Interchromatin granules during phytohemagglutinin stimulation of human lymphocytes. A cytochemical study.

We studied the formation of interchromatin granules (IGs) in phytohemagglutinin (PHA)-stimulated lymphocytes. The bismuth staining method was used for the visualization of IGs, and we also applied high-resolution autoradiography after incubating cells in the presence of 3H-leucine during different stages of lymphocyte activation. The disaggregation of chromatin and the enlargement of interchromatinic areas in stimulated lymphocytes were found to be accompanied by an increase in the number of IGs, and it was shown that IGs were formed during all of the investigated stages of lymphocyte stimulation.