[The issues in detection of avian-type receptors for influenza viruses]

Influenza viruses utilize sialic acid-containing glycoconjugates as receptors. The distribution of receptors in host tissues has been investigated in many species to understand the ecology of influenza viruses in nature and the mechanisms of interspecies transmission of the viruses. On the other hand, lectins, which have been widely used to detect these receptor molecules, have many different characteristics from antibodies and thus, require special attention in interpreting the results of lectin staining. In particular, lectins derived from Maackia amurensis, which has been used to detect Siaα2-3Gal, the avian-type receptor for influenza viruses, have been used without fully understanding its characteristics. This led to some confusion in interpreting the distribution of influenza virus receptors in host tissues. How accurately do we know the distribution of avian-type receptors in host animals? In this article, we would like to suggest reviewing the influenza virus receptors by providing issues related to Maackia lectins.