CD44V10 EXPRESSION IN THE MOUSE AND FUNCTIONAL-ACTIVITY IN DELAYED-TYPE HYPERSENSITIVITY

We have described recently that expression of CD44 exon v10 (CD44v10) is down-regulated upon metastasis of squamous cell carcinoma, whereas it is upregulated in skin metastases of malignant melanoma. The striki ng regulation of CD44v10 prompted us to generate a murine CD44v10-spec ific monoclonal antibody to define expression and possible functions o f this particular CD44 variant isoform. In the mouse, expression of ex on v10 was restricted to basal layers of the epidermis and squamous ep ithelium of the oral cavity, the esophagus, the omasum, glandular epit helium of the submandibular and the uterine gland, as well as subpopul ations of bone marrow cells and activated lymphocytes. Expression star ted late during development, e.g., was not observed before day 16 of g estation and there was no evidence for developmental regulation of CD4 4v10 expression. Functional in vivo studies revealed that anti-CD44v10 had no effect on wound healing but inhibited edema and granuloma form ation in delayed type hypersensitivity (DTH). Furthermore, lymphocyte- monocyte interactions could be inhibited by anti-CD44v10. Because a CD 44v10 transfected tumour line did not show any distinct pattern of cel l-matrix or cell-cell adhesion, the data point toward an involvement o f CD44v10 in cell migration, possibly by acting as a target structure for cytokines/chemokines provided by the contacted partner cell. (C) 1 997 Wiley-Liss, Inc.