An increasing number of functional foods and pharmaceutical preparations containing lactic acid bacteria are being promoted with health claims based on the potential probiotic characteristics and on their capacity for stimulating the host immune system. However, the specific immune effects of oral administration of these microbes remain undefined. In this study, we tested the hypothesis that basal gastrointestinal immune status in mice is affected by orally administered lactic acid bacteria. The specific objective of this research was to evaluate the effects of repeated oral exposure to viable and nonviable lactic acid bacteria (Lactobacillus acidophilus, L. bulgaricus, L. casei, and Streptococcus thermophilus) in mice on basal cytokine mRNA expression in mucosal (Peyer's patches), systemic (spleen), and lymphoid tissue and on immunoglobulin levels. The results indicated that oral exposure to 109 CFU/day for up to 14 days did not significantly affect basal interferon-γ, tumor necrosis factor-α, or interleukin-6 mRNA expression or total serum and intestinal immunoglobulins.

This content is only available as a PDF.