Sodium periodate-induced suppressor cell function in short and long-term calorie restriction

Abstract

To study the effect of calorie restriction on the suppressor function of sodium periodate-treated spleen cells, C57BL/6 mice were distributed one week after weaning into two groups. The control normal group (N) was fed ad libitum a normal diet and the calorie restricted group (R) received on a daily basis 60% of the average food intake of the N group for 3 to 10 weeks. Following in vivo primary immunization with sheep red blood cells (SRBC) i.p., the number of nucleated spleen cells and of plaque forming cells (PFC) per spleen was significantly diminished in the R mice but the proportion of PFC per 10 7 spleen cells was similar in either group. Pretreatment with sodium periodate induced significant suppression of the PFC response of N spleen cells to in vitro stimulation with SRBC but did not depress significantly the PFC response of spleen cells from mice kept on the restricted diet for either 3 or 10 weeks. Addition of 2×10 6 periodate-treated N spleen cells to cultures of 10 7 fresh spleen cells from normally fed mice, markedly suppressed the PFC response in all the experiments, whereas addition of similar number of periodate-treated R spleen cells caused less suppression of the PFC response. The results demonstrate that periodate-induced suppressor cell activity is impaired in short or long-term calorie restriction.