The effects of urine on the viability and activity of lymphocytes.

Circulating lymphocytes were incubated for 72 hours in either pure culture medium or a medium-urine mixture in the presence of phytohemagglutinin, concanavalin A or pokeweed mitogen, and assayed for blastogenesis and viability. The amount and osmolality of the urine were varied. Between 80 and 90 per cent of the cells remained viable during the entire study despite the culture mixture. If 50 percent of the culture was replaced by urine at an osmolality of 150, 300 or 500 mOsm, a severe but uniform depression of lymphocyte activity was seen. However, if only 25 percent or less of the medium was replaced by urine at 300 mOsm, the cells stimulated as well as they did in pure medium.