We used Acro Biosystems' recombinant Human CA125 / MUC16 protein (Catalog #CA5-H52H6) as a target antigen for antibody screening and downstream validation. The protein was employed in both ELISA and FACS assays. In ELISA, we observed strong, dose-dependent binding with minimal background, which enabled clear differentiation of candidate clones. For FACS, we used the protein to confirm surface staining specificity on engineered cell lines, and the results were consistent and reproducible. I was particularly impressed with the proteins high purity.