Effect of 2,7-Bis[2-diethylamino)ethoxy]fluoren-9-one dihydrochloride (Tilorone) upon Cell-mediated Immunity in Mice¹ Free

Tilorone (2,7-bis[2-(diethylamino)ethoxy]fluoren-9-one dihydrochloride) was administered to CD-1 or C57L × A F₁ mice alone or with allogeneic leukemia L1210 cells. Tilorone given alone elicited thymus-dependent lymphocytes in the spleen causing cell-mediated immunity (CMI) comparable to that of lymphocytes exposed to 5 × 10⁴ L1210 cells. This occurred whether Tilorone was administered p.o. or i.p. When administered 24 hr after L1210 cells, an adjuvant effect of Tilorone upon CMI was not demonstrable unless glass-adherent spleen cells were removed before in vitro assay. In groups given Tilorone or L1210 alone, CMI was unchanged after removal of adherent cells. Release of lymphoycte-activating factor by the spleen was unaffected by Tilorone. It is suggested that Tilorone has a moderate direct stimulatory effect upon thymus-dependent lymphocytes but may elicit inhibitory effects mediated by adherent spleen cells (macrophages and/or sticky bursa-dependent lymphocytes) that have also been stimulated by antigen.