Specific identification of human cytomegalovirus isolates by anti-complement immunofluorescence with immune hamster sera

Anti-complement immunofluorescence establishes nuclear localization of human cytomegalovirus matrix protein

A monospecific, polyclonal antiserum to the 69-kDa matrix protein of human cytomegalovirus (HCMV) was prepared in a guinea pig and used to determine the intracellular distribution of this viral antigen. The resulting antiserum was specific for infected cells as tested by immunofluorescence, and specific for the HCMV matrix protein as determined by "nitrocellulose immunoassay" of electrophoretically separated, infected-cell proteins. Antibodies were reacted with fixed, infected human fibroblasts, and visualized by the anti-complement immunofluorescence procedure to avoid complications arising from the strong IgG Fc binding activity of the infected-cell-specific cytoplasmic inclusion. Results establish that the matrix protein is located in the nucleus, and indicate that it is concentrated in the nucleoplasm rather than within the intranuclear inclusions.

An interchangeable ELISA for cytomegalovirus antigen and antibody

An enzyme-linked immunosorbent assay (ELISA) was developed to demonstrate cytomegalovirus (CMV) antibodies and antigen. A nuclear antigen from CMV-infected cells was used for detection of IgG and IgM antibodies. Significant rises of CMV-IgG and significant levels of CMV-IgM were found in sera from patients with acute CMV only, and not with other herpesvirus infections. CMV antigens were demonstrated in cells and in culture medium by a sandwich or by an inhibition ELISA technique. In the sandwich technique, the plates were coated with monkey anti-CMV IgG and rabbit anti-CMV IgG was used as the second antibody. Both early and late CMV antigens were identified with this method. Treatment of CMV containing samples using freeze--thawing or detergent reduced the infectivity, but the antigenicity was not affected. There was no cross-reactivity with herpes simplex or varicella-zoster virus.