VACCINATION OF NEWBORN MICE WITH BACILLE CALMETTE-GUERIN (BCG) SHOWS LONG TERM INHIBITORY EFFECT ON AIRWAY EOSINOPHILIC INFLAMMATION INDUCED BY OVALBUMIN (OVA) AND RAGWEED EXPOSURE

Yang J, Wang S, Fan Y, Bilenki L, Han X, Yang X

Departments of Medical Microbiology and Immunology, University of Manitoba, Winnipeg, Manitoba, Canada

 

Objective: We have reported previously that intravenous infection with BCG can inhibit de novo and established allergic responses induced by OVA in adult mice. The present study examined the effect of early exposure to mycobacterial infection on the development of allergic responses induced by OVA and a natural allergen, ragweed.

Methods: Newborn female C57BL/6 mice were vaccinated with Mycobacterium bovis BCG via intraperitoneally (i.p.) or subcutaneously  (s.c.) Injection at 6-7 days of age, sensitized with OVA or ragweed (1-2 ¦Ìg in alum) at 6-8 weeks old and challenged intranasally with the same allergen (25-50 ¦Ìg) at 2 weeks after sensitization. Mice were sacrificed at various days allergen challenge and examined for antibody response, airway inflammation and cytokine production.

Results: Vaccination with BCG by i.p or s.c. route significantly inhibited airway eosinophilia induced by intranasal challenge with OVA or ragweed, which was correlated with significant reduction in airway expression of vascular cell adhesion molecule (VCAM)-1. Boost vaccination at 2-4 weeks following primary immunization failed to enhance the inhibitory effect. Cytokine analysis showed significant increase in allergen driven IFN¦Ã and IL-12 production by spleen and lymph node cells without significant change in IL-4, IL-5 and IL-13 production. Serum IgE levels appears comparable between the groups of mice with or without early stage BCG vaccination.

Conclusion: Early exposure to mycobacterial infection may have a long-term inhibitory effect on subsequent asthma-like reaction especially airway eosinophilia induced by natural allergen.

 

 
0413