variable region

noun

, Immunology.

1. a configuration in the upper branches of the Y of an antibody molecule, unique in each antibody type, that binds with the determinant of a specific antigen.

variable region

1. The portion of the amino (NH 2 ) terminal of an antibody's heavy and light chains having a variable amino acid sequence. The structure of the variable region determines the antigenic specificity of the antibody.
2. Compare constant region