Lack of MHC expression and retention of ultrastructural characteristics by xenograft transmissible venereal tumor cells in SCID mice

Canine transmissible venereal tumor (CTVT) is primarily a tumor of adult dogs with a high incidence of spontaneous regression. We recently reported a xenograft model of CTVT (XTVT) in NOD/SCID mice. XTVT cells retain cytological and histological features of CTVT as well as characteristic rearranged LINE/c-MYC junction [Am. J. Vet. Res. 62 (2001) 907]. In this paper, we demonstrate that XTVT cells maintain ultrastructural characteristics of CTVT and do not express MHC classes I and II molecules.