Effect of protein and zinc deficiencies on vaccine efficacy in guinea pigs following pulmonary infection with Listeria.

Specific pathogen-free guinea pigs were maintained for 3 weeks on purified diets containing 30% protein (ovalbumin) and 50 ppm added zinc (Control-C), 10% protein and 50 ppm added zinc (low protein-LP), or 30% protein and no added zinc (low zinc-LZ). Half of the animals in each diet group were vaccinated intraperitoneally with 2.5 x 10(3) viable Listeria monocytogenes organisms after 8 days of diet treatment. Ten days later, all animals received an aerosol challenge of 250 L. monocytogenes organisms and were killed 4 days later. Both zinc and protein deficiency resulted in animals that were growth retarded as compared to controls. Specific nutrient effects were observed as significant reductions in total serum proteins (LP group) and plasma zinc concentrations (LZ group). In vaccinated guinea pigs, both protein and zinc deprivation resulted in significant impairment of delayed-type hypersensitivity (DTH) responses following the intradermal injection of listeria antigen. Diet did not exert a measurable impact on the response of nonvaccinated guinea pigs to pulmonary listeriosis. Prior vaccination allowed both malnourished groups to control the challenge infection successfully as measured by significant reductions in viable bacilli recovered from the lung, spleen and hilar lymph nodes. The diet and vaccine effect varied depending on the tissue examined. Thus, although both protein and zinc deficiencies resulted in loss of peripheral antigen-specific T lymphocyte function (DTH), vaccine efficacy was not impaired.