[Effects of vaccae on airway inflammation and Th1/Th2 cytokines in sensitized mice].
OBJECTIVE
To study the inhibitory effect of Mycobacterium vaccae (M. vaccae) on the accumulation of airway inflammatory cells and its regulatory effect on IFN-gamma/IL-4 balance in bronchoalveolar lavage fluids (BALF) from ovalbumin (OVA)-challenged and sensitized mice, therefore to provide experimental evidence for the application of M. vaccae in the treatment of asthma.


METHODS
Sensitized mice were given a single dose of M. vaccae 3 days before inhaled OVA-challenge by one of the three routes: intramuscularly (i.m.), by intratracheal (i.t) instillation or by cutaneous scarification (c.s). Accumulation of inflammatory cells, IFN-gamma and IL-4 levels in BALF were determined.


RESULTS
The total numbers of the inflammatory cells in BALF from the M. vaccae 2.25 micro g (per mouse) c.s group (6 +/- 6) x 10(8)/L, the 2.25 microgram i.t group (7 +/- 6) x 10(8)/L and the 22.5 micro g i.m group (8 +/- 5) x 10(8)/L, were significantly lower than that of the model control (15 +/- 8) x 10(8)/L (P < 0.05). Eosinophils in the 2.25 microgram c.s group 0.7 +/- 0.5, the 2.25 microgram i.t group 1.6 +/- 1.9, the 7.5 micro g i.m group 2.6 +/- 1.3 and the 22.5 microgram i.m group 1.40 +/- 1.20, were significantly lower than those in the model group 4.90 +/- 4.60 (P < 0.05 and P < 0.01). IFN-gamma levels in the 2.25 microgram c.s group (289 +/- 57) pg/ml, the 2.25 micro g i.t group (335 +/- 57) pg/ml and the 22.5 micro g i.m group (313 +/- 49) pg/ml, were significantly higher than that in the model group (216 +/- 42) pg/ml (P < 0.05 and P < 0.01). IL-4 levels in the 2.25 microgram c.s group (63 +/- 19) pg/ml, the 2.25 microgram i.t group (8 +/- 5) pg/ml and the 22.5 micro g i.m group (13 +/- 6) pg/ml, were significantly lower than that in the model group (93 +/- 25) pg/ml (P < 0.05 and P < 0.01). The inhibitory effect on eosinophil accumulation by i.t or c.s M. vaccae was 10 times stronger than that by i.m M. vaccae. i.t M. vaccae was the most effective in regulating the IFN-gamma/IL-4 ratio.


CONCLUSIONS
M. vaccae inhibited airway inflammation via regulating Th1/Th2 balance, suggesting that it may be beneficial in the treatment of asthma.
Xie
Qiangmin
Q
Zhejiang Respiratory Drugs Research Laboratory of State Drugs Administration of China, Medical School of Zhejiang University, Hangzhou 310031, China.
Bian
Rulian
R
Wu
Kangsong
K
Zheng
Xing
X
D000818:Animals; D001249:Asthma / Q000628:therapy*; D001428:Bacterial Vaccines / Q000627:therapeutic use*; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D004802:Eosinophilia / Q000517:prevention & control; D005260:Female; D006801:Humans; D007249:Inflammation / Q000517:prevention & control*; D007371:Interferon-gamma / Q000032:analysis; D015847:Interleukin-4 / Q000032:analysis; D008297:Male; D051379:Mice; D009161:Mycobacterium / Q000276:immunology*; D010047:Ovalbumin / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology*
D001428:Bacterial Vaccines; D015847:Interleukin-4; D007371:Interferon-gamma; D010047:Ovalbumin