Assay of Pertussis Vaccine Reactivity Factors by Measurement of the Paw Swelling Response, Endotoxin and Histamine-sensitizing Factor

Abstract

Abstract.Bordetella pertussis is composed of a series of active components: (1) a heat-labile or dermonecrotic toxin (HLT); (2) a lipopolysaccharide endotoxin (LPS); (3) pertussis toxin; (4) filamentous hemagglutinin (FHA); (5) agglutinogens; (6) outer membrane proteins; (7) adenylate cyclase; and (8) tracheal cytotoxin. Pertussis toxin (PT), also called lymphocytosis-promoting factor (LPF), encompasses a series of biological activities including: (1) histamine-sensitization (HSF); (2) leukocytosispromoting activity (LPF); (3) LPF-hemagglutinin (LPF-HA); and (4) pancreatic islet-activating protein (IAP). The heat-labile toxin is inactivated during vaccine production. Pertussis toxin is inactivated when heated to 80°C for 30 min and endotoxin at a temperature greater than 120°C for 30 min. The effect of pre- and post-heat treatment on DTP vaccine, Bordetella pertussis endotoxin, pertussis toxin and a pertussis toxin/endotoxin combination, was determined as related to: (1) paw swelling response; (2) LAL activity (endotoxin); and (3) HSF activity. With the exception of DTP and B. pertussis endotoxin, the average paw swelling response after injection of non-treated and heat-treated test samples was similar to the saline control at all measured time intervals, Contrary to anticipated results, heat treatment enhanced the paw-swelling response of DTP vaccine and B. pertussis endotoxin. Endotoxin levels, as measured by LAL, were significantly lower after heat-treatment, with the exception of B. pertussis endotoxin and the E-1 control. The addition of pertussis toxin, B. pertussis endotoxin or pertussis toxin/endotoxin did not restore LAL values to the levels seen for non-treated DTP vaccine. The HSF activity of vaccine, and the pertussis toxin/endotoxin was significantly lowered by heat treatment. Bordetella pertussis endotoxin showed no HSF activity either pre- or post-heat treatment.