- Gamma interferon fails to induce expression of indoleamine 2,3-dioxygenase and does not control the growth of Chlamydophila abortus in BeWo trophoblast cells. Entrican, G., Wattegedera, S., Chui, M., Oemar, L., Rocchi, M., McInnes, C. Infect. Immun. (2002)