ABSTRACTS – ORAL PRESENTATIONS - AMCA, spol. s r.o.

P22. HUMAN INTERLEUKIN-23 RECEPTOR ANTAGONISTS DERIVED FROM AN
ALBUMIN-BINDING DOMAIN SCAFFOLD INHIBIT IL-23-DEPENDENT EX VIVO
EXPANSION OF IL-17-PRODUCING T-CELLS
Ondřej Pelák 1 , Milan Kuchař 2 , Lucie Vaňková 2 , Hana Petroková 2 , Jiří Černý 3 , Radim
Osička 4 , Hana Šípová 5 , Bohdan Schneider 3 , Jiří Homola 5 , Peter Šebo 2,4 , Tomáš Kalina 1
and Petr Malý 2
1
Department of Pediatric Hematology and Oncology, 2 nd Faculty of Medicine, Charles
University and University Hospital Motol, Prague, Czech Republic
2
Laboratory of Ligand Engineering and 3 Laboratory of Molecular Recognition, Institute
of Biotechnology AS CR, v. v. i., Vídeňská 1083, 142 20 Prague, Czech Republic
4
Institute of Microbiology AS CR, v. v. i., Vídeňská 1083, 142 20 Prague, Czech Republic
5
Institute of Photonics and Electronics AS CR, v. v. i., Chaberská 57, 182 51, Prague,
Czech Republic
pelak.ondrej@gmail.com
Autoimmune diseases such as psoriasis, Crohn’s disease, rheumatoid arthritis or multiple
sclerosis, have recently been found to be associated with IL-23-mediated signaling and
increased TH17 lymphocytes. Thus, inhibition of IL-23 might provide therapeutic effect.
Engineered recombinant binders from small protein scaffolds of the albumin binding
domain of streptococcal protein G can be generated with binding affinities similar to
monoclonal antibodies. These binders can exert inhibitory function by blocking of the
cytokine binding epitope on its receptor.
We tested the inhibition effect of recombinant binders of human interleukin-23 receptor
(IL-23R) on primary human CD4+ T-cells. Peripheral mononuclear cells (PBMNC) were
isolated from blood of healthy donors and stimulated with anti-CD3 antibody and
co-stimulated by activating antibodies CD28 and CD49d in presence of the TH-17
conditioning cytokines Il-23 and Il-2 for 3 days. After 3 days the intracellular cytokine
staining protocol was used to detect production of IL-17 and INF-γ to see the inhibition
effect of novel IL-23R-binding proteins. We show that presence of REX009, REX115 and
REX125 variants of the IL-23R-binding proteins inhibited the IL-23-driven expansion of
IL-17- producing primary human CD4+ T-cells even by 75%.
To confirm direct inhibitory effect of REX binders on T-cells, we repeated the same
experiment in samples with separated T-cells with similar results.
In summary, we show that REX variants inhibited IL-23-dependent TH-17+ cell expansion
to the level of samples with no IL-23 added. While IL-23 was shown to promote the
development of TH-17+ T-cells in man, the mode of this action might be fixing the TH-
17 commitment rather than “de novo” TH-17 development, survival or proliferation
enhancement (Stritesky et al, 2008).
References
Stritesky GL, Yeh N, Kaplan MH. IL-23 promotes maintenance but not commitment to the
Th17 lineage. J Immunol 2008;181(9):5948-5955.
Acknowledgement
OP and TK are supported by MH CR, DRO 00064203
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