a key bactrial protein that can serve as a vaccine

What is it about?

The Burkholderia cepacia complex (Bcc) is a group of Gram‐negative opportunistic pathogens causing infections in people with cystic fibrosis (CF). Bcc is highly antibiotic resistant, making conventional antibiotic treatment problematic. The identification of novel targets for anti‐ virulence therapies should improve therapeutic options for infected CF patients. We previously identified that the peptidoglycan‐associated lipoprotein (Pal) was immunogenic in Bcc infected CF patients; however, its role in Bcc pathogenesis is unknown. The virulence of a pal deletion mutant (Δpal) in the insect infection model Galleria mellonella was highly reduced (88-fold) compared to wild type. Δpal was also more susceptible to polymyxin B. Structural elucidation by X‐ray crystallography and calorimetry demonstrated that Pal binds peptidoglycan fragments. Δpal showed reduced stimulation of the neutrophil recruiting chemokine IL‐8 in CF epithelial cells relative to wild type, demonstrating that Pal is a significant driver of inflammation. The Δpal mutant had reduced binding to CFBE41o− cells, but adhesion of Pal‐expressing recombinant E. coli to CFBE41o− cells was enhanced compared to wild‐type E. coli (p < .0001), confirming that Pal plays a direct role in host cell attachment. Overall, Bcc Pal mediates host cell attachment and stimulation of cytokine secretion, contributing to Bcc pathogenesis.

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Why is it important?

This work should the importance of the Pal protein in Burkholderia cenocepacia infection and also reveals many unexpected features of this protein in the bacterial physiology