MAD-CT-2 identified as a novel melanoma cancer-testis antigen by high throughput immunoblot Free

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A major focus in the field of tumor immunology is the identification of cancer antigens that might be exploited as therapeutic targets or as immunological diagnostic markers. Cancer-testis antigens (CTA) are of particular interest as potential tumor antigens given that their expression is typically restricted to germ cells among normal tissues, but aberrantly expressed in multiple tumor types. In the current study, we wished to develop a tool that could be used to rapidly evaluate antibody immune responses to a defined panel of CTA, using a single small-volume serum sample. We report the construction of a panel of 29 CTA in lambda phage, and a high throughput immunoscreening method. This was tested using a panel of sera from patients with melanoma (n=56) and volunteer blood donors (n=50). We found that antibody responses occurred in 38% of patients with melanoma to at least one of these antigens compared with 4% of controls (p < 0.001), suggesting that antibody-based diagnostic panels could be developed using similar methods. Moreover, antibody responses to one antigen, MAD-CT-2, occurred in 25% of patients compared with 0/50 controls (p < 0.0001). These findings, along with the demonstration that MAD-CT-2 is expressed in melanoma cell lines, identified MAD-CT-2 as a novel melanoma CTA.