<prompt> Antigen part that is attached to antibody -EpitopeParatopeIdiotypeAllotype  <response>: Ans. is a i.e., Epitope Epitopeo Also known as antigenic determinant.o It is antibody binding site of antigen.Paratopeo The part of the antibody or T cell receptor that interact with the epitope.The idiotype is defined as the specific region of the fab portion of the Ig molecules to which antigen binds. - Harrison 