Comparison of adherence to and penetration of a human laryngeal epithelialcell line by group A streptococci of various M protein types

Clinically isolated group A streptococci (GAS) of different M protein types were studied using aminoglycoside exclusion and [2,8-H-3]adenine radiolabe led GAS assays to compare the abilities of different strains to adhere to a nd internalize within human laryngeal epithelial (HEp-2) cells. GAS isolate d from patients with pharyngitis and GAS isolated from patients with more s evere disease, such as necrotizing fasciitis, adhered to and penetrated HEp -2 cells equally well. M3, M4, M6, and M12 strains adhered to and were inte rnalized within HEp-2 cells more than M1 strains. M18 GAS producing hyaluro nic acid capsules were less adherent and less invasive than the M3, M4, M6, and M12, strains. An M3-producing GAS strain and its M protein-deficient i sogenic strain adhered similarly to HEp-2 cells, but the M protein-deficien t strain exhibited greater penetration. Preincubation of HEp-2 cells with a n N-terminal synthetic M3 peptide did not alter the adherence or penetratio n by an M3 strain. In summary, this study demonstrates that GAS from invasi ve and non-invasive disease adhere to and penetrate HEp-2 cells equally wel l and that multiple strains of GAS with various M protein types have the ab ility to adhere to and penetrate HEp-2 cells. (C) 1999 Federation of Europe an Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.