Tg(Igh-CD40)1Kik

A wild-type human CD40 cDNA was inserted into an expression cassette containing the mouse immunoglobulin M heavy chain enhancer (Em), the promoter from a rearranged mouse immunoglobulin heavy chain gene, and the rabbit beta globin gene, including an intron and the polyadenylation signal. Flow cytometric analysis of transgenic spleen cells demonstrated expression of the transgenic protein on B220+ B lymphocytes, at levels similar to those of endogenous CD40 on wild-type B cells; however, human CD40 is not expressed on other antigen presenting cells that normally express native CD40. Furthermore, CD40 expression from the transgene is not down-regulated following antigen-induced differentiation of immature B cells into plasma cells, but remains at high levels in CD138+, antibody-producing cells. (J:113575)