Abstract
We have purified and characterized pili from clinical isolates of H. influenzas. Pilus preparations were highly pure by multiple criteria and consisted of intact rods composed of a 25K dalton subunit. Amino acid sequence analysis revealed a high degree of N-terminus homology with E. coli type 1 and P pili, suggesting a common gene ancestry. Purified pili hemagglutinated human type O RBCs and were used in a microtiter plate assay incorporating synthetic saccharides to identify the pilus receptor. Pilus receptor binding by purified pili and piliated H. influenzas was blocked by homologous and heterologous anti-pilus antiserum. Receptor binding inhibition was pilus-specific antibody concentration dependent, but was observed even with antisera showing <10% cross-reactivity. Purified pili were highly immunogenic, with homologous ELISA titers ranging from 3 × 105 to 106. Heterologous titers ranged from 2% – 100% homologous titers with 40% of the strains tested showing >50% cross-reactivity. Pili from type b and non-typable strains were serologically, chemically and functionally similar. H. influenzae and E. coli P pili were serologically related but differed in receptor specificity suggesting functional divergence. These results indicate that there are a relatively small number of major antigenic groups of H. influenzae pili which may be important to the development of a pilus vaccine.
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Guerina, N., Langermann, S., Schoolnik, G. et al. 1106 CHEMICAL, SEROLOGICAL, AND FUNCTIONAL ANALYSES OF PURIFIED H. INFLUENZAE PILI. Pediatr Res 19, 295 (1985). https://doi.org/10.1203/00006450-198504000-01136
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DOI: https://doi.org/10.1203/00006450-198504000-01136