Immunohistochemical localization of adhesion molecules (CD62 and CD18) in the mammary gland of dairy cows

Abstract

Localization of the L-selectin (CD62L) and β2-integrin (CD18) bearing cells in different tissues of the bovine mammary gland was examined. Five dairy cows of Holstein-Friesian breed in the middle of their second and third lactation cycle were used in the study. Blood, milk and udder tissue samples were collected from each cow to estimate the milk somatic cell count (SCC) and bacteriological infection of the mammary gland. The expression of CD62L and CD18 on blood cells, milk cells and parenchymal tissues of udder, Fürstenberg’s rosette and the transverse section of the central part of the teat was tested. In the mammary gland quarters the value of SCC in milk secretion was also reflected in the presence of CD18<sup>+</sup> and CD62L<sup>+</sup> leukocytes in mammary tissues. In the quarters where SCC was higher than 10<sup>5</sup> a frequent incidence of L-selectin and β2-integrin cells was observed in the parenchyma and Fürstenberg’s rosette region, while in the quarters with low SCC, none or only a few reactive cells were found. In the mammary parenchymal tissue CD18 positive cells were present in both the epithelial and the connective tissue. In Fürstenberg’s rosette the cells were concentrated in the connective collagenous and loose tissue. None or only scattered L-selectin (CD62L) and β2-integrin (CD18) bearing cells were identified in the transverse section from the central part of the teat. When we compared the L-selectin and β2-integrin expression, the study revealed the down-regulation of L-selectin on the cells of mammary tissue.