Regulation in vitro of human natural killer (NK) cell activity.

The natural killer cell activity of PBL from epidemic polyarthritis patients was depressed early after onset of symptoms but returned to normal as the patient recovered. This study found that the in vitro culture of Ross River virus, the agent responsible for epidemic polyarthritis, with PBL resulted in enhanced rather than depressed NK cell activity. Evidence was also obtained that NK cell activity could be suppressed by suppressor-T lymphocytes generated by culture of PBL with high concentrations of Concanavalin A. This suppressive activity was not due to release of a soluble mediator(s) by the suppressor T cells.