Molecular analysis of induced idiotypes associated with autoanti-thyroglobulin

Idiotype (Id) and autoanti-thyroglobulin were induced in different strains of mice by priming with anti-Id to monoclonal anti-thyroglobulins (D8 and G4) and challenged with a subimmunogenic dose of thyroglobulin (Tg). Both D8.Id and G4.Id were induced in CBA mice by priming with the appropriate anti-Id, but only priming with anti-D8.Id also induced an increase in anti-Tg. D8.Id was induced in other strains by the same schedule but it only appeared to be associated with anti-Tg in 129 and, to a lesser extent, BALB/c mice, both of which have the allotype Iga. The extent of the overlap between the D8 Id and the anti-Tg was estimated and shown to be greatest in the CBA strain from which the D8 clone was originally derived. Spectrotypic analysis of the induced Ids in CBA mice showed that some of the D8.Id, but none of the G4.Id, was identical to the original clonotype, implying that CBA mice normally have cells which can be induced to produce D8.Id-positive autoanti-Tg, which are normally weakly expressed or regulated. The observation that anti-D8.Id priming in some strains increased D8.Id-negative anti-Tg responses suggests that the D8.Id may also be associated with anti-Tg T-cells.