Granzyme B-gene expression: a marker of human lymphocytes "activated" in vitro or in renal allografts

Human killer cells contain cytoplasmic granules in which serine esterases, or granzymes, and perforin have been identified. We have studied the induction of granzyme B-gene expression in peripheral blood lymphocytes and large granular lymphocytes activated by various stimuli in vitro as well as in cellular infiltrates at the site of renal allografts in patients with and without rejection. Using in situ hybridization, kinetic experiments have shown that granzyme B mRNA is an early marker of in vitro cell activation. Data obtained in vivo also indicate the presence of granzyme B mRNA-bearing cells, which argues in favor of the induction of granzyme B gene in cells activated in vivo.