We created mice expressing transgene-encoded BCRs with "dual reactivity" for the hapten Ars and nuclear autoantigens. Expression of transgene-encoded BCRs was not evident in the memory compartment despite observation of transgene-expressing B cells in germinal centers following Ars immunization. In contrast, dual reactive mAbs were readily obtained from mice with enforced expression of Bcl-2 following secondary Ars immunization. However, while these mAbs were hypermutated and displayed increased affinity for Ars, all had reduced avidity for DNA and intracellular autoantigens. Thus, Bcl-2 alters dominant-negative selection of dual reactive B cells during the Ars response, but this is restricted to those with lowered autoreactivity, demonstrating a hierarchy of peripheral tolerance during memory B cell development.
Bibliographical noteFunding Information:
We thank Dr. Behnaz Parhami-Seren for her assistance in constructing the 36-65/223 and R55/223 mAbs, Dr. Marc Monestier for providing the PL9-6 mAb and hybridoma, Dr. Shailaja Hande for making the transgene constructs used to generate the VR55 and VER55 mice, and Dr. Lesley Lock and the other members of the KCC transgenic/knockout facility. We also thank William Monsell and Kate Dugan for their technical assistance and all other members of the Manser laboratory for their indirect contributions to this work. This study was supported by an NIH grant to T.M. (AI38965). E.N. was supported by NIH training grant AI-07492, and L.H. by NIH training grant CA-72318.