Tetraparental rabbits chimeric for their lymphoid system--I. Allotype expression

Idiotypic relationships between allotypically different rabbit antibodies

Homozygous rabbits genotypically different for the allotypy of the VH region and the C kappa region of their immunoglobulins (al/al, b4/b4 and a3/a3, b5/b5, respectively) were transferred together at the blastocyst stage to be born from the same foster mother. At the time of transfer the foster mothers were active anti-anti-idiotypic (Ab3) antibody producers and, according to their own genotype, the idiotypes (Ab1) which initiated the immunization cascade ending with their Ab3 were allotypically either a1,b4 or a3,b5. This experimental scheme was carried out, at the level of the Ab1 and of the Ab'1 (antibodies produced by the transferred rabbits subjected to the Ab3 action), with three different exogenous antigens, namely a protein, a polysaccharide and a hapten which elicited in normal rabbits the production of antibodies with private idiotypic specificities. Two of them, the protein and the polysaccharide enabled us to find idiotypic relationships between antibodies totally different for their allotypy and particularly for the allotypy of the variable region of their heavy chains. In these examples, the structural coercions implied by the different allotypic markers of the VH did not seem to prevent the association of at least related genetic elements responsible for the observed idiotypic community. In these idiotypic relationships, only subpopulations of the Ab1 and of the Ab'1 were implicated and they could be different for the diverse littermates.

Tetraparental rabbits chimeric for their lymphoid system--II. Idiotype expression

In order to test some aspects of the network theory of "idiotype-anti-idiotype" interactions, we studied the idiotypic specificities of anti-DNP antibodies produced by tetraparental rabbits, chimeric for their lymphoid system, under two different experimental conditions. In the first, the tetraparental rabbits were simply immunized against the hapten and we observed that the antibodies, totally different in their allotypy, produced by the lymphocytes of the two constitutive parental strains remained idiotypically independent in three cases out of three. In the second experimental regimen, the tetraparental rabbits underwent an anti-anti-idiotypic immunization before the anti-hapten one. In two out of the four cases studied we observed that anti-DNP antibodies different in their a- and b-series allotypic specificities can bear at least related idiotypic specificities.