Submitted to: Conference Research Workers Disease Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 11/12/2002
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Mastitis in dairy cattle remains a major problem, mainly due to the multitude of microorganisms that can cause the disease. Infection of the mammary gland results in migration of lymphocytes and neutrophils into the affected area. Our objective is to determine mechanisms that regulate trafficking of cells into the mammary gland. As a first step to achieve this, we are using an in vitro assay to compare the adherence of bovine blood and milk lymphocytes to high endothelial venues (HEV) within lymph nodes. Because homing receptor mechanisms are conserved across species, bovine lymphocytes will adhere in vitro to murine tissue sections. We isolated lymphocytes from bovine blood or milk, labeled one or the other population with the fluorescent dye H33342 to distinguish them, and incubated a mixture of both cell types on frozen sections of murine mesenteric lymph node. This allows a comparison of the relative ability of blood and milk lymphocytes to adhere to HEV. Initial studies suggest that the two populations adhere about equally well. However, the present purification methods for milk lymphocytes result in a lower percent of viable cells (50%) than that achievable with blood lymphocytes (95%). Thus, the presence of large numbers of dead milk lymphocytes may interfere with the ability of one or both populations to adhere to the tissue. We are working to increase the yield of viable milk lymphocytes, thereby allowing for more precise evaluation of the in vitro binding events.