CORRELATION BETWEEN HEMAGGLUTINATING ANTIBODY AND MOUSE PROTECTION IN ANTIPASTEURELLA (PASTEURELLA MULTOCIDA) SERA

Rabbits were immunized against types B and E Pasteurella multocida. The protective capacities of the sera were determined by mouse protection tests. The HA titers of these sera were determined by a standardized indirect hemagglutination test. A linear relation was observed when the protective values of the immune sera (log of the number of LD50's against which the mean of the ED50's (4.25 × 10−2 ml) protects 50% of mice) were plotted against the logs of the HA titers of the same sera.