A Detrimental Role for IL‐10 During Host Immune Responses to Influenza Virus Infection

Abstract

IL‐10 is an important anti‐inflammatory molecule that can cause immunosuppression, leading to long‐term viral persistence during chronic infection of mice with viruses such as lymphocytic choriomeningitis virus. However, its specific role during acute viral infections has not been documented. We now report that IL‐10 appears to also play a detrimental role during host responses to acute influenza virus infection since absence of IL‐10 led to improved viral clearance, weight recovery and survival rate in influenza‐infected mice. There were similar levels of CD4+ and CD8+ T cell recruitment into the lungs of infected WT and IL‐10−/− mice, and depletion of CD8+ T cells did not significantly influence viral clearance in IL‐10−/− mice. Although viral infected IL‐10−/− mice exhibited different kinetics of neutrophil recruitment compared to WT mice, neutrophil depletion did not hamper viral clearance. On the other hand, H1N1‐specific antibody levels in BALF were slightly increased in viral infected IL‐10−/− mice compared to WT mice. The mechanism of IL‐10 mediated suppression of host recovery from influenza virus infection is under further investigation. (Supported by NIH grant RO1 AI 41715)