Nod1 signaling overcomes resistance of S. pneumoniae to opsonophagocytic killing
2007

Nod1 Signaling Helps Kill Streptococcus pneumoniae

Sample size: 10 publication 10 minutes Evidence: high

Author Information

Author(s): Lysenko Elena S, Clarke Thomas B, Shchepetov Mikhail, Ratner Adam J, Roper David I, Dawson Christopher G, Weiser Jeffrey N

Primary Institution: University of Pennsylvania School of Medicine

Hypothesis

Does Nod1 signaling enhance the ability of neutrophils to kill Streptococcus pneumoniae during co-colonization with Haemophilus influenzae?

Conclusion

Nod1 signaling is crucial for neutrophils to effectively kill Streptococcus pneumoniae when co-colonized with Haemophilus influenzae.

Supporting Evidence

  • Neutrophils from mice treated with Haemophilus influenzae showed increased killing of Streptococcus pneumoniae.
  • Nod1−/− mice had reduced clearance of Streptococcus pneumoniae during co-colonization.
  • Peptidoglycan from Haemophilus influenzae was identified as the stimulus for enhanced neutrophil activity.
  • Neutrophil-mediated killing required complement opsonization.
  • Products from Haemophilus influenzae enhanced neutrophil activity independently of TLR2 and TLR4.

Takeaway

When two types of bacteria are in the same place, one can help the body's immune cells get rid of the other. This study shows that a special signal called Nod1 helps white blood cells kill a harmful bacteria called Streptococcus pneumoniae.

Methodology

The study used a murine model to examine the effects of Haemophilus influenzae on the neutrophil-mediated killing of Streptococcus pneumoniae.

Limitations

The study primarily used a mouse model, which may not fully replicate human responses.

Participant Demographics

Mice used included C57Bl/6 and Nod1−/− strains.

Statistical Information

P-Value

p<0.01

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1371/journal.ppat.0030118

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