title: Studies of immunomodulating actions of carotenoids. I. Effects of beta-carotene and astaxanthin on murine lymphocyte functions and cell surface marker expression in in vitro culture system.
abstract: The immunomodulating effects of carotenoids (beta-carotene and astaxanthin) on mouse lymphocytes were studied in in vitro culture system by use of assay for mitogen responses of spleen cells, thymocyte proliferation, interleukin 2 production, and antibody (Ab) production in vitro in response to sheep red blood cells. Changes of cell surface markers on spleen lymphocytes including Ia antigen (Ag), surface immunoglobulin, B220, and Thy-1 Ag were also examined. At a concentration of 10(-8) M, carotenoids did not show any significant effect on mitogen responses (phytohemagglutinin P and concanavalin A) on murine spleen cells, irrespective of the concentrations of mitogens used. Interleukin 2 production by murine spleen cells was not significantly altered by carotenoids in the culture media (10(-7) to 10(-9) M). [3H]thymidine incorporation by B6 thymocytes was somewhat enhanced in the presence of astaxanthin or beta-carotene when cultured in the concentration of 10(6)/ml. At higher concentrations of cells (5 x 10(6)/ml), such an effect was not observed. In assays of in vitro Ab production in response to sheep red blood cells, B6 spleen cells produced significantly more Ab-forming cells (plaque-forming cells, immunoglobulins M and G) in the presence of astaxanthin (greater than 10(-8) M) but not beta-carotene. Expression of Ia Ag seemed to be moderately enhanced on both Thy-1+ and Thy-1- spleen cells in the presence of astaxanthin (greater than 10(-9) M) but not beta-carotene. The expression of Thy-1 and surface immunoglobulin seemed unchanged with the treatment of these carotenoids. These results indicate that immunomodulating actions of carotenoids are not necessarily related to provitamin A activity, because astaxanthin, which does not have provitamin A activity, showed more significant effects in these bioassays and also indicate that such actions of carotenoid demonstrated in this study may be difficult to explain only by its oxygen-quenching capacity.
authors.affiliation: Department of Pediatrics, University of South Florida/All Children's Hospital, St. Petersburg 33701.
authors.forename: H
authors.initials: H
authors.lastname: Jyonouchi
authors.forename: R J
authors.initials: RJ
authors.lastname: Hill
authors.forename: Y
authors.initials: Y
authors.lastname: Tomita
authors.forename: R A
authors.initials: RA
authors.lastname: Good
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D000917:Antibody Formation / Q000502:physiology; D000954:Antigens, Surface / Q000032:analysis*; D002338:Carotenoids / Q000494:pharmacology*; D002455:Cell Division / Q000502:physiology; D002478:Cells, Cultured; D004912:Erythrocytes / Q000502:physiology; D005260:Female; D007376:Interleukin-2 / Q000096:biosynthesis; D008214:Lymphocytes / Q000187:drug effects* / Q000276:immunology; D051379:Mice; D008815:Mice, Inbred Strains; D008934:Mitogens / Q000494:pharmacology; D013950:Thymus Gland / Q000166:cytology; D024341:Xanthophylls; D019207:beta Carotene
chemical_list: D000276:Adjuvants, Immunologic; D000954:Antigens, Surface; D007376:Interleukin-2; D008934:Mitogens; D024341:Xanthophylls; D019207:beta Carotene; D002338:Carotenoids; C005948:astaxanthine