Effect of Mycobacterium tuberculosis chaperonins on bronchial eosinophilia and hyper-responsiveness in a murine model of allergic inflammation.
BACKGROUND
Epidemiological evidence suggests that infection with Mycobacterium tuberculosis protects children against asthma. Several laboratories have shown that, in mouse models of allergic inflammation, administration of the whole live tuberculosis vaccine, Mycobacterium bovis bacillus Calmette-Guerin (BCG), prevents ovalbumin (OVA)-induced pulmonary eosinophilia.


OBJECTIVE
The aim of this study was to characterize specific M. tuberculosis molecules that are known to modulate immune responses to see if they affected pulmonary eosinophilia and bronchial hyper-responsiveness.


METHODS
C57Bl/6 mice were sensitized to OVA on days 0 and 7 and subsequently challenged with OVA on day 14 over a 3-day period. Pulmonary eosinophilia and bronchial hyper-responsiveness were measured 24 h following the last antigen challenge. In some groups, mice were pre-treated with M. tuberculosis or M. tuberculosis chaperonins (Cpns)60.1, 60.2 and 10, and the effect of this treatment on the allergic inflammatory response to aerosolized OVA was established.


RESULTS
We show that M. tuberculosis Cpns inhibit allergen-induced pulmonary eosinophilia in the mouse. Of the three Cpns produced by M. tuberculosis, Cpn60.1, Cpn10 and Cpn60.2, the first two are effective in preventing eosinophilia when administered by the intra-tracheal route. Furthermore, the increase in airways sensitivity to inhaled methacholine following OVA challenge of immunized mice was suppressed following treatment with Cpn60.1. The allergic inflammatory response was also characterized by an increase in Th2 cytokines IL-4 and IL-5 in bronchoalveolar lavage fluid, which was also suppressed following treatment with Cpn60.1.


CONCLUSIONS
These data show that bacterial Cpns can suppress eosinophil recruitment and bronchial hyper-responsiveness in a murine model of allergic inflammation.
Riffo-Vasquez
Y
Y
Sackler Institute of Pulmonary Pharmacology, GKT School of Biomedical Science and Medicine, King's College London, London, UK.
Spina
D
D
Page
C
C
Tormay
P
P
Singh
M
M
Henderson
B
B
Coates
A
A
D000818:Animals; D001249:Asthma / Q000188:drug therapy / Q000276:immunology* / Q000503:physiopathology; D001980:Bronchi / Q000187:drug effects / Q000276:immunology*; D001985:Bronchial Provocation Tests; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D018835:Chaperonin 10 / Q000627:therapeutic use; D018834:Chaperonin 60 / Q000627:therapeutic use; D018833:Chaperonins / Q000378:metabolism*; D004804:Eosinophils / Q000276:immunology*; D006967:Hypersensitivity / Q000188:drug therapy / Q000276:immunology / Q000503:physiopathology; D007167:Immunotherapy; D008168:Lung / Q000187:drug effects / Q000276:immunology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D023421:Models, Animal; D009163:Mycobacterium bovis / Q000276:immunology; D009169:Mycobacterium tuberculosis / Q000378:metabolism*; D011994:Recombinant Proteins / Q000008:administration & dosage; D015656:Respiratory Mechanics
D018835:Chaperonin 10; D018834:Chaperonin 60; D011994:Recombinant Proteins; D018833:Chaperonins