PRODUCTION AND CHARACTERIZATION OF MONOCLONAL-ANTIBODIES AGAINST ACTINOBACILLUS-PLEUROPNEUMONIAE SEROTYPE-1

Three monoclonal antibodies (mAbs) against Actinobacillus pleuropneumo niae serotype 1, designated 4.2 A11 B5, 5.1 G8 F10 and 1.5 C5 F4 (lgG3 , lgG2b and lgM respectively), were produced and characterized. mAbs 4 .2 A11 B5 and 5.1 G8 F10 were directed against different epitopes loca ted in the O chain of the LPS. Both clones also recognized reference s trains of A. pleuropneumoniae serotypes 9 and 11. The mAb 1.5 C5 F4 re acted with the reference strain of A. pleuropneumoniae serotype 1, wit h the encapsulated strain 4045 (but not with its non-capsulated mutant ) and with A. pleuropneumoniae serotype 1 purified capsular polysaccha rides (CPS). The epitope was sensitive to periodate oxidation, heat-la bile, and located in the capsular material of A. pleuropneumoniae sero type 1, as demonstrated by immunoblotting. Treatment of the CPS with 5 % ammonium hydroxide eliminated the reaction, which may indicate that the epitope recognized by 1.5 C5 F4 mAb is a O-acetyl containing deter minant. When different A. pleuropneumoniae field strains were tested, the percentage of strains recognized by the mAbs varied with the mAb a nd the test used. Cross-reactions associated with the LPS of some A. p leuropneumoniae serotype 5 field strains could be observed with the 4. 2 A11 B5 mAb. Of the three mAbs characterized, 1.5 C5 F4 seemed to be the most suitable for A. pleuropneumoniae serotype 1 detection since i t reacted with 99% of serotype 1 field strains and it did not recogniz e any of the strains belonging to other serotypes.