Rubella IgM and IgG Following Rubella Vaccination in Humans and Baboons Measured by Enzyme Linked Immunosorbent Assays ([LISA)

Abstract

Vaccination represents one of the lowest levels of antigen stimulation that will induce protective antibody. An assay would require high sensitivity to detect the minimal response of a vaccine. Nine humans were vaccinated with rubella RA-27 vaccine and three baboons were inoculated with purified HPV-77 rubella vaccine. The development of rubella antibody in serial post-vaccination samples was monitored by enzyme linked immunosorbent assays (ELISA) designed to detect human IgM and IgG to rubella and a hemagglutination inhibition (HAI) test. Positive levels of rubella specific IgM were measured from 14 to 42 days post-vaccination. Positive levels of rubella specific IgG were not measured until after 28 days in all but one vaccine. Peak rubella specific IgM and final rubella specific IgG levels were lower than observed for natural rubella infection. HAI titers were positive after three weeks. Baboon rubella specific IgM values were elevated over pre vaccination values between day 9 and day 27. Rubella specific IgG values were elevated continuously after day 11. HAI values were positive after day 9. Although elevated, neither the baboon rubella specific IgG or IgM ELISA values reached a level equivalent to that seen in humans post-vaccination. HAI titers indicated the baboons responded to vaccination. Revaccination of two baboons failed to increase antibody levels detected either by ELISA or HAI. ELISA binding and competition studies demonstrated that anti-human IgM and IgG conjugates had decreased reactivity with baboon globulin compared to human globulin. With new interpretation ranges based on the relative reactivity of baboon globulin to human globulin the baboons antibody response was comparable to human response to rubella vaccination. ELISA demonstrated the sensitivity and specificity for determining both the IgM and IgG response following rubella vaccination.