title: Topical application of a tumor promoter induces proliferation of an adherent cell population in murine spleen.
abstract: The tumor-promoting phorbol esters have proven to be potent immunomodulatory agents in vitro. It has not been possible to assess the role of phorbol ester-induced alterations of immune function in tumor promotion however, due to a lack of in vivo studies. Studies were therefore designed to assess proliferative responses of murine leukocytes after in vivo exposure to these agents. Topical application of 12-O-tetradecanoylphorbol-13-acetate (TPA) was found to cause an increase in division of murine spleen cells. The effect was dose-related up to 14 micrograms per application and generally reached a peak two days after TPA application. Cell separation experiments suggested TPA was acting on an adherent cell population distinct from splenic lymphocytes. Inflammatory reactions to TPA followed a similar time-course to that observed for spleen cell proliferation. The increased levels of proliferation observed could, therefore, be due to increased division of neutrophil and/or macrophage precursors residing in the murine spleen and appeared also to be associated with the inflammatory reaction induced by TPA.
mesh_terms: D000287:Administration, Topical; D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology; D002448:Cell Adhesion; D002469:Cell Separation; D004261:DNA Replication / Q000187:drug effects; D005260:Female; D008213:Lymphocyte Activation / Q000187:drug effects*; D008214:Lymphocytes / Q000187:drug effects / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D010704:Phorbols / Q000494:pharmacology*; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology; D013755:Tetradecanoylphorbol Acetate / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D010704:Phorbols; D013755:Tetradecanoylphorbol Acetate