BETA-CAROTENE SUPPLEMENTATION ENHANCES LYMPHOCYTE-PROLIFERATION WITH MITOGENS IN HUMAN PERIPHERAL-BLOOD LYMPHOCYTES

This study was performed to determine the effect of beta-carotene supp lementation on the proliferation of human peripheral blood lymphocytes (PBL) with T-cell mitogens such as phytohemagglutinin (PHA) and conca navalin A (Con A). Subjects were healthy male university students (19 to 22 years old) without smoking habit. After the subjects were divide d into two groups; control (n=7) and beta-carotene supplemented (n=8) groups, they received lactose (30 mg/day) and beta-carotene (30 mg/day ) for 30 days, respectively. Their peripheral blood lymphocytes (PBL) were separated by Percoll-density gradient centrifugation and used for immunological assays. The number of PBL from beta-carotene supplement ed group was not significantly different from control group. Although there was also no significant difference in natural killer cell (NK) a ctivity between both groups (Control; 33.4 +/- 8.2%, beta-carotene; 32 .5 +/- 7.7%), proliferation of PBL with PHA or ConA was 1.4 to 1.9 fol d higher in beta-carotene supplemented group compared to that of contr ol group. However, the proportions of T cell subsets in PBL and interl eukin 2 (IL2) activity in the supernatant of PBL cultures stimulated i n vitro with Con A were not significant differences between control an d beta-carotene supplemented groups. In particular, IL2 activity was l ower in beta-carotene supplemented subjects compared to that of contro l subjects. These results suggest that the enhancement of PBL prolifer ation following beta-carotene supplementation is not due to the qualit ative change in T cell subsets of PBL and the increase in IL2 producti on as T cell growth factor but due to the enhancement in the responsiv eness of PBL to mitogen.