Cutting edge: caspase-1 independent IL-1β production is critical for host resistance to Mycobacterium tuberculosis and does not require TLR signaling in vivo

KD Mayer-Barber, DL Barber, K Shenderov… - The Journal of …, 2010 - journals.aai.org
KD Mayer-Barber, DL Barber, K Shenderov, SD White, MS Wilson, A Cheever, D Kugler
The Journal of Immunology, 2010journals.aai.org
To investigate the respective contributions of TLR versus IL-1R mediated signals in MyD88
dependent control of Mycobacterium tuberculosis, we compared the outcome of M.
tuberculosis infection in MyD88, TRIF/MyD88, IL-1R1, and IL-1β–deficient mice. All four
strains displayed acute mortality with highly increased pulmonary bacterial burden
suggesting a major role for IL-1β signaling in determining the MyD88 dependent phenotype.
Unexpectedly, the infected MyD88 and TRIF/MyD88-deficient mice, rather than being …
Abstract
To investigate the respective contributions of TLR versus IL-1R mediated signals in MyD88 dependent control of Mycobacterium tuberculosis, we compared the outcome of M. tuberculosis infection in MyD88, TRIF/MyD88, IL-1R1, and IL-1β–deficient mice. All four strains displayed acute mortality with highly increased pulmonary bacterial burden suggesting a major role for IL-1β signaling in determining the MyD88 dependent phenotype. Unexpectedly, the infected MyD88 and TRIF/MyD88-deficient mice, rather than being defective in IL-1β expression, displayed increased cytokine levels relative to wild-type animals. Similarly, infected mice deficient in caspase-1 and ASC, which have critical functions in inflammasome-mediated IL-1β maturation, showed unimpaired IL-1β production and importantly, were considerably less susceptible to infection than IL-1β deficient mice. Together our findings reveal a major role for IL-1β in host resistance to M. tuberculosis and indicate that during this infection the cytokine can be generated by a mechanism that does not require TLR signaling or caspase-1.
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