[Effects and mechanism of CD4+ CD25+ T cells on the airway inflammation of asthmatic mice].
OBJECTIVE
To investigate the effects and mechanism of CD(4)(+) CD(25)(+) T cells on the airway inflammation of asthmatic mice.


METHODS
Sixty mice were divided into 3 groups (20 in each group) including group A [ovalbumin (OVA) sensitized/challenged mice], group B (saline sensitized/challenged mice), group C [CD(25)(+) T cells deleted by anti-CD(25)(+) and OVA sensitized/challenged mice]. Mice of A group were sensitized on days 1 and 13 by OVA and challenged from days 21 to 29 by 2% OVA 10 ml repeatedly to establish a murine model of asthma characterized by airway inflammation. The mice of group B were treated by saline 10 ml. The mice of group C were treated by the same method of group A after deletion of the CD(25)(+) T cells by anti-mouse CD(25)(+) monoclonal antibody (McAb). Lymphocytes were separated from the spleen of the three groups and the number of T cells were calculated by Fluorescence Activated Cell Sorter (FACS). The CD(4)(+) T cells were purified and the expression of interleukin-10 (IL-10), transforming growth factor-beta(1) (TGF-beta(1)) and cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) mRNA were analyzed by the method of reverse transcriptase-polymerase chain reaction (RT-PCR). The airway inflammatory indices were detected by hematoxylin and eosin (HE) staining.


RESULTS
In repeatedly OVA-challenged mice (group A), the ratio of CD(4)(+) CD(25)(+) T cells to CD(4)(+) T cells decreased significantly [(3.10 +/- 0.03)%] as compared with group B [(9.60 +/- 0.04)%, P < 0.01]. The expression of IL-10, CTLA-4 mRNA and TGF-beta(1) mRNA of OVA-challenged mice (group A) decreased significantly (0.250 +/- 0.040 vs 0.29 +/- 0.03, 0.28 +/- 0.06 vs 0.480 +/- 0.080, 0.47 +/- 0.05 vs 0.50 +/- 0.03, all P < 0.01). The expression of IL-10, CTLA-4 mRNA and TGF-beta(1) mRNA of the mice treated by anti-CD(25)(+) McAb (group C) decreased as compared with groups A and B (0.080 +/- 0.020, 0.11 +/- 0.04, 0.12 +/- 0.05, P < 0.01). The inflammation in the lungs of mice with depleted CD(4)(+) CD(25)(+) T cells by anti-CD(25)(+) McAb was more marked than that in the OVA-challenged and control group mice.


CONCLUSIONS
The polarization of CD(4)(+) CD(25)(+) T cells in asthmatic mice decreased significantly, which may play an important role in the pathogenesis of asthma.
Sun
Kun
K
Institute of Respiratory Disease, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
Lin
Ke-xiong
KX
Wu
Kui
K
Wang
Chang-zheng
CZ