Haemophilus influenzae reside in tonsills and use IgD binding as an evasion strategy.

Summary, in English

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.

• Author: Kalpana Singh; Therése Nordström; Matthias Mörgelin; Marta Brant; Lars-Olaf Cardell; Kristian Riesbeck
• Department/s: Clinical Microbiology, Malmö; Infection Medicine (BMC); Clinical and Experimental Allergy Research
• Publishing year: 2014
• Language: English
• Pages: 1418-1428
• Publication/Series: Journal of Infectious Diseases
• Volume: 209
• Issue: 9
• Links: http://www.ncbi.nlm.nih.gov/pubmed/24218509?dopt=Abstract; http://dx.doi.org/10.1093/infdis/jit593
• Document type: Journal article
• Publisher: Oxford University Press
• Topic: Infectious Medicine
• Status: Published
• Research group: Clinical Microbiology, Malmö; Clinical and Experimental Allergy Research
• ISBN/ISSN/Other: ISSN: 1537-6613