Identification of an Interleukin 17F/17A Heterodimer in Activated Human CD4+ T Cells

Jill F Wright,Yongjing Guo,Amira Quazi,Deborah P Luxenberg,Frann Bennett,John F Ross,Yongchang Qiu,Matthew J Whitters,Kathleen N Tomkinson,Kyri Dunussi-Joannopoulos,Beatriz M Carreno,Mary Collins,Neil M Wolfman

doi:10.1074/jbc.m700499200

Jill F Wright, Yongjing Guo + Show 11 more

Open Access

https://doi.org/10.1074/jbc.m700499200

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Abstract

IL-17F and IL-17A are members of the IL-17 pro-inflammatory cytokine family. IL-17A has been implicated in the pathogenesis of autoimmune diseases. IL-17F is a disulfide-linked dimer that contains a cysteine-knot motif. We hypothesized that IL-17F and IL-17A could form a heterodimer due to their sequence homology and overlapping pattern of expression. We evaluated the structure of recombinant IL-17F and IL-17A proteins, as well as that of natural IL-17F and IL-17A derived from activated human CD4+ T cells, by enzyme-linked immunosorbent assay, immunoprecipitation followed by Western blotting, and mass spectrometry. We find that both IL-17F and IL-17A can form both homodimeric and heterodimeric proteins when expressed in a recombinant system, and that all forms of the recombinant proteins have in vitro functional activity. Furthermore, we find that in addition to the homodimers of IL-17F and IL-17A, activated human CD4+ T cells also produce the IL-17F/IL-17A heterodimer. These data suggest that the IL-17F/IL-17A heterodimer may contribute to the T cell-mediated immune responses.

Highlights

Expression of IL-17F and IL-17A has been detected in activated human peripheral blood lymphocytes
Cytokine expression in the conditioned medium was determined by ELISA analysis, using capture and detection antibodies that were specific for either IL-17F or IL-17A or IL-17F/IL-17A heterodimer
When immunoprecipitation was carried out using an anti-huIL-17A specific antibody and an anti-huIL-17F antibody was used for Western detection, a band corresponding to the IL-17F/IL-17A heterodimer was only seen in the co-transfected conditioned medium, and not in the singly transfected medium (Fig. 2B, lanes 5–7)

Summary

Introduction

Expression of IL-17F and IL-17A has been detected in activated human peripheral blood lymphocytes. List of inter-protein disulfide-linked peptides identified from the purified recombinant IL-17F and IL-17A homodimers as well as the IL-17F/IL-17A heterodimer. Cytokine expression in the conditioned medium was determined by ELISA analysis, using capture and detection antibodies that were specific for either IL-17F or IL-17A or IL-17F/IL-17A heterodimer (see supplementary data).

Results

Conclusion