Subclass distribution of rubella virus-specific immunoglobulin G

An enzyme-linked immunosorbent assay was used to study the subclass distribution of rubella virus-specific immunoglobulin G (IgG) in 97 serum samples from healthy donors and from patients with recent or remote rubella infections. Plastic beads coated with rubella antigen were incubated with test serum and then with monoclonal antibodies to the four human subclass of IgG. Rubella virus-specific IgG1 was present in all serum samples containing rubella virus-specific IgG antibodies. Rubella virus-specific IgG2 was present in 1 of 35 samples from healthy donors that also contained specific IgG1. Rubella virus-specific IgG3 was found in serum samples from patients with recent rubella infections but had disappeared by 6 months after the onset of symptoms. Rubella virus-specific IgG4 was found in low amounts in 7 of 35 samples from healthy immune donors. Of 20 serum samples that were negative by other serological techniques, 8 gave absorbances above cutoff levels in the assays for rubella virus-specific total IgG and IgG1. In 1 of 20 serum samples, the assays for total IgG and IgG2 were positive. High absorbance in the assay for rubella virus-specific IgG4 was found in one serum. This serum was negative in all other assays for rubella virus-specific antibodies.