Gene transcription during in vitro activation of human B lymphocytes with Staphylococcus aureus Cowan I strain

With the use of nuclear transcription run-off assays we have determined the kinetics of transcriptional activity for the c-fos, c-myc, DR beta, DQ beta, (TfR), Blast-1, and Ig kappa genes in human tonsillar B lymphocytes of high to intermediate density after stimulation with Staphylococcus aureus Cowan I strain (SAC). Nuclei were isolated at various times after stimulation with SAC. Stimulation with SAC resulted in significant increase in the transcription of all of the genes. Maximum expression of the c-fos, transferrin receptor, DR beta, and DQ beta genes was obtained within 0.5 h after stimulation. Maximum expression of c-myc and Blast-1 was obtained within 3 h. Peak expression of Ig kappa was observed at 8 h. Transcriptional activities of all genes examined, except for the Blast-1 and Ig kappa, decreased rapidly after their respective peaks; they remained at higher levels than their base line. Inhibition of protein synthesis by cycloheximide did not significantly affect the kinetics of transcription of these genes. These data demonstrate the cascade of transcriptional activity of various genes associated with human B cell activation and indicate that the induction of their transcription is independent of de novo protein synthesis.