Evaluation of a panel of monoclonal antibodies in the subtyping of Haemophilus paragallinarum.

A panel of four monoclonal antibodies (MAbs) was evaluated, using a hemagglutination-inhibition test, for its ability to subtype 76 isolates of Haemophilus paragallinarum. The results of the MAb reactions were compared with the results of both the Page and Kume serotyping schemes (the serovars of the Page scheme correspond to the serogroups of the Kume scheme). One MAb (E5C12D10) was raised against a Page serovar A strain and the remaining MAbs (F2E6, D6D8D5, and B3E6F9) against a Page serovar C strain. Six different reaction patterns were found among the 76 isolates of H. paragallinarum. There was total correlation between the MAb reaction pattern and the Page scheme, and thus the Kume scheme, to the serogroup level. All 19 Page serovar A (= Kume serogroup A) strains reacted only with MAb E5C12D10, whereas all five Page serovar B (= Kume serogroup B) strains failed to react with any of the MAbs. All 52 remaining strains were Page serovar C (= Kume serogroup C), and all failed to react with MAb E5C12D10 but showed varying reaction patterns with the three other MAbs. Although the MAbs recognized four subdivisions within Kume serogroup C, these subdivisions differed from the four Kume C serovars. This panel of MAbs can be used to assign isolates of H. paragallinarum to either Page serovars or Kume serogroups. Although the subdivisions recognized by the MAbs within the Page serovar C strains do not correspond to the Kume serovars, they may be useful in epidemiological applications.