Identification of common antigens in ribosome-rich extracts from Fusobacterium necrophorum

Ribosome-rich extracts (RRE) were prepared by differential and ultracentrifugation from 25 bovine and 6 ovine isolates of Fusobacterium necrophorum (FN) including both biotypes A and B. A pooled rabbit antiserum was prepared against whole-cell and sonicated whole-cell bacterins of F necrophorum isolate FN 3080, and a 2nd pooled rabbit antiserum was prepared against a RRE of FN 3080. The RRE of the 25 bovine isolates were tested against the FN 3080 whole-cell antiserum, using Ouchterlony double-immunodiffusion procedures. One to 3 precipitin lines were observed with the 25 isolates. The individual bovine isolates were found to have lines of identity with 5 to 21 of the other 24 isolates. The 25 bovine isolates and the 6 ovine isolates were then compared, using the FN 3080 RRE antiserum. One to 3 precipitin lines were observed for the 31 isolates with the RRE antiserum, and lines of identity were observed between all 31 of the isolates. These results indicated that common antigens are present in the RRE from a wide variety of F necrophorum isolates including both A and B biotypes.