Role of CD8(+) and WC-1(+) gamma/delta T cells in resistance to Mycobacterium bovis infection in the SCID-bo mouse

The role of various effector T cell populations in the bovine immune respon se to Mycobacterium bovis infection is poorly understood, This is largely d ue to the difficulties associated with performing in vivo challenge studies in the natural host species. in this report, we utilized a fetal bovine-se vere combined immunodeficient (SCID-bo) xenochimeric mouse model to study t he protective role of two putative effector cell types, CD8(+) T cells and a subpopulation of gamma/delta T cells that express WC-1, a member of the c ysteine-rich scavenger receptor superfamily (CRSR). We demonstrate that CD8 + T cells play a hey role in protection and contribute substantially to bov ine IFN-gamma mRNA levels at 30 days post-infection. The role of WC-1 beari ng cells to protection Tvas less definitive but our results suggest that th is population may play a pivotal role early in infection. Granuloma archite cture was altered in anti-WC-1 (ILA29) but not anti-CD8 (ILA51)-treated ani mals, suggesting that this population may be involved in recruitment of var ious cell types to sites of infection.