| 1. |
- Jalalvand, Farshid, et al.
(författare)
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Haemophilus influenzae Protein F Mediates Binding to Laminin and Human Pulmonary Epithelial Cells.
- 2012
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Ingår i: Journal of Infectious Diseases. - : Oxford University Press (OUP). - 1537-6613 .- 0022-1899. ; 207:5, s. 803-813
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Tidskriftsartikel (refereegranskat)abstract
- The mucosal pathogen non-typeable Haemophilus influenzae (NTHi) adheres to the respiratory epithelium, or in the case of epithelial damage, to the underlying basement membrane and extracellular matrix that amongst other proteins consists of laminin. We have recently identified Protein F, an ABC-transporter involved in NTHi immune evasion. Homology modeling of the Protein F tertiary structure revealed a strong resemblance to the streptococcal laminin-binding proteins Lbp and Lmb. Here, we show that Protein F promotes binding of NTHi to laminin and primary bronchial epithelial cells. Analyses with recombinant proteins and synthetic peptides revealed that the N-terminal part of Protein F contains the host-interacting region. Moreover, Protein F exists in all clinical isolates, and isogenic NTHi Δhpf mutants display significantly reduced binding to laminin and epithelial cells. We thus suggest Protein F as an important and ubiquitous NTHi adhesin.
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| 2. |
- Singh, Birendra, et al.
(författare)
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Protein E of Haemophilus influenzae Is a Ubiquitous Highly Conserved Adhesin.
- 2010
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Ingår i: Journal of Infectious Diseases. - : Oxford University Press (OUP). - 1537-6613 .- 0022-1899. ; 201, s. 414-419
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Tidskriftsartikel (refereegranskat)abstract
- Protein E (PE) of nontypeable Haemophilus influenzae (NTHi) is involved in adhesion and activation of epithelial cells. A total of 186 clinical NTHi isolates, encapsulated H. influenzae, and culture collection strains were analyzed. PE was highly conserved in both NTHi and encapsulated H. influenzae (96.9%-100% identity without the signal peptide). PE also existed in other members of the genus Pasteurellaceae. The epithelial cell binding region (amino acids 84-108) was completely conserved. Phylogenetic analysis of the pe sequence separated Haemophilus species into 2 separate clusters. Importantly, PE was expressed in 98.4% of all NTHi (126 isolates) independently of the growth phase.
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| 3. |
- Singh, Kalpana, et al.
(författare)
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Haemophilus influenzae reside in tonsills and use IgD binding as an evasion strategy.
- 2014
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Ingår i: Journal of Infectious Diseases. - : Oxford University Press (OUP). - 1537-6613 .- 0022-1899. ; 209:9, s. 1418-1428
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Tidskriftsartikel (refereegranskat)abstract
- Haemophilus influenzae (Hi) causes respiratory tract infections and is also considered as a commensal, particularly in pre-school children. Tonsils from patients (n=617) undergoing tonsillectomy due to chronical infection or hypertrophy were examined. We found that 51 % of tonsils were positive for Hi, and in 95 % of cases analysed in detail (n=39) Hi resided intracellularly in the core tonsillar tissue. Patients harboured several intracellular unique strains and the majority were non-typeable Hi (NTHi). Interestingly, the isolated NTHi bound soluble immunoglobulin (Ig) D at the constant heavy chain domain 1 as revealed by recombinant IgD/IgG chimeras. NTHi also interacted with B lymphocytes via the IgD B cell receptor resulting in internalization of bacteria, T-cell independent activation via Toll like receptor 9, and differentiation into non-NTHi specific IgM producing cells. Taken together, IgD-binding NTHi leads to an unspecific immune response and may support the bacteria to circumvent the host defense.
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