2007 Annual Report 1a.Objectives (from AD-416) To determine the effect of lactobacillus casei strain shirota on the immune response of neonatal pigs. 1b.Approach (from AD-416) Lactobacillus shirota strain will be given to neonatal pigs shortly after birth. The bacteria will be identified in the animal's intestine using molecular probes. Immune tissues will be collected and analyzed for determining changes in immune markers. Treated animals will be compared to control animals. 3.Progress Report This report documents research conducted under a Trust Agreement between ARS and Yakult Central Institute for Microbiological Research, Japan. Additional details of research can be found in the report for the in-house associated project 1235-52000-054-00D, "The Effect of Dietary Probiotics on Immune and Gastrointestinal Function”. The project tested the beneficial effects of probiotic lactic acid bacteria (LAB) on immune and mucosal barrier functions. This study validated the pig as a model for testing the efficacy of Lactobacillus casei strain shirota (LcS) in improving intestinal immune function. Early bacterial colonization of neonatal pigs with the probiotic strain was established by treating piglets immediately after birth. Quantitative measurement of Lactobacillus sp. (tuf gene) at several sites in the gastrointestinal tract indicated that LcS can be detected in the large intestine, achieving its highest concentration as early as the second week after initial treatment. Based on the available information on gene expression generated up to date, LcS seems to induce a generalized “anti-inflammatory state” in animals that have been exposed to LcS. Several genes associated with the early immune activation i.e., Toll-like receptor adaptor molecules like MyD88, CD69, and inflammatory initiators like NFKb1 were down-regulated. Pro-inflammatory genes (IFN-gamma, IL-1) in highly immune reactive sites such as lymph nodes were down regulated. The data suggest that LcS has anti-inflammatory properties that may be useful for the regulation of intestinal inflammatory disorders of the immune system. Conference calls and e-mail correspondences were conducted on a bi-monthly basis with cooperator to review progress.