases in murine primary and cloned effector lymphocytes

The cDNAs encoding several proteins present in the granules of cytolytic effector lymphocytes have now been cloned. These included the cytolytic pore‐forming protein (PFP) or perforin, and at least six serine esterases (SE), also called granzymes. The cDNA probes for PFP, SE‐1, and SE‐2 are used here to study the expression of these proteins in murine primary effector lymphocytes. Among the stimuli effective in inducing the expression of PFP, SE‐1, and SE‐2 were recombinant interleukin‐2, the lectin concanavalin A in the presence of phorbol esters, and allogeneic cells in mixed lymphocyte cultures. Some correlation was seen between the levels of PFP and SE mRNAs and cytotoxicity measured in a standard ⁵¹Cr release assay. We also examined a panel of 13 cloned cytotoxic T Lymphocyte (CTL) lines and found that mRNAs for PFP and SE‐2 were expressed in all CTL lines, including some that were previously considered not to produce PFP. Twelve of the 13 CTL lines also proved to possess the mRNA for SE‐1. One thymoma cell line, TIMI.4, did not express mRNA for PFP, although it expressed mRNA for SE‐1 and SE‐2.