Expression and localization of rabbit B-cell activating factor (BAFF) and its specific receptor BR3 in cells and tissues of the rabbit immune system.

Rabbits are widely used for vaccine development, and investigations of human infectious and autoimmune diseases such as Systemic Lupus Erythematosus (SLE). For these applications, we cloned, sequenced and expressed rabbit B-cell Activating Factor (BAFF), and localized BAFF in cells and tissues of the rabbit immune system. The rabbit homolog of the human BAFF binding site (miniBR3 peptide) within the BAFF-specific receptor BR3 was synthesized. This 26-residue core domain binds to recombinant rabbit BAFF protein. Flow cytometric analyses using purified recombinant rabbit BAFF combined with real-time PCR findings revealed that BAFF detected on peripheral blood B-cells from normal rabbits is probably complexed to BAFF receptors rather than produced by the B-cells. BAFF was detected in developing appendix of young rabbits by immunohistochemical staining suggesting that BAFF plays a role during the period following birth when rabbit B-cell development and pre-immune antibody repertoire diversification and selection is occurring.