Energy deficits suppress both systemic and gut immunity during infection.

Protein-energy malnutrition and gastrointestinal nematode infections widely coexist in developing countries. Evidence is provided demonstrating the profound impact of dietary energy deficiency on immune function. Energy-restricted (ER) mice infected with a gastrointestinal nematode showed impaired lymphocyte proliferation and reduced production of Th2 cytokines and lower levels of IgE, parasite-specific IgG1, and eosinophils, which led to higher worm burdens and fecundity. We conclude that mild ER, without concurrent protein malnutrition, can modulate protective immunity from (a) activation early during a primary infection to (b) the expression of acquired immunity during reinfection in both systemic and gut-associated lymphoid tissues. Copyright 1999 Academic Press.