Mast cells impact the acute innate immune response to RSV by reducing viral load and promoting eosinophil recruitment 2952

Abstract Description Respiratory viral infections, including Respiratory Syncytial Virus (RSV) are major health threats. Mast cells are resident innate immune effector cells which produce multiple mediators in response to viral infections. This study determined the role of mast cells in responses to early RSV infection. Mast cell-deficient Cpa3-Cre; Mcl-1fl/fl mice exhibited significantly higher viral loads, greater weight loss, and more tissue damage compared to wild type mice two days post infection. This was associated with increased inflammatory monocyte influx and elevated immune mediators CXCL10, CCL4 and TNF in the lung following RSV infection. Mast cell deficiency was also associated with reduced and phenotypically distinct eosinophil populations in lung tissue in the absence of infection. Mice selectively reconstituted with mast cells exhibited similar lung eosinophil populations and responses to RSV as wild types. These studies reveal the protective role of mast cells during RSV infection, offering valuable insight to enhance future treatment strategies. Funding Sources This work was funded by CIHR (grant no. MOP10966 and PJT 173350) to JSM, with additional support from the Dalhousie Medical Research Foundation (DMRF) and an American Association for Immunology fellowship awarded to RHN. Topic Categories Immune Response Regulation: Cellular Mechanisms (IRC)