The effects of interferon on the recirculation of lymphocytes in the rat.

Lymphocytes from the thoracic duct (TDL) were incubated with interferon (IFN) prior to i.v. injection into syngeneic or allogeneic recipient rats. The effect of IFN treatment on the ability of lymphocytes to migrate was studied using 'standard' TDL collected overnight at 4 degrees or an 'optimal' collection of passaged TDL which recirculate with an accelerated tempo (Smith & Ford, 1983). Interferon treatment resulted in an increase in early (30 min) localization of both standard and optimal TDL into lymph nodes. Entry of standard IFN-treated TDL was increased by 91% and 54% in cervical and mesenteric lymph nodes, respectively; increases of 50% and 22% in the same lymph nodes were recorded for optimal IFN-treated TDL. Enhanced entry of standard TDL was contrasted with a reduced ability of IFN-treated TDL to migrate out of lymph nodes; there was a reduced output into the thoracic duct and a surplus of IFN-treated lymphocytes in cervical lymph nodes despite 24 hr continuous thoracic duct drainage. Incubation with interferon did not, however, alter the ability of optimal TDL to reach the thoracic duct rapidly after injection. Allogeneic lymphocytes, which are eliminated soon after injection by an NK-like cytotoxicity, a phenomenon termed ALC, were unaffected by incubation with interferon, thus IFN-treated allogeneic lymphocytes were killed after i.v. injection as rapidly as untreated cells.