title: Disparate in vivo and in vitro immunomodulatory activities of rhodamine B.
abstract: At nontoxic concentrations (1-10 microgram/ml) rhodamine B (N-[9-(2-carboxyphenyl)-6-(diethylamino)-3H-xanthen-3-ylidene]-N- ethylethanaminium chloride; D & C Red No. 19; CAS no. 81-88-9), a low-molecular-weight dye, suppressed the primary in vitro plaque-forming-cell response of BDF1 mouse spleen cells both to the thymus-dependent antigen, sheep red blood cells and to the thymus-independent antigen, E. coli 0127: B8 lipopolysaccharide. Suppression was effective when the D & C Red No. 19 was added at any time up to 48 hr of culture. Rhodamine B at concentrations from 1 to 10 microgram/ml significantly suppressed mitogen-induced proliferation of both B- and T-lymphocytes in vitro. BDF1 mice exposed to 50 and 100 ppm dye in their drinking water for 14 days prior to splenectomy gave a depressed in vitro plaque-forming-cell response to sheep red blood cells. In contrast, a significant enhancement of antibody response resulted when mice were exposed to the dye and sheep-red-blood-cell antigen was administered in vivo. Mitogen-induced B- and T-lymphocyte proliferation was also enhanced in mice exposed to the dye for 14 days.
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000818:Animals; D004396:Coloring Agents / Q000494:pharmacology*; D004247:DNA / Q000096:biosynthesis; D005260:Female; D007109:Immunity / Q000187:drug effects*; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D066298:In Vitro Techniques; D008214:Lymphocytes / Q000187:drug effects; D051379:Mice; D008815:Mice, Inbred Strains; D012235:Rhodamines / Q000494:pharmacology*; D014966:Xanthenes / Q000494:pharmacology*
chemical_list: D000276:Adjuvants, Immunologic; D004396:Coloring Agents; D007166:Immunosuppressive Agents; D012235:Rhodamines; D014966:Xanthenes; D004247:DNA; C029773:rhodamine B