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.