Characterization of murine immune response to PRT/H. (A) Time course of murine immune response to PRT/H (n = 10). C57Bl/6 mice were immunized with PRT/H (PRT 125 μg/mL and H 12.5 U/mL) and antibody levels were followed over a time period of 30 days. Each line represents the seroconversion profile of an individual mouse injected with PRT/H. Figure insert shows the serologic response of individual mice injected with PRT alone over 30 days. (B) Stoichiometry of the immune response to PRT/H: Mice (n = 10/cohort) were immunized with a fixed amount of PRT (125 μg/mL) and varying H doses (0, 5, 10, 12.5, 25, and 50 U/mL) to yield varying PRT:H molar ratios as shown above (−, 8:1, 4:1, 3:1, 1.5:1, or 1:1.2). Results of antibody levels are shown at D15.