Age predicts cytokine kinetics and innate immune cell activation following intranasal delivery of IFNγ and GM-CSF in a mouse model of RSV infection. (September 2017) - Eichinger, Katherine M.
Highlights: Adult mice clear pulmonary cytokines faster than infant mice. IFNγ, but not GM-CSF, enhances RSV clearance from the infant murine airway. Intranasal IFNγ and GM-CSF achieve higher levels in adult vs infant airways. Low levels of IFNγ and GM-CSF are detected in the blood after intranasal delivery. Cytokine blood levels are delayed in infant vs. adult mice after pulmonary delivery. Abstract: Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infections in young children and is further associated with increased healthcare utilization and cost of care in the first years of life. Severe RSV disease during infancy has also been linked to the later development of allergic asthma, yet there remains no licensed RSV vaccine or effective treatment. Pre-clinical and clinical studies have shown that disease severity and development of allergic asthma are associated with differences in cytokine production. As a result, stimulation of the innate host immune response with immune potentiators is gaining attention for their prospective application in populations with limited immune responses to antigenic stimuli or against pathogens for which vaccines do not exist. Specifically, macrophage-activating cytokines such as interferon gamma (IFNγ) and granulocyte colony-stimulating factor (GM-CSF) are commercially available immune potentiators used to prevent infections in patients with chronic granulomatous disease and febrile neutropenia, respectively. Moreover, an increasing number of reports describe the protective function of IFNγ and GM-CSF as vaccine adjuvants. Although a positive correlation between cytokine production and age has previously been reported, little is known about age-dependent cytokine metabolism or immune activating responses in infant compared to adult lungs. Here we use a non-compartmental pharmacokinetic model in naïve and RSV-infected infant and adult BALB/c mice to determine the effect of age on IFNγ and GM-CSF elimination and innate cell activation following intranasal delivery.