This location differs from the one of a previously reported idiotope from an anti-idiotypic antibody able to activate [CD8.sup.+]T cells, which was located in the NH2-terminal [V.sub.H] region, before FR1 .
Perez Rodriguez, "A monoclonal antibody against NeuGccontaining gangliosides contains a regulatory idiotope involved in the interaction with B and T cells," Molecular Immunology, vol.
Some of these antibodies (P3-I[d.sup.+]) carry a regulatory idiotope able to bind anti-idiotypic B cells, B-1a [alpha]P3-Id, and B-2 [alpha]P3-Id (2).
The levels of anti-3-FL antibodies and the crossreactive idiotope were comparable to those in conventional animals.
That suggested that the idiotypic determinants (idiotopes) are related to the anti-3-FL binding site.
To obtain insight into the remarkable immunogenicity of the 3-FL determinant in mice, we examined the occurrence of anti-3-FL antibodies and crossreactive idiotopes in the sera of unimmunized and immunized mice.
Fab, the variable region of an immunoglobulin, containing the antigen combining site and idiotope.
They may, however, show activity against idiotopes, which are not present in nonimmune globulin (8), or against conjugated detector antibodies (8,18).
If this is true, we also would assume that the HAMAs insensitive to MAK33 are directed against allotypic or idiotypic epitopes (idiotopes) not related to the isotype of the Ig[G.sub.1[kappa]] antibodies.
Although allotypic epitopes can be expressed by many IgG molecules independent of their isotype, idiotopes that are formed by the variable region on the Fab portion mostly are unique epitopes.