Evaluation of two monoclonal antibodies for serotyping Haemophilus paragallinarum

Two monoclonal antibodies (MAbs) were evaluated for their ability to serotype 108 isolates of Haemophilus paragallinarum. One MAb (E5C12D10) was raised against a Page serovar A strain and the other (F2E6) against a Page serovar C strain. In both dot blot and hemagglutination-inhibition tests, MAb E5C12D10 recognized the type strains of Page serovar A and Kume serovars A-1, A-2, A-3, and A-4. MAb F2E6 recognized the type strains of Page serovar C and Kume serovars C-1, C-2, and C-3. Neither antibody recognized the type strains of Page serovar B or Kume serovars B-1 and C-4. When evaluated with 97 field isolates in a dot blot test, the MAbs serotyped 81 isolates, which was better than agglutinin typing by the Page scheme (69 isolates serotyped). The field isolates that did not react with the MAbs were either Page serovar B/Kume serovar B-1 (three isolates), Page serovar C/Kume serovar C-4 (12 isolates), or nontypable by either the Page or Kume scheme (one isolate).