Monoclonal anti-androgen receptor antibodies: Production, characterization, and potential diagnostic applications

Several monoclonal antibodies (mAbs) and novel mAb-based assays for the and rogen receptors (AR) have been developed. Large amounts of the recombinant human AR protein produced by a baculovirus expression system were used as a n antigen to produce mAbs. Twenty-nine AR-specific mAbs were first confirme d by Western blot analysis and were then characterized for their immunoglob ulin isotypes, epitopes, and epitope localization in AR. Novel assays using flow cytometry and sandwich enzyme-linked immunosorbent assays (ELISA) wer e established to detect AR-expressing cells and to quantify soluble AR prot ein, respectively. Using immunostaining, we identified several anti-AR mAbs exclusively recognizing AR within the nuclei of the prostate cancer cell l ine LNCaP and of prostate tissues in both frozen and paraffin-embedded sect ions, whereas other mAbs could detect AR in both nuclear and cytoplasmic co mpartments. Interestingly, certain mAbs, such as G122-25 and G122-77, could distinguish the androgen-bound AR from the unoccupied AR. In sum, many pur ified AR protein and anti-AR mAbs, together with the assays developed, coul d be powerful tools for the study of functional AR and for the diagnosis of prostatic cancers.