Allotopes are regions on an antibody which have non-varying structures. Contrast this with idiotopes which have varying structure from one antibody type to another. ...
<immunology> The structural region of an antigen that distinguishes it from another allotype of that antigen. ... (15 Nov 1997) ... 
(= allotypic determinant) The structural region of an antigen that distinguishes it from another allotype of that antigen.
Type: Term Pronunciation: al′ō-tōp Definitions: 1. A polymorphic region constituting antigenic determinant on the constant region of an allotype.