Fluorescence labeling of human rhinovirus capsid and analysis by capillary electrophoresis

The capsid of human rhinovirus serotype 2, consisting of four viral proteins, was fluorescence-labeled with fluorescein isothiocyanate and analyzed by capillary electrophoresis using UV and laser-induced fluorescence detection. Heat denaturation, proteolytic digestion, and receptor binding were applied for confirmation of the identity of the peak with the labeled virus. Incomplete derivatization with the fluorophore preserved the affinity of the virus for its receptor, indicating that its cell entry pathway is unperturbed by this chemical modification; indeed, an infectivity assay confirms that the labeled virus samples are infectious. The results show that fluorescence labeling of the viral capsid might lead to a valuable probe for studying infection processes in the living cell.