Interaction ofYersinia pestiswith Macrophages: Limitations in YopJ-Dependent Apoptosis

Caspase-1 Activation in Macrophages Infected with Yersinia pestis KIM Requires the Type III Secretion System Effector YopJ

“…KIM5 yopJC172A was also defective for inhibiting TNF-␣ secretion from infected BMDMs, as expected from previous results obtained with Y. pestis EV76 (Fig. 9E) (56). Taken together, our results demonstrate a novel role for the YopJ protein of Y. pestis KIM strains in activation of caspase-1 in macrophages.…”

“…In addition to analyzing IL-1␤, we also measured secretion of IL-18, which is dependent upon cleavage by active caspase-1 for its processing and release, and of TNF-␣, which is not. A previous study has shown that Y. pestis strain EV76 can partially suppress secretion of TNF-␣ from infected RAW264.7 macrophage-like cells and that YopJ is required for this suppression (56). BMDMs were infected with KIM5 or KIM5 yopB, supernatants were collected at various time points, and ELISA was used to measure levels of secreted IL-1␤, IL-18, and TNF-␣.…”

Manipulation of Interleukin-1β and Interleukin-18 Production by Yersinia pestis Effectors YopJ and YopM and Redundant Impact on Virulence

“…3A). Notably, the CO92 strain carries a variant of YopJ that is less catalytically active than the KIM1001 variant (10,38,39). It is possible that this variant of YopJ in CO92 partially unmasks the contribution of YopM to virulence.…”

Yersinia pestisCan Bypass Protective Antibodies to LcrV and Activation with Gamma Interferon To Survive and Induce Apoptosis in Murine Macrophages

“…pestis than macrophages treated with IFN-␥ alone (22). Previous studies have shown that Y. pestis can partially suppress the secretion of TNF-␣ from infected macrophages and that YopJ is required for this suppression (21,46). Lilo et al showed that after 24 h of infection, ϳ2,000 pg/ml TNF-␣ was released by KIM5-infected BMDMs (21).…”