Inhibition of CD8+ T lymphocytes attenuates respiratory syncytial virus-enhanced allergic inflammation.
BACKGROUND
CD8+ T cells have an important role in the pathogenesis of respiratory virus-induced asthma exacerbations. However, the cellular mechanism of CD8+ T cells, linking viral respiratory infections to the development of airway inflammation, is not well defined.


OBJECTIVE
To clarify the role of CD8+ T cells in the development of respiratory virus-induced asthma exacerbations.


METHODS
Using a murine model of prior ovalbumin exposure and subsequent respiratory syncytial virus infection, the airway responsiveness was assessed by barometric whole-body plethysmography. Airway eosinophils, lymphocytes, neutrophils as well as IFN-gamma, IL-4, IL-5 and IL-13 in bronchoalveolar lavage fluid were measured by Diff-Quick staining and ELISA. The frequency of cytokine-producing CD8+ T lymphocytes in peribronchial lymph nodes was detected using 2-color immunofluorescence analysis. Histological examinations were carried out using hematoxylin and eosin and immunohistochemistry.


RESULTS
Anti-CD8 monoclonal antibody (1 mg/kg) clearly inhibited increases in airway responsiveness to acetylcholine and markedly reduced the number of eosinophils, neutrophils, lymphocytes as well as IL-4, IL-5 and IL-13 levels in bronchoalveolar lavage fluid. Furthermore, the antibody also attenuated airway inflammation and CD8+ T lymphocyte infiltration in lung tissue.


CONCLUSIONS
These findings suggest that CD8+ T lymphocytes play a critical role for the development of respiratory syncytial virus-induced airway inflammation and airway hyperresponsiveness.
Jiang
Xiong-bin
XB
Department of Respiratory Disease, First Affiliated Hospital of Nanjing Medical University, Nanjing, PR China.
Wang
Zheng-dong
ZD
Zhu
Yi
Y
Zhang
Xi-long
XL
Cui
Xue-fan
XF
Yao
Kun
K
Yin
Kai-sheng
KS
D000818:Animals; D000911:Antibodies, Monoclonal; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D016207:Cytokines / Q000378:metabolism; D005260:Female; D054884:Host-Pathogen Interactions; D007249:Inflammation / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D020556:Neutrophil Infiltration; D012130:Respiratory Hypersensitivity / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D018357:Respiratory Syncytial Virus Infections / Q000276:immunology*; D012136:Respiratory Syncytial Viruses / Q000502:physiology; D013154:Spleen / Q000276:immunology
D000911:Antibodies, Monoclonal; D016207:Cytokines