A novel immune regulatory function of neutrophils in rhinovirus infections

Rationale: Rhinovirus (RV) is a major precipitant of asthma exacerbations. During lung infections there is elevated neutrophilic inflammation which is associated with more severe asthma symptoms. Previously, we found that neutrophils respond to viral mimetics but not live RV. Here we investigated if neutrophils are activated or have other functions when co-cultured with RV-infected monocytes. Methods: Primary autologous human neutrophils and monocytes were co-cultured +/-RV16 or LPS, in either direct contact or separated by transwells (n=5-13). RV16 or LPS stimulated monocytes were exposed to killed neutrophils, neutrophil membrane or soluble neutrophil intracellular components (n=4-6). IL-6 and CXCL8 mRNA and proteins were measured by qPCR and ELISA at 24h (n=4-7). Results: Constitutive release of monocyte derived IL-6 and CXCL8 was inhibited in the presence of live neutrophils (