KRISTAN, D.M.*; MANIBUSAN, P.T.; ALVARADO, I.; California State Univ., San Marcos; California State Univ., San Marcos; California State Univ., San Marcos: Chronic caloric restriction increases susceptibility of laboratory mice to infection with the intestinal nematode Heligmosomoides polygyrus

Numerous benefits of chronic caloric restriction (i.e. undernutrition without malnutrition) have been repeatedly demonstrated for a wide array of vertebrate and invertebrate species. One benefit shown for laboratory mice (Mus musculus) is enhanced immune system function. Enhanced immune function is typically demonstrated by introducing foreign antigens into laboratory mice and measuring subsequent immune response. These early studies uniformly concluded that calorically restricted mice had better immune function. However, recent work that used whole pathogens (bacteria and viruses) to elicit an immune response reveals mixed results where calorically restricted mice sometimes fare less well than ad libitum fed mice. We examined effects of chronic caloric restriction in laboratory mice on susceptibility to experimental inoculation with a macroparasite, Heligmosomoides polygyrus. We predicted that mice subjected to four months of caloric restriction would have enhanced immune function and therefore would be more resistant to primary and secondary infections of H. polygyrus compared to fully fed mice. Contrary to our prediction, preliminary data indicate that calorically restricted mice were more susceptible to both primary and secondary nematode infection than control mice. Furthermore, the nematodes themselves had greater egg output when living in a calorically restricted host during primary but not secondary infections. Current studies are being done to measure specific immune factors produced by chronically calorie restricted and ad libitum fed mice during primary and secondary H. polygyrus infections.