Novel monoclonal antibodies specific for CTLD-SSC and sialomucin domains of endosialin, a mural cell marker of tumor vasculature.

Endosialin, alternatively named tumor endothelial marker or CD248, was originally discovered as an antigen selectively expressed in tumor blood vessels. Subsequent studies showed that it is confined to stromal fibroblasts and pericytes of tumor vasculature rather than to tumor endothelium. Endosialin levels are upregulated in different tumor types including those derived from the brain, colon and breast. Expression of endosialin is associated with tumor growth, progression and correlates with a pro-proliferative and pro-migratory phenotype. However, the function of endosialin and mechanisms of its regulation are still incompletely understood. To facilitate further study of endosialin in angiogenesis, its interaction with the potential binding partners and other aspects of endosialin function, we generated six new domain-specific anti-endosialin monoclonal antibodies. Two of them recognize the C-type lectin-like domain-Sushi/SCR/CCP and four antibodies are directed to the sialomucin domain. The antibodies are suitable for various immunodetection methods including immunoblotting and immunohistochemistry. They represent important tools for improving our understanding of endosialin regulation, biological role and contribution of its extracellular domains to the tumor phenotype.