TNF and infection: These results suggested an anti-apoptotic activity in cells infected with Simkania. Time course experiments showed time-dependent resistance for TNF/Chx-induced apoptosis at a multiplicity of infection (MOI) of 0.5 beginning at day 1 p.i. and was similar to non-treated cells at day 3 with <10% apoptotic cells (Figure 2A, B).