Meeting Abstract

P2.34  Wednesday, Jan. 5  Calorie restriction increases mouse immune response but does not decrease susceptibility to repeated parasite inoculations LANG, S.A.*; KRISTAN, D.M.; California State University San Marcos lang014@cougars.csusm.edu

Long-term calorie restriction (CR) enhances the immune response of laboratory mice (Mus musculus). Despite this increased immune response, CR mice are more susceptible to primary or secondary nematode infections. It is unknown if long-term CR affects susceptibility to repeated exposures of parasites, which most closely mimics the pattern of human parasite exposures. We tested the effects of CR on immune response and parasite susceptibility for laboratory mice given repeated inoculations with the intestinal nematode Heligmosomoides bakeri. We hypothesized that CR mice would have a greater immune response but also take longer to rid themselves of H. bakeri worms. CR mice were fed 40% fewer calories than ad libitum (AL) mice for six months. All mice then received a series of 5 inoculations of 50 H. bakeri larvae every 10 days. We monitored fecal egg output as an indicator of relative worm number. Blood was sampled before the first inoculation, at the third and fifth inoculation, and 24 days after the fifth inoculation to measure H. bakeri specific immunoglobulin G1 (IgG1). At dissection, we measured the number of splenic CD4+ T cells and counted and measured worms. We found that CR mice had more CD4+ T cells and similar levels of parasite specific IgG1 compared to AL mice. Despite the strong T cell response by CR mice, we found no difference in worm numbers or worm length, and female worms taken from CR mice produced more eggs in vivo during the first 34 days post-infection compared to worms from AL mice. These results indicate that the strong adaptive immune response of CR mice that develops upon repeated exposure to H. bakeri is not capable of decreasing susceptibility to infection for mice subjected to long-term calorie restriction.