anti-idiotype antibody 

Antibody idiotope— the unique set of antigenic determinants of the variable region of an antibody. The idiotype represents the variable part of an antibody, including the unique antigen binding site, and the combination of epitopes within the idiotype (i.e., the idiotopes) is unique for each antibody. https://www.creative-biolabs.com/Production-of-Anti-idiotype-Antibody.html