Variation idiotypic

A large body of data has been amassed indicating that the structure of antibodies elicited by a T cell dependent form of an antigenic determinant varies substantially in comparison to a T cell independent form of the same determinant. The variation in predominant isotypic class of antibody elicited by T dependent as well as independent antigens is well documented (reviewed in [146]). Expression of idiotypic determinants by the elicited antibody population has been observed to differ substantially in responses to T cell dependent and independent forms of the same haptenic determinant [147]. The participation of T cells during a humoral immune response clearly influences the structure of the antibodies elicited. 

Additional evidence for the importance of antigenic valence is the finding of Potter et al. (34) and Potter and Lieberman (35) that Fab fragments of mouse myeloma proteins often fail to precipitate with antiidiotypic antibodies which form precipitates with the intact myeloma protein. Also, Harboe et al. (36) reported inhibition of the precipitation of monoclonal IgM by its antiidiotypic antiserum in the presence of the 7 S subunit of the IgM the latter would necessarily have a lower antigenic valence. Increased precipitability by the indirect method has also been observed in quantitative studies of certain rabbit allotypic specificities (37). The fact that Fab fragments sometimes form precipitates with antiidiotypic antibodies and sometimes inhibit precipitation is attributable to variation in the number of idiotypic determinants recognized by different antisera. 

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