Three dimensional structure of a functional internal image.

An anti-idiotypic antibody has been characterized that forms a functional internal image of the cell-attachment site of reovirus type 3. This antibody shares sequence similarity with the reovirus type 3 cell attachment protein. Studies utilizing synthetic peptides have shown that the region of sequence similarity corresponds to the cell-attachment site of the virus and the antibody. Studies are described demonstrating that these peptides possess biological activity similar to that of the virus and the antibody. Three-dimensional models of the cell-attachment site of the virus are presented and compared to a similar model for the antibody. These studies indicate that anti-idiotypic antibodies can be utilized to understand the three-dimensional basis of ligand - receptor interactions, and can lead to the development of novel biologically active substances.