Acinetobacter baumannii is a common cause of hospital-acquired infections in patients with impaired immune responses, and the pathogen is becoming increasingly resistant to all available antibiotics. Relatively little is known about the innate immune responses that appear to protect healthy individuals against A. baumannii infection.
Eric Skaar, Ph.D., and colleagues examined a role for the receptor TLR9 – a type of receptor that detects pathogens and alerts the immune system to infection – in response to A. baumannii infection. In mouse models of A. baumannii pneumonia and systemic infection, mice missing TLR9 had increased bacterial burdens in the lungs, more severe lung pathology and decreased pro-inflammatory factor production, compared to control mice.
The findings, reported in the October issue of Infection and Immunity, demonstrate that TLR9 contributes to the innate defense against A. baumannii disease. Understanding factors that help detect and defend against pathogens may lead to therapeutic approaches that promote an effective immune response to treat infections caused by drug-resistant pathogens like A. baumannii.
This research was supported by a Department of Veterans Affairs Merit Award and by National Institutes of Health grants DK058587, CA077955, CA116087, HL087738. Eric Skaar is a Burroughs Wellcome Fellow in the Pathogenesis of Infectious Diseases.
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