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Protective Immunogenicity of Pertussis Toxin Enriched Fractions of Bordetella Pertussis Culture Supernatant.

1Wahby AF, 2El-Kady EM, and 3Osman MN.

Departments of 1Molecular Biology and 2Microbial Biotechnology, National Research Center, Cairo, Egypt and 3Bacterial Vaccines, The Egyptian Organization for Biological Products and Vaccines.

 

Culture supernatants of Bordetella pertussis (B. pertussis) strains 134 and 509 grown in a fully monitored fermentor were concentrated by ultrafiltration. Two PT enriched fractions (F3 and F4), were obtained by direct chromatography of the fresh concentrated supernatant of B. pertussis strain 134 on Sephacryl S-300. The two fractions contained high concentrations of the intact PT as judged by cytotoxicity for CHO cells and the high ELISA titers for PT. The glutaraldehyde inactivated F3 and F4 were more potent than glutaraldehyde inactivated PT in protection of mice against virulent B. pertussis as judged by vaccination challenge experiments. The relatively simple procedures for preparation of these immunogenic fractions make them good candidates for preparation of acellular vaccines. The supernatants were unstable at 4ºC, a soluble fraction and an insoluble fraction were resolved by low speed centrifugation. Whereas, highly aggregated proteins were obtained on reconstitution of the lyophilized supernatants. Immunoblots, developed with two rabbit antisera to whole cell pertussis vaccine (WCV) and the supernatant antigens revealed that the insoluble fraction contained most of the filamentous hemagglutinin (FHA), whereas the soluble fraction contained most of the pertussis toxin (PT).