Protein Histochemistry Using Coronaviral Spike Proteins: Studying Binding Profiles and Sialic Acid Requirements for Attachment to Tissues

Protein histochemistry is a tissue-based technique that enables the analysis of viral attachment patterns as well as the identification of specific viral and host determinants involved in the first step in the infection of a host cell by a virus. Applying recombinantly expressed spike proteins of infectious bronchitis virus onto formalin-fixed tissues allows us to profile the binding characteristics of these viral attachment proteins to tissues of various avian species. In particular, sialic acid-mediated tissue binding of spike proteins can be analyzed by pretreating tissues with various neuraminidases or by blocking the binding of the viral proteins with specific lectins. Our assay is particularly convenient to elucidate critical virus–host interactions for viruses for which infection models are limited.