Internalization and coreceptor expression are critical for TLR2-mediated recognition of lipoteichoic acid in human peripheral blood.
J Immunol
; 185(6): 3708-17, 2010 Sep 15.
Article
en En
| MEDLINE
| ID: mdl-20713893
ABSTRACT
Lipoteichoic acid (LTA), a ubiquitous cell wall component of Gram-positive bacteria, represents a potent immunostimulatory molecule. Because LTA of a mutant Staphylococcus aureus strain lacking lipoproteins (Deltalgt-LTA) has been described to be immunobiologically inactive despite a lack of ascertained structural differences to wild-type LTA (wt-LTA), we investigated the functional requirements for the recognition of Deltalgt-LTA by human peripheral blood cells. In this study, we demonstrate that Deltalgt-LTA-induced immune activation critically depends on the immobilization of LTA and the presence of human serum components, which, to a lesser degree, was also observed for wt-LTA. Under experimental conditions allowing LTA-mediated stimulation, we found no differences between the immunostimulatory capacity of Deltalgt-LTA and wt-LTA in human blood cells, arguing for a limited contribution of possible lipoprotein contaminants to wt-LTA-mediated immune activation. In contrast to human blood cells, TLR2-transfected human embryonic kidney 293 cells could be activated only by wt-LTA, whereas activation of these cells by Deltalgt-LTA required the additional expression of TLR6 and CD14, suggesting that activation of human embryonic kidney 293 cells expressing solely TLR2 is probably mediated by residual lipoproteins in wt-LTA. Notably, in human peripheral blood, LTA-specific IgG Abs are essential for Deltalgt-LTA-mediated immune activation and appear to induce the phagocytic uptake of Deltalgt-LTA via engagement of FcgammaRII. In this study, we have elucidated a novel mechanism of LTA-induced cytokine induction in human peripheral blood cells that involves uptake of LTA and subsequent intracellular recognition driven by TLR2, TLR6, and CD14.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Staphylococcus aureus
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Ácidos Teicoicos
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Adyuvantes Inmunológicos
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Lipopolisacáridos
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Receptor Toll-Like 2
Límite:
Humans
Idioma:
En
Revista:
J Immunol
Año:
2010
Tipo del documento:
Article
País de afiliación:
Alemania