Cytokine. 2014 Aug;68(2):86-93.

Ingested (oral) tocilizumab inhibits EAE.

Brod SA1, Bauer VL2.
  • 1Department of Neurology, University of Texas-Houston, Health Science Center, 6431 Fannin St, Houston, TX 77030, United States. Electronic address: staley.a.brod@uth.tmc.edu.
  • 2Department of Neurology, University of Texas-Houston, Health Science Center, 6431 Fannin St, Houston, TX 77030, United States.

 

Abstract

BACKGROUND: Blocking the activity of IL-6 can inhibit autoimmune diseases such as rheumatoid arthritis and Crohn’s disease.

OBJECTIVE: We examined whether an antibody against IL-6, tocilizumab (TCZ) (Actemra®), used clinically in rheumatoid arthritis (RA) would have similar anti-inflammatory effects in EAE after oral administration.

DESIGN/METHOD: B6 mice were immunized with MOG peptide 35-55 and gavaged with control saline or TCZ during ongoing disease. Splenocytes, CD4(+) T cells or macrophages/monocyte lineage cells (CD11b(+)) from control fed or TCZ fed mice were adoptively transferred into active MOG peptide 35-55 immunized recipient mice during ongoing disease. Actively fed and recipient mice were examined for disease inhibition, inflammation, and cytokine responses.

RESULTS: Ingested (oral) TCZ inhibited ongoing disease and decreased inflammation. Adoptively transferred cells from TCZ fed donors protected against actively induced disease and decreased inflammation. There was a decrease in IL-6 in actively treated spleen, decrease in TNF-α, Th1-like cytokine IL-12 and increase in Th2-like cytokine IL-10 in active fed and adoptively treated recipients.

CONCLUSIONS: Ingested (orally administered) TCZ can inhibit disease, CNS inflammation, decrease pro-inflammatory Th1-like cytokines and increase Th2-like anti-inflammatory cytokines. Copyright © 2014 Elsevier Ltd.

KEYWORDS: Adoptive transfer; Antibody; EAE; Oral proteins; Tocilizumab

PMID: 24845797

 

SUPPLEMENTS:

EAE is a T cell mediated inflammatory CNS autoimmune process that resembles human demyelinating disease MS. In 1/2010, TCZ (RoActemra®; Chugai/Roche), a first-in-class humanized mAb that binds specifically to both sIL-6R and mIL-6R and inhibits IL-6R-mediated signaling was approved for patients with moderate to severe RA unresponsive to available DMARDs. IL-6 transgenic mice developed severe neurologic disease characterized by tremor, ataxia, and seizure.  IL-6-deficient mice were completely resistant to MOG EAE.  IL-6 is elevated in the spinal cord and CSF of mice with active EAE. Because IL-6 may be important in the pathogenesis of EAE and TCZ is a FDA approved product currently used in RA, we asked whether oral TCZ would have a similar anti-inflammatory effect in murine EAE.  If Actemra, a humanized mAb shows activity in EAE, these findings would support direct translation to early clinical trials in MS.

 

CLINICAL:

ACTIVE – Ingested TCZ inhibits clinical EAE attacks (Fig 1). Both 1 and 10 mcg ingested TCZ significantly inhibits clinical EAE progression compared to isotype IgG control  (p < 0.001, ANOVA, day 17-30, group clinical score ± SEM).

1

PASSIVE

a) Adoptively transferred donor cells (fig 2) from TCZ fed immunized mice protect against active EAE. Recipients of TCZ fed donor cells and donor cells incubated with TCZ in vitro decreased their group clinical score significantly compared to recipients of isotype IgG control cells (p < 0.005, days 17-30, ANOVA, day 17-30, group clinical score ± SEM).

2

b) Adoptively transferred donor CD4+ T (fig 3) cells from TCZ fed immunized mice protect against active EAE. Recipients of IgG control fed CD4+ T donor cells increased their group clinical disease severity. Recipients of TCZ fed CD4+ T cells donor cells and CD4+ T cells donor cells incubated with TCZ in vitro decreased their group clinical score significantly compared to recipients of isotype IgG control cells (p < 0.005, days 17-30, ANOVA, group clinical score ± SEM).

3

c) Adoptively transferred donor CD11b+ cells (fig 4) from TCZ fed immunized mice protect against active EAE. Recipients of IgG control fed CD11b+ cells increased their group clinical disease severity. Recipients of TCZ fed CD11b+ donor cells and CD11b+ donor cells incubated with TCZ in vitro decreased their group clinical score significantly compared to recipients of isotype IgG control CD11b+ cells (p < 0.005, days 17-30, ANOVA, group clinical score ± SEM).

4

Adoptive transfer

Recipients of donor cells from TCZ fed mice show decreases in CNS Th1-like IFN-γ cytokines, IL-12, IL-17 and increased Th2-like IL-10 (fig 5). CNS lymphocytes showed decreased levels of Th1-like cytokines IL-12 (p < 0.005, t test), IL-17 (p < 0.01), IFN-γ (p < 0.01) and increased production of IL-10 (p < 0.01) in TCZ dosed vs IgG control dosed mice.

5

Recipients of donor cells from TCZ fed mice show decreases in CNS pro-inflammatory, Th1-like cytokines, and increased Th2-like IL-10 (fig 6). CNS lymphocytes showed decreased levels of TNF-a (p < 0.01, t test), Th1-like cytokines IL-12 (p < 0.01) and increased production of MOG induced IL-10 (p < 0.001) in TCZ dosed vs IgG control mice.

6

Adoptively transferred CD4+ T and CD11b+ cells from TCZ fed donor mice can modulate disease in actively immunized recipients.

Thirteen days following adoptive transfer, the number of CNS inflammatory foci in the fed CD4+ T cell and CD11b+ cell groups were significantly decreased compared to recipients of IgG control fed CD4+ T cells and CD11b+ groups (Table 1).

 

Table 1

Recipients of donor cell subsets from TCZ fed mice have fewer inflammatory foci

tab-1

* p < 0.008; # p < 0.01; n=16/group.  Results are expressed as mean group inflammatory score ± SEM.

 

Spleen cells of recipients of TCZ in vitro treated splenic lymphocytes show decreased IFN-γ and IL-12.

We also wanted to find out if in vitro treatment had similar effects on cytokines compared to in vivo feeding. After TCZ in vitro treatment of whole splenocytes from control IgG fed donors, recipient spleen cells had decreased IFN-γ secretion and IL-12 compared to IgG isotype control treated cells (Table 2). Recipient spinal lymphocytes had decreased IFN-γ secretion compared to IgG isotype control treated cells (Table 2).

 

Table 2

Spleen cells in recipients of TCZ in vitro treated splenic lymphocytes show decreased IFN-γ and IL-12.

tab-2

* p < 0.001; n=16/group.  Results are expressed as pg/ml ± SEM.

There were no significant changes in IL-2, IL-4, IL-6, IL-10, IL-13, IL-17 or TNF-α (data not shown).

 

CONCLUSIONS:

Ingested (orally administered) TCZ can inhibit clinical disease, CNS inflammation, decrease pro-inflammatory Th1-like cytokines and increase Th2-like anti-inflammatory cytokines. Future experimental work will explore the effect of oral in vivo and in vitro anti-IL-6 antibody on PP CD11b+ lymphocyte suppressive capacity.  Future human trials using oral TCZ will examine absorption, effect on serum IL-6 levels, potential toxicity and immunological effects of this novel use of a monoclonal antibody for the treatment of another autoimmune disease.

 

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