Image Number 5 for United States Patent #5543304.
A protein derivable from Actinobacillus pleuropneumoniae (APP) having a molecular size ranging between 43 Kd on SDS PAGE is described. The protein is soluble on sodium lauryl sarcosinate (SLS) and not heat modifiable. The protein can also be derived by recombinant methods. The protein in a vaccine provides immunity against multiple serotypes of APP.