Sheep CD1 genes and proteins

Interest in CD1 genes and proteins was initially stimulated by their close evolutionary and structural relationship to MHC class I molecules. The demo nstration that CD1b and c molecules present novel non-peptide antigens to T -cells and play a role in protection against mycobacterial infection then f ocused attention on the functional role of CD1 proteins. Sheep possess at l east seven CD1 genes, including CD1B, D and E, which is the most complex ge netic arrangement identified so far in any animal. OvCD1B consists of at le ast three distinct genes, with the probability of limited polymorphism and the existence of splice variants. Most anti-sheep CD1-specific monoclonal a ntibodies react with OvCD1b and phenotypic and immunochemical data suggests the existence of two variants. CD1D genes have been identified in all spec ies studied, suggesting a conserved role for CD1d proteins across mammalian species. Presumptive evidence for the existence of OvCD1E has been obtaine d by NH2-terminal sequencing of protein precipitated by the mAb 20.27 (SBU- T6). Confirmatory evidence from gene cloning experiments is currently being sought. Collectively, these factors make the sheep CD1 family a highly rel evant model for investigating the in vivo role of CD1 molecules. In this su rvey, the properties of monoclonal antibodies specific for sheep CD1, the c ellular distribution and physicochemical characteristics of sheep CD1 molec ules and the current state of knowledge on sheep CD1 genetics are reviewed. (C) 2000 Elsevier Science B.V. All rights reserved.