Bacterial lipopolysaccharide induction of a mouse spleen factor stimulating ribonucleic acid polymerase II.

When bacterial lipopolysaccharide, a B-cell mitogen, was injected intraperitoneally into mice, the rate of deoxyribonucleic acid synthesis and the number of antibody-secreting cells in the spleen increased simultaneously, reaching a maximum in 3 days. The rate of ribonucleic acid synthesis also increased during this period, and this was found to be due to activation of alpha-amanitin-sensitive transcription in lymphoid cells of the spleen. The factors stimulating ribonucleic acid polymerase II in the spleens of normal mice and those treated with lipopolysaccharide were compared, and an additional factor besides that present in normal spleens was found in the spleen of lipopolysaccharide-treated mice.