Modulation of delayed-type hypersensitivity and acquired cellular resistance by orally administered viable indigenous lactobacilli in Listeria monocytogenes infected Wistar rats

Aims: Various probiotic lactobacilli have been reported to modulate immunity. In this study we investigate the effects of viable indigenous Lactobacillus strains Utr-1, Utr-2 and Utr-3, on T cell-mediated immunological memory responses. Methods and Results: In Listeria monocytogenes infected rats it was demonstrated that short-term daily ingestion of Lactobacillus strain Utr-3 significantly decreased delayed-type hypersensitivity (DTH) expression, whereas long-term, daily oral administration of Lactobacillus strain Utr-3 and Lactobacillus strain Utr-2 significantly enhanced acquired cellular resistance (ACR) towards Listeria re-infection. Conclusions: Our findings demonstrate that certain indigenous Lactobacillus strains are capable of modulating T cell-mediated immunity. Significance and Impact of the Study: Our results support the importance of indigenous microflora analysis in probiotic lactobacilli studies.