Essential role for CCR6 in certain inflammatory diseases demonstrated using specific antagonist and knockin mice
Remy Robert, Caroline Ang, Guizhi Sun, Laurent Juglair, Ee X. Lim, Linda J. Mason, Natalie L. Payne, Claude C.A. Bernard, Charles R. Mackay
Remy Robert, Caroline Ang, Guizhi Sun, Laurent Juglair, Ee X. Lim, Linda J. Mason, Natalie L. Payne, Claude C.A. Bernard, Charles R. Mackay
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Research Article Therapeutics

Essential role for CCR6 in certain inflammatory diseases demonstrated using specific antagonist and knockin mice

Abstract

The chemokine receptor CCR6 marks subsets of T cells and innate lymphoid cells that produce IL-17 and IL-22, and as such may play a role in the recruitment of these cells to certain inflammatory sites. However, the precise role of CCR6 has been controversial, in part because no effective monoclonal antibody (mAb) inhibitors against this receptor exist for use in mouse models of inflammation. We circumvented this problem using transgenic mice expressing human CCR6 (hCCR6) under control of its native promoter (hCCR6-Tg/mCCR6–/–). We also developed a fully humanized mAb against hCCR6 with antagonistic activity. The expression pattern of hCCR6 in hCCR6-Tg/mCCR6–/– mice was consistent with the pattern observed in humans. In mouse models of experimental autoimmune encephalomyelitis (EAE) and psoriasis, treatment with anti-hCCR6 mAb was remarkably effective in both preventive and therapeutic regimens. For instance, in the imiquimod model of psoriasis, anti-CCR6 completely abolished all signs of inflammation. Moreover, anti-hCCR6 attenuated clinical symptoms of myelin oligodendrocyte glycoprotein–induced (MOG-induced) EAE and reduced infiltration of inflammatory cells in the central nervous system. CCR6 plays a critical role in Th17 type inflammatory reactions, and CCR6 inhibition may offer an alternative approach for the treatment of these lesions.

Authors

Remy Robert, Caroline Ang, Guizhi Sun, Laurent Juglair, Ee X. Lim, Linda J. Mason, Natalie L. Payne, Claude C.A. Bernard, Charles R. Mackay

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Figure 3

Anti-hCCR6 mAb prevents and inhibits EAE in hCCR6-Tg/mCCR6–/– mice.

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Anti-hCCR6 mAb prevents and inhibits EAE in hCCR6-Tg/mCCR6–/– mice. (A) ...
(A) Experimental autoimmune encephalomyelitis (EAE) preventive study. Blockade of human CCR6 (hCCR6) with humanized 6H12 (h6H12) mAb (2 mg/kg, black arrows) prevents the development of EAE in hCCR6-Tg/mCCR6–/– mice immunized with recombinant mouse (rm) myelin oligodendrocyte glycoprotein (MOG). (B) Kaplan–Meier plot of the proportion of disease-free animals after EAE induction in isotype (n = 18, black line) versus h6H12 Fc-KO–treated (n = 20, red line) and anti–mIL-17 mAb–treated animals (n = 11, blue line) (Mantel-Cox log-rank test). (D) Maximum and (C) cumulative disease scores in isotype- (n = 18), h6H12 Fc-KO– (n = 20), and anti–mIL-17 mAb–treated mice (n = 11). (E) Representative stained histological sections of spinal cords from immunized animals treated with isotype control (top panels), h6H12 Fc-KO (middle panels), or anti–mIL-17 (bottom panels). Serial sections were stained with H&E to determine the degree of inflammatory cell infiltrates, luxol fast blue (LFB) to establish myelin integrity, and Bielschowsky silver stain (BSS) to ascertain axonal loss and damage (white arrows indicate area of leukocyte infiltration). Scale bar: 200 μm. (F) Histological scores for inflammation (H&E), demyelination (LFB), and axonal damage (BSS) (blacks bars, isotype control [n = 9]; blue bars, anti–mIL-17 [n = 8]; red bars, h6H12 Fc-KO [n = 9]). (G) EAE therapeutic study. Injections of h6H12 (5 mg/kg; black arrow) significantly reduce the disease development (n = 12, red curve) compared with mice treated with an isotype control mAb (n = 12, black curve) or anti–mIL-17 mAb (n = 8, blue curve). The clinical course of EAE (A and G) was analyzed with the nonparametric Kruskal-Wallis ANOVA with the Dunn’s post-hoc test. Histological, maximum clinical, and cumulative scores (C, D, and F) were compared by 1-way ANOVA with Dunnett’s multiple comparisons test relative to the control isotype–treated group. *P < 0.05, **P < 0.01, ***P < 0.001.