2006 Annual Report 4d.Progress report. This report serves to document research conducted under a trust agreement between ARS and Bio-Cis Pharma, LTD. Additional details of research can be found in the report of the parent project 1265-32000-065-00D. A pharmacokinetic study was completed investigating the distribution and half-life of cis-urocanic following intramammary infusion. A pilot study investigating the effect of cis-urocanic acid on mastitis induced by Escherichia coli was also completed. The data from this pilot study indicate a potential beneficial effect of cis-urocanic acid in reducing excessive leukocyte recruitment. This research continues to support the objectives of its related in-house project of developing methods for modulating mammary gland cell-mediated and humoral immune responses (Objective #1).