Immune Electron Microscopy for Virus Detection

The complete method used for immune electron microscopy is described by Horvatits et al. [24 (link)]. Briefly, 10 µL of each of the samples was adsorbed onto carbon/formvar -oated copper grids (Plano GmbH, Wetzlar, Germany) and contrasted with 2% uranyl acetate. Detergent treatment was performed before adsorption with 0.1% sodium deoxycholate (Na-DOC) for 10 min at 4 °C as described [25 (link)], to either remove the quasi envelope or to eliminate the virus-like particles of hepatitis B virus surface antigen. For immune-detection, an HEV capsid protein-specific monoclonal antibody [26 (link)] was used together with a gold-labeled secondary antibody. The samples were examined using a JEM 1400 transmission electron microscope (JEOL GmbH, Freising, Germany) operated at 120 kV. Imaging was performed using a Veleta G2 camera (EMSIS GmbH, Münster, Germany). Particles size measurement was done using ITEM software (Olympus, Hamburg, Germany).