title: Effects of subchronic exposure to Caramel Colour III on the immune system in mice.
abstract: Administration of Caramel Colour III is associated with lymphopenia in laboratory animals, especially if the animals are fed a vitamin B6-deficient diet. Recently, functional immunological alterations in rats exposed to Caramel Colour III have been reported. The component of Caramel Colour III that is responsible for the immunological effects has been shown to be 2-acetyl-4-tetrahydroxybutyl imidazole (THI). In the present study, female Balb/c mice fed a diet with a relatively high vitamin B6 content were exposed to 2 or 10% of a commercial Caramel Colour III preparation with a low THI content (less than 25 ppm) in the drinking water for 9 wk. Although this treatment did not induce a lymphopenia in the exposed mice, flow cytometric analysis of lymphocyte subpopulations demonstrated reductions in the CD4+ and CD8+ cell populations. In addition, the proliferative response of spleen cells to B and T cell mitogens was significantly reduced in the mice exposed to 2% Caramel Colour III. No changes were observed in natural killer cell activity or in the humoral antibody response to a viral antigen. The results indicate that Caramel Colour III that meets the specified limit of less than 25 mg THI/kg may, nevertheless, interfere with the lymphoid system in mice with an adequate vitamin B6 status.
authors.affiliation: National Food Administration, Uppsala, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Thuvander
authors.forename: A
authors.initials: A
authors.lastname: Oskarsson
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D000956:Antigens, Viral / Q000276:immunology; D002182:Candy; D002241:Carbohydrates; D004032:Diet; D005260:Female; D005505:Food Coloring Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000633:toxicity; D007093:Imidazoles / Q000008:administration & dosage / Q000633:toxicity; D007109:Immunity / Q000187:drug effects*; D007166:Immunosuppressive Agents; D007376:Interleukin-2 / Q000378:metabolism; D007694:Killer Cells, Natural / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects; D008231:Lymphopenia / Q000139:chemically induced; D051379:Mice; D008807:Mice, Inbred BALB C; D009930:Organic Chemicals; D009975:Orthomyxoviridae / Q000276:immunology; D011736:Pyridoxine / Q000008:administration & dosage
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral; D002241:Carbohydrates; D005505:Food Coloring Agents; D007093:Imidazoles; D007166:Immunosuppressive Agents; D007376:Interleukin-2; D009930:Organic Chemicals; C569050:caramel coloring; C049929:2-acetyl-4(5)-tetrahydroxybutylimidazole; D011736:Pyridoxine