Immunity surveillance of mumps and rubella : improved methods for the detection of virus-specific antibody
The aim of these studies was to improve laboratory methods for the detection of virus-specific antibody to mumps and rubella. The presence of virus-specific antibody is indicative of immunity to disease so simple and effective antibody detection allows for the planning and monitoring of immunisation programmes. In facilitating antibody surveillance, oral fluid has advantages as a sample compared with blood. It is simple, safe and cheap to collect and being non-invasive encourages subject recruitment. In this study, an ‘IgG’ antibody capture enzyme-linked immunosorbent assay (GACELISA) was developed and evaluated for the detection of mump-specific IgG in oral fluid. Compared to an indirect commercial ELISA for the detection of mumps-specific IgG in serum, the oral fluid GACELISA was 100% sensitive and specific. The GACELISA should therefore be useful for future antibody prevalence studies. The limitation of oral fluid samples compared with blood are that they contain lower antibody concentrations. Immuno-polymerase chain reaction (I-PCR) is an ultrasensitive method and in this study was adapted to detect antibodies to mumps virus. Though the method was shown to be feasible for antibody detection and quantification, its sensitivity and specificity did not exceed that of a conventional ELISA. Sensitivity was limited by non-specific binding of human IgG to the solid phase. In this study, the PinPointTM Xa-1 T-Vector system was used to produce recombinant rubella virus (RV) E1 fusion proteins in Escherichia coli. Their antigenicity was assessed by Western blotting and ELISA. One of these antigens may be a suitable reagent for immunity studies as it reacted with RV E1-specific monoclonal antibodies (MAb’s) and a high percentage (80%) of RV antibody positive sera.