Currently, studies requiring a pool of mostly-infected cells rely on infections performed with an m.o.i that is sufficiently high to infect the majority of cells exposed to Chlamydia. Indeed, our finding that the IFNγ-induced expression of IDO1 is suppressed within infected cells was confirmed using conditions in which >95% of Chlamydia-exposed cells were infected. The gene discussed is IDO1; the disease is infection.