Measurement of Antibody Affinity, Concentration and Isotype to Evaluate Antigens, Adjuvants, and Immunization Regimens in Vaccine Research

The recent explosion in vaccine research has brought into focus the need for better methods of characterizing the serum antibodies produced in animals immunized with various adjuvants and antigens. The typical end-point ELISAs used to characterize sera fail to differentiate between antibody affinity and concentration and cannot quantitate antibody isotypes. Antibody affinity and concentration when measured directly can serve as invariant standards to judge the quality of immunization and are not subject to arbitrary interpretation that is applied to end-point titer ELISAs. Furthermore, antibody affinity determines the effectiveness of antibody in j protection (reviewed in Steward and Steensgard, 1983). Antibody isotypes, which are often neglected in evaluating vaccines, have also been shown to have a marked effect on the generation of immunoprophylaxis (Wechsler and Kongshavn, 1986). We therefore suggest that measurements of antibody affinity, concentration, and isotype should be included in the evaluation of the efficacy of a vaccine. To measure these characteristics, we have developed a convenient solution-phase RIA for antibody affinity and concentration and an ELISA for antibody isotypes.