Purification of a cross-protective antigen from Pasteurella multocida grown in vitro and in vivo

A peptone-based medium was formulated to grow Pasteurella multocida in vitr o, which expressed an antigen that induces cross protection in turkeys agai nst different serotypes. Vaccines of various chromatographic fractions obta ined from I? multocida grown in the medium induced active immune cross prot ection in turkeys, and sera from these turkeys passively cross protected na ive poults. An antigen of approximately 39 kD molecular size was purified b y preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis and electroelution from hydroxyapatite chromatographic fractions of both in vi vo- and in vitro-grown P. multocida. The purified antigen from either sourc e induced active immune cross protection but no passive protection in one o f two experiments. Increasing the dose of vaccine resulted in both active a nd passive immune cross protection in the second experiment.