Objectives: a) To prepare and maintain standard materials for the control testing of pertussis vaccines. b) To standardize the toxicity and immunogenicity tests employed for currently licensed acellular pertussis vaccines. c) To develop and evaluate new tests to assess the safety, purity, and potency of acellular pertussis vaccines. FY93 activities: 1. Evaluated alternate methods for the lyophilization of pertussis vaccines, and prepared about 2000 ampoules of a pertussis vaccine that is being evaluated as a new US Standard. 2. Organized a collaborative study to assess that potency and reproducibility of the proposed new US Standard. 3. Prepared about 500 ml of mouse serum with high titers to PT, FHA, pertactin, and fimbriae that is being evaluated as a mouse reference serum for the mouse immunogenicity test for licensed acellular vaccines and continued collaborative studies to assess the inter- laboratory reproducibility of a proposed standard assay. 4. Continued development of software for randomization and for probit and Wilson- Worcester analysis of bioassay data. 5. Applied a battery of tests that characterize acellular pertussis vaccines with respect to purity, toxicity, reversion, and immunogenicity to five lots of vaccines that are being evaluated in efficacy trials in Sweden and Italy. 6. Evaluated the characteristics of several mouse strains in the histamine sensitivity test. 7. Evaluated native and formalin-treated pertactin in a variety of electrophoretic and immunologic assays to define assays which assess the protective capacity of the molecule.