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.