Submitted to: Veterinary Immunology and Immunopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/29/2004
Publication Date: 3/10/2005
Citation: Harp, J.A., Waters, T.E., Goff, J.P. 2005. Adhesion molecule and homing receptor expression on blood and milk polymorphonuclear leukocytes during the periparturient period of dairy cattle. Veterinary Immunology and Immunopathology. 104(1-2):99-103. Interpretive Summary: Mastitis (infection of the mammary gland) is a serious problem in dairy cattle that results in economic losses to producers of over 2 billion dollars annually in the U.S. In this study, we examined granulocytes (white cells that help control infections) in the blood and milk of cows after calving for the presence of adhesion molecules, proteins which allow the cells to move from the blood into the milk. We found that granulocytes in the milk had a different array of these molecules compared with granulocytes in the blood. This suggests that a selected group of these cells move into the mammary gland around calving, and these may influence to degree to which cows are susceptible to mastitis. Understanding the process by which this occurs can lead to ways to better protect cows from mastitis, which will directly benefit the dairy industry worldwide.
Technical Abstract: Homing receptor expression on blood and milk polymorphonuclear leukocytes (PMN) from periparturient dairy cattle was studied. Both percentages of PMN and the mean fluorescence intensity (MFI) on cells expressing adhesion molecules LFA-1 and CD44, the peripheral homing receptor CD62L, and the mucosal homing receptor LPAM-1 (alpha4beta7) were evaluated at seven time points during the 21-day period post-calving. LFA-1 and CD62L were expressed on 94-100% of PMN in both blood and milk and there were no significant differences in these percentages at any time point. LPAM-1 was expressed on 3-10% of the PMN in the blood and 13-45% in the milk and the percentage of cells expressing LPAM-1 in milk was significantly (P less than 0.05) greater than in blood at 0, 4, 10, 14, 18 and 21 days after calving. The percentage of milk cells expressing LPAM-1 at day 0 was also significantly (P less than 0.05) greater than seen in milk cells on all subsequent days. CD44 was expressed on 11-39% of the PMN in blood and 33-69% in the milk and the percentage of cells expressing CD44 in milk was significantly (P less than 0.05) greater than in blood at all time points. In addition, the percentage of milk cells expressing CD44 at day 0 was significantly (P less than 0.05) greater than seen in milk cells on days 4 and 7. The MFI of CD44, CD62L, and LPAM-1 was not significantly different between PMN from blood and milk. The MFI of LFA-1 on milk PMN was consistently higher than that of blood PMN throughout the study period and significantly (P less than 0.05) higher at days 4, 10 and 18 after calving.