Figure 2. SIM2 elicits spontaneous humoral responses in PCa patients.

Sera from 9 PCa patients and 5 healthy donors were subjected to an in vitro, cell-free protein expression-based ELISA to detect auto-antibodies to SIM2. SIM2 was expressed as a GST-tagged protein and an anti-GST-coated plate was used in the assay. Serum antibodies that bound to immobilized SIM2 were detected using a labeled anti-human antibody. In each assay, wells containing a GST-expressing vector were used as a negative control. Signals obtained from GST wells were substracted from those obtained from wells that contained GST-SIM2. Three experiments were performed, with triplicate wells for each serum sample per experiment. Statistics were performed on the triplicates’ mean and SD, and antibody amounts are plotted here as the difference of OD signals produced by GST-SIM2 and GST alone. ** P<.01.