Improved protocols for histamine sensitization testing of acellular pertussis vaccines

► Protocols of the histamine sensitization test (HIST) for measuring PTx in acellular pertussis vaccines were examined on a mouse model. ► Aged male mice were more sensitive to PTx than younger or female mice in HIST assays based on lethality or rectal temperature measurement. ► Sensitivity to PTx was further enhanced by the addition of LPS in the HIST. ► With these improvements PTx as low as 12.5 ng could be detected in both HIST assays.