Objectives: a) To develop new assays with the goal of defining a serologic correlate of clinical protection. b) To work toward the international standardization of ELISA's used to evaluate the antigen and isotype specific responses to B. pertussis. c) to employ these assays to evaluate the serologic response in individuals either vaccinated with pertussis vaccine or infected with B. pertussis. FY93 activities: 1. Worked with 3 university laboratories and 2 foreign laboratories to transfer the standardized assay so that these laboratories could use the assays to evaluate the serologic response in clinical trials. Performed validation tests on reagents and approximately 500 ELISA tests to assess interlaboratory reproducibility. 2. Initiated the performance about 2000 ELISA tests on a sub-group of individuals from an NIAID study who received licensed whole cell pertussis vaccine as a primary and one of the 13 different acellular vaccines as a fourth dose. 3. Applied the standardized methodology to sera from Japanese and American children immunized with Japanese acellular pertussis vaccines in order to compare the antibody response in these two populations. 4. Demonstrated by ELISA and immunoblotting that both vaccinated and infected individuals develop an antibody response to the B-oligomer of pertussis toxin that correlates well with the response to holotoxin. 5. Evaluated the sera from immunized mice for opsonic activity. 6. Prepared rabbit polyclonal antisera to PT, FHA, pertactin, fimbriae, and LOS that are being used as reagents in immunoassay systems.