Article

A distinct Toll‐like receptor repertoire in human tonsillar B cells, directly activated by Pam3CSK4, R‐837 and CpG‐2006 stimulation

Laboratory of Clinical and Experimental Allergy Research, Department of Otorhinolaryngology, Malmö University Hospital, Lund University, Sweden
Immunology (impact factor: 3.32). 07/2006; 118(4):539 - 548. DOI:10.1111/j.1365-2567.2006.02392.x pp.539 - 548

ABSTRACT Toll-like receptors (TLRs) recognize specific pathogen-associated molecular patterns (PAMPs), which subsequently trigger innate immunity. Recent data also suggest a role for TLRs in the direct activation of adaptive immune cells. In the present study, the expression and function of TLR1–TLR10 were characterized in purified human tonsillar B cells, focusing on differences among CD19+ CD38– CD27– (naïve B cells), CD19+ IgD– CD27–[germinal centre (GC) B cells] and CD19+ CD38– CD27+ (memory B cells) cells. The study was also designed to compare the TLR expression in B cells obtained from infected and hyperplastic tonsils that served as controls. The results demonstrated a distinct repertoire of TLRs, in which TLR1, TLR2, TLR7, TLR9 and TLR10 predominated. No differences were found among naïve, GC and memory B cells. Tonsillar infection did not substantially alter the TLR expression profile in ex vivo-isolated B-cell subsets. Purified CD19+ B cells stimulated with Pam3CSK4, R-837 and CpG oligodeoxynucleotide (ODN) 2006, via TLR1/TLR2, TLR7 and TLR9, respectively, showed an induction of interleukin-6 secretion and an up-regulated expression of human leucocyte antigen (HLA)-DR. Collectively, the present study demonstrates that B cells exhibit constitutively high levels of specific TLRs, which are not developmentally regulated during the B-cell differentiation process. Ongoing microbial infections, such as chronic tonsillitis, do not appear to affect the TLR profile in B cells. Furthermore, the distinct expression of TLRs allows B cells to respond directly to the cognate PAMPs. This further emphasizes the role of TLRs in directly activating adaptive immune cells.

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Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.

Keywords

activating adaptive immune cells
 
adaptive immune cells
 
B cells
 
B cells exhibit constitutively
 
B-cell differentiation process
 
chronic tonsillitis
 
cognate PAMPs
 
CpG oligodeoxynucleotide
 
ex vivo-isolated B-cell subsets
 
human leucocyte antigen
 
hyperplastic tonsils
 
memory B cells
 
naïve B cells
 
Ongoing microbial infections
 
Purified CD19+ B cells
 
purified human tonsillar B cells
 
specific TLRs
 
TLR expression profile
 
TLR10 predominated
 
trigger innate immunity