Fig 4.

Serological response to pertussis toxin in B. pertussis-infected baboons. (A) Once prior to and on the indicated range of days after inoculation, sera were collected and anti-PT IgG was measured by ELISA as described in Materials and Methods (n = 7 for all time points except for days 117 to 131, for which n = 4). Data are presented as relative units (percent anti-PT IgG compared to a standard). (B) The complete anti-PT IgG kinetics for two of the seven baboons are shown. **, P < 0.01; ***, P < 0.001 versus preinfection.