Adhesion Molecules and the Cellular Population of the Normal Camel (Camelus dromedaries) Mammary Glands

ABSTRACT

The demand to camel's (Camelus dromedaries) milk is increasing worldwide. The new advances in the dairy industry have made the camel milk production on the commercial level is possible. The camel mammary glands immune system is not explored in detail. This study was conducted to identify the cell adhesion molecules involved in the regulation of the cells trafficking to the camel mammary glands at two different physiological stages; lactation and nonlactating periods. The expression and distribution of CD markers and the adhesion molecules, CD4⁺, CD8⁺, MAdCAM-1, WC+1⁺, CD62L, CD11a/CD18 (LFA-1), VCAM-1, TCR-αβ, CD44⁺ and CD20⁺ in the alveolar tissues, supramammary lymph nodes, Peyer's patches and mesenteric lymph node of the healthy camels were explored. The expression of the adhesion molecules was determined in situ by immunohistochemical technique using immunoperoxidase staining. MAdCAM-1 was detected in almost all the tissues at the two physiological stages in which high expression was evident in the non-lactating period. CD8⁺ T-cells were detected in both mammary alveolar tissues and the supramammary lymph nodes, with the highest expression observed in the lactating period. WC+1⁺ expression on γδ cells were evident in mammary tissues and supramammary lymph nodes at both stages; however, the expression was higher in the non-lactating period. The detection of CD20⁺, CD62L, VCAM-1, TCR-αβ, and CD44⁺ expression failed despite their expression in the original species that the antibodies were raised against. The expression of CD4⁺ and CD11a/CD18 (LFA-1) were not detected at all.

The intensive expression of the MAdCAM-1 in the camel mammary glands could indicates that camel mammary glands cells trafficking is closely linked to the intestinal immune system (mucosal) rather than peripheral as it is well known for the bovine mammary glands. The high expression of WC+1⁺ strongly reflects the importance of these cells subset in the defense mechanism of the camel mammary glands during the late lactation.

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