The effect of green tea extracts on lymphocyte proliferation: A study in mice inoculated with Listeria monocytogenes

Abstract

Elimination of L. monocytogenes in spleen and liver were dependent on CD4 and CD8 T cells. Since previous studies had shown that green tea extract (GTE) stimulated the production of IL-12, IFN-g, and TNF-a, this recent study was aimed to prove that GTE could induce lymphocyte proliferation. Balb/c mice were randomly divided into 11 groups, each group consisted of 5 mice. Group I, the mice were not given green tea nor bacteria. Group II, the mice were not given tea but they were inoculated with L. monocytogenes. Group III to V, the mice were treated with green tea polyphenon-60 in different doses (1.5, 3, and 6 mg/day). Group VI to VIII, the mice were treated with EGCG (0.5, 1, and 2 mg/day). Group IX to XI, the mice were treated with EGC (0.15, 0.3, and 0.6 mg/day). The mice in group III to XI were treated with those GTE orally for 14 days. They were inoculated with 10⁴ L. monocytogenes intra peritoneally on the 10^th day. All the mice were sacrificed on day 15 to examine the number of lymphoblasts in spleens. The results revealed that the number of lymphoblasts increased in all groups of mice treated with green tea polyphenon-60, EGCG, and EGC. Green tea polyphenon-60 had the highest effect to increase the number of lymphoblasts in mice inoculated with L. monocytogenes. It was concluded that green tea extracts could induce lymphocyte proliferation.