Adhesive properties of Haemophilus influenzae to different human cells

The adhesion of 19 nontypable strains and 3 typable (type b) Haemophilus influenzae to human cells was examined using buccal epithelial cells (BEC), the continuous HEp-2 cell line and human 0 erythrocytes. The strains were classified into three phenotypes, according to their adhesive properties. Phenotype 1 consists of strains that adhere to both buccal epithelial cells and HEp-2 cells. Phenotype 2 consists of strains that adhere to both buccal epithelial cells and erythrocytes and strains belonging to phenotype 3 adhere to none of the three cell types used. Among 22 strains studied, 18 (81.8%) belonged to phenotype 1, 2 (9.1%) to phenotype 2 and 2 (9.1%) to phenotype 3. Fimbriae were observed for 11 (61%) among the 18 adherent strains belonging to phenotype 1. The 7 nonpiliated strains adhered with a significant adhesion index, thus this results would indicate that a non fimbrial adhesin exists.