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Involvement of Toll-Like Receptor 4 and Fc Receptors Gamma in Human Neutrophil Priming by Endotoxins from Escherichia coli

D. S. Kabanov* and I. R. Prokhorenko

Institute of Basic Biological Problems, Russian Academy of Sciences, ul. Institutskaya 2, 142290 Pushchino, Moscow Region, Russia; fax: (4967) 33-0532; E-mail: kabanovd1@rambler.ru

* To whom correspondence should be addressed.

Received July 10, 2012; Revision received October 6, 2012
By using the fMLP-induced respiratory burst approach, the involvement of Toll-like receptor 4 (TLR4) in human neutrophil priming by S- or Re-glycoforms of endotoxin from Escherichia coli has been elucidated. The priming effect of Re-glycoform is more pronounced than that of the S-glycoform. Unexpectedly, fMLP-triggered generation of reactive oxygen species (ROS) by endotoxin primed neutrophils was amplified by preincubation of the cells with anti-TLR4 (HTA125) antibodies or with isotype-matched immunoglobulin IgG2a. The most significant finding of our study is that neutrophils exposed to anti-TLR4 antibodies retain their ability to distinguish between S- or Re-glycoforms being primed, respectively. Moreover, differentiated effect of HTA125 antibodies on functional responses of neutrophils during their priming and fMLP stimulation was revealed. Taking these results into consideration, it is reasonable to assume that there is a contribution of Fcγ receptors to fMLP-induced ROS generation by neutrophils preincubated with HTA125 or IgG2a and primed by endotoxins.
KEY WORDS: lipopolysaccharide (endotoxin), Toll-like receptor 4, receptor cluster, Fcγ receptors, IgG2a, anti-human TLR4 antibody, reactive oxygen species

DOI: 10.1134/S0006297913020077