Recombinant bovine interferon gamma inhibits the growth of Cowdria ruminantium but fails to induce major histocompatibility complex class II following infection of endothelial cells.
Recombinant bovine interferon gamma (IFNγ) is a potent inhibitor of C. ruminantium growth in vitro, irrespective of the rickettsial stock, or the origin of the endothelial cells. These results suggest an important role for IFNγ in protective immune responses against C. ruminantium infections. Here it is also shown that IFNγ can induce the expression of major histocompatibility complex (MHC) class II molecules on the surface of endothelial cells. However, treatment of endothelial cells with IFNγ following infection with Cowdria fails to induce MHC class II expression. The implications of this pathogen-specific effect on class II expression by endothelial cells with regard to its recognition by the host immune system are discussed.