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 up-regulated in skin metastases of malignant melanoma. The striking regulation of CD44v10 prompted us to generate a murine CD44v10-specific monoclonal antibody to define expression and possible functions of this particular CD44 variant isoform. In the mouse, expression of exon v10 was restricted to basal layers of the epidermis and squamous epithelium of the oral cavity, the esophagus, the omasum, glandular epithelium of the submandibular and the uterine gland, as well as subpopulations of bone marrow cells and activated lymphocytes. Expression started late during development, e.g., was not observed before day 16 of gestation and there was no evidence for developmental regulation of CD44v10 expression. Functional in vivo studies revealed that anti-CD44v10 had no effect on wound healing but inhibited edema and granuloma formation in delayed type hypersensitivity (DTH). Furthermore, lymphocyte-monocyte interactions could be inhibited by anti-CD44v10. Because a CD44v10 transfected tumour line did not show any distinct pattern of cell-matrix or cell-cell adhesion, the data point toward an involvement of CD44v10 in cell migration, possibly by acting as a target structure for cytokines/chemokines provided by the contacted partner cell.