Mycobacterial infection induces eosinophilia and production of α-defensin by eosinophils in mice.

It has been well known in humans that eosinophil infiltration into the site of inflammation and eosinophilia occur in mycobacterial infections. However, the role of eosinophils against the mycobacterium is unclear. We showed in previous study that in situ mouse eosinophils infiltrated into tissues produce α-defensin, an anti-bacterial peptide. We investigated in this study whether eosinophils reacting to mycobacteria produce α-defensin in mice and whether it can be used as a model. We showed that mycobacterial infection induced blood eosinophilia and infiltration of α-defensin producing eosinophils that to surround mycobacteria at the site of infection. These findings were usually seen during human mycobacterial infection. We established a good model to study host defense mechanism against mycobacteria through α-defensin via eosinophils.