Antibody Binding and Complement-Mediated Killing of Invasive Haemophilus influenzae Isolates from Spain, Portugal, and the Netherlands.
Infect Immun
; 88(10)2020 09 18.
Article
in En
| MEDLINE
| ID: mdl-32719154
ABSTRACT
Haemophilus influenzae is a Gram-negative bacterium that can be classified into typeable (types a through f) and nontypeable (NTHi) groups. This opportunistic pathogen asymptomatically colonizes the mucosal epithelium of the upper respiratory tract, from where it spreads to other neighboring regions, potentially leading to disease. Infection with NTHi can cause otitis media, sinusitis, conjunctivitis, exacerbations of chronic obstructive pulmonary disease, and pneumonia, but it is increasingly causing invasive disease, including bacteremia and meningitis. Invasive NTHi strains are more resistant to complement-mediated killing. However, the mechanisms of complement resistance have never been studied in large numbers of invasive NTHi strains. In this study, we determined the relationship between binding of IgG or IgM and the bacterial survival in normal human serum for 267 invasive H. influenzae strains from Spain, Portugal, and the Netherlands, of which the majority (200 [75%]) were NTHi. NTHi bacteria opsonized with high levels of IgM had the lowest survival in human serum. IgM binding to the bacterial surface, but not IgG binding, was shown to be associated with complement-mediated killing of NTHi strains. We conclude that evasion of IgM binding by NTHi strains increases survival in blood, thereby potentially contributing to their ability to cause severe invasive diseases.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Complement System Proteins
/
Immunoglobulin M
/
Haemophilus influenzae
/
Haemophilus Infections
Limits:
Adult
/
Aged
/
Female
/
Humans
/
Male
/
Middle aged
Country/Region as subject:
Europa
Language:
En
Journal:
Infect Immun
Year:
2020
Document type:
Article
Affiliation country:
Netherlands