Accumulating evidence suggests a potential link between influenza A virus
infection and the occurrence of
influenza-associated
neurological disorders. As
influenza infection is mediated by specific receptors on the host cell surface, it is important to understand the distribution patterns of
influenza receptors in target organs. We carried out comprehensive experiments to localize
influenza receptors in the brains of two different mouse strains and the human brain for comparison using
lectin histochemistry. We further compared the brain regions in which
influenza receptors were expressed and the regions in which experimental
influenza infection was observed. Our results show that the expression patterns for
influenza receptors in mouse and human brains are different. In the mouse brain,
human influenza virus receptors (HuIV-R) were expressed in part of brainstem and cerebellar white matter while
avian influenza virus receptors (AIV-R) were expressed in the cerebellar Purkinje neurons. In contrast, in the human brain, many neurons and glia in widespread regions, including the cerebral cortex, hippocampus, brainstem, and cerebellum, express both AIV-R and HuIV-R. Importantly, vascular endothelial cells, choroid plexus epithelial cells and ependymal cells in both mouse and human brains express high levels of HuIV-R and AIV-R. The regional reciprocity was not observed when comparing regions with
influenza receptor expression and the regions of
influenza infection within the mouse brain. Our results demonstrate a differential
influenza receptor expression pattern in mouse and human brains, and a disparity between
influenza receptor distribution and regions with actual
influenza infection.