Expression of potential lymphocyte trafficking mediator molecules in the mammary glandToshihide Nishimura
Department of Animal Breeding, Faculty of Agriculture, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan
(Received 14 January 2002; accepted 24 June 2002)
The mammary gland performs a variety of immunological functions, including protecting itself from mastitis and protecting neonates from infectious agents. Several molecules that mediate lymphocyte trafficking in the immune system are also expressed in the mammary gland. This review is focused on the immunological function of these molecules, especially glycosylation-dependent cell adhesion molecule-1 (GlyCAM-1) and mucosal addressin cell adhesion molecule-1 (MAdCAM-1) in the mammary gland. GlyCAM-1 is expressed in the lactating mouse mammary gland. Endothelial cells produce this protein and secrete it into milk. The glycosylated modification of mammary gland GlyCAM-1 is different from that of the lymph nodes, and lacks the binding ability for L-selectin on lymphocytes. GlyCAM-1 in the mammary gland is not involved in lymphocyte migration, and probably has another function besides that of the lymph nodes. MAdCAM-1 is expressed on endothelial cells of small venules around mouse mammary lobules during lactation. This molecule has the ability to interact with integrin on lymphocytes and mediates lymphocyte recruitment to the mammary gland. The density of /CD3 + T-cells is correlated with the density of the MAdCAM-1-stained area, suggesting that MAdCAM-1 may mediate the migration of these cells. In contrast, there is no relationship between MAdCAM-1 expression and the number of /c-IgA + B-cells, implying that some other factor is involved in lymphocyte migration to the mammary gland. Chemokines, such as IL-8, GRO- , MCP-1, RANTES and MEC, have been detected in human and mouse mammary glands. Although little information is available, these molecules may contribute to lymphocyte migration to the mammary gland.
Key words: mammary gland / mucosal-associated lymphoid tissue (MALT) / glycosylation-dependent cell adhesion molecule-1 (GlyCAM-1) / mucosal addressin cell adhesion molecule-1 (MAdCAM-1) / lymphocyte migration
Correspondence and reprints: Toshihide Nishimura tel. (81) 52 853 8146; fax (81) 52 842 3955;
© INRA, EDP Sciences 2003