All animal experiments were performed in strict accordance with all provisions of the Animal Welfare Act, the Guide for the Care and Use of Laboratory Animals, and the PHS Policy on Humane Care and Use of Laboratory Animals. The protocol was approved by the Cleveland Clinic Institutional Animal Care and Use Committee (IACUC), PHS Assurance number A3047-01. All experimental manipulations or intranasal instillations of mice were performed under anesthesia induced by pentobarbital sodium or isofluorane, respectively, and all efforts were made to minimize suffering.