Pulmonary immune cells and inflammatory cytokine dysregulation are associated with mortality of IL-1R1-/-mice infected with influenza virus (H1N1)

• Main Authors: Lei Guo, Yan-Cui Wang, Jun-Jie Mei, Ruo-Tong Ning, Jing-Jing Wang, Jia-Qi Li, Xi Wang, Hui-Wen Zheng, Hai-Tao Fan, Long-Ding Liu
• Format: Article
• Language: English
• Published: Science Press, PR China 2017-05-01
• Series: Zoological Research
• Subjects: Influenza; Lung inflammation; IL-1 receptor 1; Neutrophil
• Online Access: http://www.zoores.ac.cn/EN/abstract/abstract3816.shtml

Respirovirus infection can cause viral pneumonia and acute lung injury (ALI). The interleukin-1 (IL-1) family consists of proinflammatory cytokines that play essential roles in regulating immune and inflammatory responses in vivo. IL-1 signaling is associated with protection against respiratory influenza virus infection by mediation of the pulmonary anti-viral immune response and inflammation. We analyzed the infiltration lung immune leukocytes and cytokines that contribute to inflammatory lung pathology and mortality of fatal H1N1 virus-infected IL-1 receptor 1 (IL-1R1) deficient mice. Results showed that early innate immune cells and cytokine/chemokine dysregulation were observed with significantly decreased neutrophil infiltration and IL-6, TNF-α, G-CSF, KC, and MIP-2 cytokine levels in the bronchoalveolar lavage fluid of infected IL-1R1-/- mice in comparison with that of wild type infected mice. The adaptive immune response against the H1N1 virus in IL-1R1-/- mice was impaired with downregulated anti-viral Th1 cell, CD8+ cell, and antibody functions, which contributes to attenuated viral clearance. Histological analysis revealed reduced lung inflammation during early infection but severe lung pathology in late infection in IL-1R1-/- mice compared with that in WT infected mice. Moreover, the infected IL-1R1-/- mice showed markedly reduced neutrophil generation in bone marrow and neutrophil recruitment to the inflamed lung. Together, these results suggest that IL-1 signaling is associated with pulmonary anti-influenza immune response and inflammatory lung injury, particularly via the influence on neutrophil mobilization and inflammatory cytokine/chemokine production