We investigated genes involved in the interleukin-2 activation of cultured lymphocytes using a differential display reverse transcription PCR technique. Three cDNA fragments corresponding to mRNAs differentially amplified in the activated lymphocytes were sequenced and identified. These fragments were identical to the 3' region of the mRNAs encoding for the tumor rejection antigen TRA 1 that is the human homologue of the murine heat shock protein gp96, the DAP12 protein that possesses an immunoreceptor tyrosine-based activation motif, and the human motor protein p87/89 expressed in the heart. These proteins are involved, respectively, in cellular communication, in signal transduction, and in cellular movements. Our findings suggest that the activation of cellular immune response by interleukin-2 is a process analogous to other known phenomena of activation of catabolic reactions of energy transduction for activities which allow adaptation of cells to stress conditions.