Actions of β-Carotene on T-Helper Cell Functions for Antibody Production

Abstract

Abstract Actions of β-carotene isomers including all-trans-, 9-cis, and 13-cis-β-carotene and a β-carotene isomer mixture extracted from alga were examined in regard to T-helper (Th) cell function for antibody (Ab) production. β-carotene isomers did not significantly enhance in vitro Ab production by murine spleen cells, which may be partly due to the paucity of antigen (Ag)-specific Th cells. We thus replaced Th cells in spleen cell suspensions with Ag-specific Th clones in order to increase the frequency of Ag-specific Th cells. Then β-carotene isomers' effects on in vitro Ab production were reassessed. In this system, the enhancing actions of β-carotene isomers on Ab production were more evident compared to controls: (1) when cells were stimulated with suboptimal doses of Ag, and (2) when a type-2 T-helper (Th2) cell clone was used. The effects of all-trans-and 9-cis-β-carotene did not differ significantly, but the effects of 13-cis-β-carotene on Th clones was less than those exhibited by other β-carot...