Lymphocytes bursting induced by heparin, dextran sulfate and other polyanions.

We found that high molecular polyanions (PAs) such as dextran sulfate and heparin burst some damaged or dead lymphocytes in lymphocyte suspension isolated from living bodies, and clarified morphologically the mechanism involved in this. PAs passed through damaged cell membranes and reached the chromatin in the nucleus. Electron micrographs suggested that they then extracted histones from the chromatin and formed complexes with them, and that freed DNA formed a gel binding with the complexes in the nucleus, and the nucleus became swollen and burst due to the gel swelling pressure. To support this conjecture, the nuclei of lymphocytes were stained with propidium iodide and exposed to light to stabilize them. The stabilized nuclei were not swollen after the addition of PAs and the lymphocytes did not burst. The lymphocyte bursting effect of PAs was attributed to their negative charges which could not destroy intact cells. At this point, PAs are different from sodium dodecyl sulfate which destroys intact cells completely.