Human parvovirus B19: ELISA and immunoblot assays

An ELISA for the detection of specific IgM and IgG against human parvovirus B19 (anti-B19 IgM and IgG) and B19 antigen is described. With ELISA anti-B19 IgM could be detected for up to 20 weeks after viraemia. Four to five months after B19 infection anti-B19 IgG titres range between 10(-6) and 10(-7). Nonspecific reactions with rheumatoid factor or IgM against rubella were not found. The ELISA for B19 antigen was shown to be as sensitive as DNA hybridisation. With immunoblotting two viral proteins of 83 kd (VP1) and 58 kd (VP2) were demonstrated. After acute infection antibodies to VP2 appear before antibodies to VP1. Immunoblotting might be used in pregnancy to determine the time of maternal infection. In a survey of a B19 outbreak in a school for medical technology, 6 (28.6%) of 21 non-immune females seroconverted.