Enzyme and radioimmunoassays for specific murine IgE and IgG with different solid-phase immunosorbents.

Enzyme and radioimmunoassays of specific murine IgE and IgG were done using antigen-coated flex vinyl plates, antigen-coupled paper discs or Sepharose 4B beads as solid-phase immunosorbents. These 3 immunosorbents differ in their antibody binding capacities. Only Sepharose beads have a high capacity so that they can be used to assay specific IgE in serum samples without interference from specific IgG which can be present in concentrations of several thousand times greater than those of specific IgE. All 3 types of immunosorbents are equally useful for assaying specific IgG, but the flex vinyl plate is the immunosorbent of choice since it requires less time and gives lower blanks than do the other two. Under the conditions tried, the lowest detectable concentration of specific IgE or IgG was about 1 ng/ml on enzyme or radioimmunoassay. The immunoassays described in this paper are useful for following the kinetics of specific IgE and IgG responses in mice. This was demonstrated with sera from mice immunized with ragweed antigen E.