Development and Duration of Mumps Fluorescent Antibodies in Various Immunoglobulin Fractions of Human Serum

Abstract

Abstract The indirect immunofluorescence technique was successfully adapted to the detection and titration of mumps virus antibodies in human sera. The curve of antibody development and duration for 3 months following the onset of clinical disease was measured with fluorescein-labeled antisera prepared against the IgG, IgA and IgM fractions as well as the whole human GG, and was compared with neutralizing antibodies. Antibodies in the whole GG and the IgG fraction were present in high titer at the time of onset and persisted unchanged for at least 3 months. IgM antibodies also developed rapidly to somewhat lower titers but declined steadily and were rarely detectable 50 days after the disease. Limited observations on the curve of IgA antibodies indicated that they too are transient and decline during the first month after infection. Neutralizing antibodies in these same individuals developed slowly and to relatively lower titers but persisted for the duration of the study. The specificity of reactions with labeled antisera for various fractions of GG was confirmed by treatment with 2-ME followed by density gradient centrifugation. The FA response of individuals receiving live, attenuated mumps virus vaccine was measured using conjugates prepared against IgM and whole GG and was found to correspond closely to that measured by the neutralization technique. The extent of subclinical infection and immunity among 48 ward contacts of cases in an institution was determined by testing paired serum specimens which had been collected at an interval of 36 days. Thirty-one per cent were found to be serologically immune. Twenty-five per cent remained susceptible and 43% experienced subclinical infection. Reactions between antibodies in sera of patients convalescent from mumps and antigens prepared with parainfluenza viruses of types 1, 2 and 3 were prominent with fluorescein-labeled antisera against whole GG but were completely eliminated when anti-IgM serum was employed. This rapid and highly specific diagnostic procedure has the added significance that a positive reaction in even a single serum specimen proves that the individual has experienced infection during the past few weeks.