[Microtiter enzyme-linked immunosorbent assay for rubella antibodies in human sera--analysis by parallel line assay method].

Antibodies against rubella virus in human sera were measured by ELISA and antibody titers were calculated by the parallel line assay method. The dose response regression curves of standard sera and test sera containing IgG antibody calculated by the parallel line assay method showed linearity, and were parallel to one another. However, the regression lines of sera positive for IgM antibody against rubella virus were not parallel to one another in the low dilution region, but parallel in the higher dilution region. A good correlation was observed between the rubella IgG antibody titers measured by the hemagglutination-inhibition (HI) test and those calculated by the parallel line assay method. The coefficient of the correlation was 0.781. Time-course studies of IgG or IgM antibody titers against rubella virus in rubella patients or in vaccines with MMR vaccine indicated that the ELISA was more precise and specific method than the HI test. Thus, the parallel line assay method using ELISA is considered to be a more useful method for the detection and quantification of antibodies to rubella than the conventional HI test.