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Therapeutic factor VIII does not trigger TLR 1.2 and TLR 2.6 signalling in vitro
Author(s) -
Teyssandier M.,
André S.,
Gupta N.,
Dasgupta S.,
Bayry J.,
Kaveri S. V.,
LacroixDesmazes S.
Publication year - 2013
Publication title -
haemophilia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.213
H-Index - 92
eISSN - 1365-2516
pISSN - 1351-8216
DOI - 10.1111/hae.12081
Subject(s) - zymosan , immune system , antigen , transfection , immunology , tlr2 , toll like receptor , flow cytometry , medicine , in vitro , microbiology and biotechnology , cell culture , innate immune system , biology , biochemistry , genetics
Summary The administration of therapeutic factor VIII ( FVIII ) to patients with haemophilia A induces the development of inhibitory anti‐ FVIII IgG in a substantial number of patients. For an antigen‐specific immune response to develop, antigen‐presenting cells ( APC s) need to mature and procure appropriate co‐stimulatory signals to T cells at the time of presentation of the endocytosed antigen. The nature of the danger signals that induce APC maturation, thus initiating the anti‐ FVIII immune response, are yet ill‐characterized. Contradictory reports on a direct effect of therapeutic FVIII on APC maturation have been released. Here, we investigated whether FVIII directly triggers T oll‐like receptor 2 ( TLR 2) signalling. The capacity of human recombinant FVIII to promote the maturation of a mouse bone marrow macrophage cell line (BMA) was investigated by flow cytometry. In parallel, the triggering of TLR 1.2 or TLR 2.6‐expressing HEK 293 cells by FVIII was analysed following transfection of the cells with a reporter construct for NF κB activity. In contrast, to zymosan, a known TLR 2 agonist, human recombinant FVIII did not induce the maturation of mouse BMA macrophages, as analysed by the levels of expression of CD 80, CD 86, CD 40 and I‐Ab at the cell surface. Furthermore, incubation of FVIII with cells expressing TLR 2 paired with TLR 1 or TLR 6, failed to activate NF κB, whereas NK κB activity was triggered in the presence of zymosan. Our results confirm that FVIII alone is insufficient to trigger the maturation of APC s that is required to initiate an immune response.