Paratope of OC125 antibody (OC125 paratope)

A paratope is the antigen-binding region of an antibody, consisting of specific residues within the variable regions of the antibody’s heavy and light chains that make direct contact with the epitope on the antigen. In the OC125 monoclonal antibody, the paratope recognizes a conformational epitope found within tandem repeat domains of the CA125 (MUC16) molecule[1][7]. Detailed structural mapping shows that the recognized epitope is conformation-dependent, not solely reliant on glycosylation, and lies across segments that may involve two consecutive SEA (sea urchin sperm protein, enterokinase, agrin) domains of MUC16[7]. The actual amino acid sequence of the OC125 paratope is not standardized in public references, and the antigen-binding specificity underpins the use of OC125 in diagnostic tests for CA125 antigen, but the paratope itself is not a therapeutic nor diagnostic target[3][7].

Other names

antigen-binding site of OC125OC125 antibody paratope