Regulation effect of CD137 and CD28 on aged T cell activation

Objective To investigate the effect of co-stimulatory molecular CD137 and CD28 on the cell proliferation, IL-2 secretion and cell apoptotic rate of activated T cells in naturally senile mice and subacute senile mice induced by D-galactose. Methods Seven-week-old BALB/c male mice were divided into D-galactose induced subacute senile group (D-gal group) , control group and young group randomly. Subacute senile mice model was established by back hypodermic injection of D-galactose (120 mg/kg, dissolved in 0. 1 ml distilled water) everyday for five month. Control group was established by injection of 0. 1 ml distilled water everyday for five month. Young group was injected with nothing. And 16-month-old BALB/c male mice was taken as aged group. The spleen T cells of each group were isolated and activated in vitro stimulation with ConA + IgG, ConA + CD137mAb or ConA + CD28mAb. The cell proliferation, apoptotic rate and IL-2 concentration in cell culture supernate of T cells were detected. Results (1) The cell proliferation (0.422±0.057, A), IL-2 secretion(0.632±0.066, A)and apoptotic rate(68.0%±2. 4%) of T cells in D-gal group stimulated in vitro with ConA+IgG showed no significant difference when compared with those of aged group. Compared with young and control group, activation of T cell in D-gal and aged groups were significantly decreased; (2) Cell proliferation, IL-2 secretion and cell survival of T cells in D-gal group and aged group were significantly promoted by both ConA + CD137mAb [(0. 639±0. 053, A) , (1.119±0.035,A), (53.3%±2.4)%, respectively] and ConA +CD28mAb. CD137 mAb had less effect on both groups than did CD28 mAb. Conclusions (1) Similar age-associated alterations happen in T cells of both D-gal group and aged group. (2) CD137 and CD28 can promote the activation and survival of T cells in aged and D-gal group. But CD28 has stronger effect on regulation of T cells than CD137.