Use of immune electron microscopy to investigate antigenic relationships of virsuses: studies with arboviruses and hepatitis B antigens

Representatives of five arbovirus taxons (alphavirus, flavivirus, bunyavirus, rhabdovirus and orbivirus) and Hepatitis B core antigen were studied by immune electron microscopy (IEM) in an attempt to determine the suitability of IEM for the study of antigenic relationships among viruses, for rapid identification of virus unknowns and for antibody detection. Arbovirus antigens were used to titrate hyperimmune mouse ascitic fluids and guinea pig sera. With the exception of the orbiviruses, specific clumping was observed for all homologous systems studied. Studies by IEM confirmed the antigenic relationships between arboviruses which had previously been demonstrated by other serological tests. Alphavirus unknowns were identified in the IEM test by the use of appropriate dilutions of antisera. The Hepatitis B core antigen was used in the IEM test to detect core antibody in sera from patients with hepatitis B infections. In the same test, the core antigen did not show any cross-relationship with Hepatitis B surface antigen