Antisera were produced against the E. tracheiphila type strain (ATCC,33245) and MD1, a field-collected strain (Table 1). Broth cultures grown in Difco nutrient broth with extra peptone (5 g/liter)
(NBP) were washed twice in phosphatebuffered saline (PBS) and resuspended in 2 ml of PBS. Cells of each isolate were fixed
with 2% glutaraldehyde and then washed by pelleting and resuspending three times in PBS.