TL1A (TNFSF15) regulates the development of chronic colitis by modulating both T-helper 1 and T-helper 17 activation

Abstract

Background & aims: TL1A is a tumor necrosis factor-like molecule that mediates a strong costimulation of T-helper (T(H)) 1 cells. Expression of TL1A is increased in the mucosa of Crohn's disease patients and murine models of ileitis. The aim of this study was to determine the possible role of TL1A in chronic intestinal inflammation.

Methods: We used dextran sodium sulfate (DSS)-induced chronic colitis to investigate the effects of TL1A on the development of colitis. The cytokine profile in the gut-associated lymphoid tissue (GALT) was measured. Neutralizing anti-TL1A antibodies were injected intraperitoneally into DSS-induced chronic colitis and G protein alphai2(-/-) T-cell transfer colitis models. Severity of colitis was evaluated by body weight, colon length, histology, and cytokine production.

Results: DSS-induced chronic colitis was characterized by the infiltration of CD4(+) T cells. TL1A, death receptor 3, interferon (IFN)-gamma, and interleukin (IL)-17 were increased significantly in GALT of DSS-treated mice. TL1A up-regulated both IFN-gamma production from T(H)1 cells and IL-17 production from T(H)17 cells in GALT CD4(+) T cells. Furthermore, IFN-gamma and IL-17 production from CD4(+) T cells, induced by IL-12 and IL-23 respectively, was enhanced synergistically by combination with TL1A. Anti-TL1A antibody prevented chronic colitis and attenuated established colitis by down-regulation of both T(H)1 and T(H)17 activation.

Conclusions: Our results reveal that TL1A is an important modulator in the development of chronic mucosal inflammation by enhancing T(H)1 and T(H)17 effector functions. The central role of TL1A represents an attractive, novel therapeutic target for the treatment of Crohn's disease patients.

Figure 1. Development of DSS-induced chronic colitis

Chronic colitis induced by four cycles of DSS was evaluated and compared with untreated mice (n=7 per group). All data represent the mean ± SD. (A) Body weight as a percentage of the initial weight at day 1 are shown. (B) Colon length from cecum to rectum. (C) Tsotal numbers of mononuclear cells in GALT. (D) Cellular composition of MLN and LP cells was analyzed by flow cytometry and expressed as percentage of the whole cell population. (E) Cytokine mRNA expression was determined in MLN and colon by real-time PCR. Data were normalized to the expression of β-actin mRNA. (F) Mononuclear cells from GALT were cultured with or without anti-CD3ε and anti-CD28 Abs for IFN-γ and IL-17 and with or without LPS for IL-12 and IL-23. Cytokine productions were measured by ELISA.

Figure 1. Development of DSS-induced chronic colitis

Chronic colitis induced by four cycles of DSS was evaluated and compared with untreated mice (n=7 per group). All data represent the mean ± SD. (A) Body weight as a percentage of the initial weight at day 1 are shown. (B) Colon length from cecum to rectum. (C) Tsotal numbers of mononuclear cells in GALT. (D) Cellular composition of MLN and LP cells was analyzed by flow cytometry and expressed as percentage of the whole cell population. (E) Cytokine mRNA expression was determined in MLN and colon by real-time PCR. Data were normalized to the expression of β-actin mRNA. (F) Mononuclear cells from GALT were cultured with or without anti-CD3ε and anti-CD28 Abs for IFN-γ and IL-17 and with or without LPS for IL-12 and IL-23. Cytokine productions were measured by ELISA.

Figure 1. Development of DSS-induced chronic colitis

Chronic colitis induced by four cycles of DSS was evaluated and compared with untreated mice (n=7 per group). All data represent the mean ± SD. (A) Body weight as a percentage of the initial weight at day 1 are shown. (B) Colon length from cecum to rectum. (C) Tsotal numbers of mononuclear cells in GALT. (D) Cellular composition of MLN and LP cells was analyzed by flow cytometry and expressed as percentage of the whole cell population. (E) Cytokine mRNA expression was determined in MLN and colon by real-time PCR. Data were normalized to the expression of β-actin mRNA. (F) Mononuclear cells from GALT were cultured with or without anti-CD3ε and anti-CD28 Abs for IFN-γ and IL-17 and with or without LPS for IL-12 and IL-23. Cytokine productions were measured by ELISA.

Figure 1. Development of DSS-induced chronic colitis

Chronic colitis induced by four cycles of DSS was evaluated and compared with untreated mice (n=7 per group). All data represent the mean ± SD. (A) Body weight as a percentage of the initial weight at day 1 are shown. (B) Colon length from cecum to rectum. (C) Tsotal numbers of mononuclear cells in GALT. (D) Cellular composition of MLN and LP cells was analyzed by flow cytometry and expressed as percentage of the whole cell population. (E) Cytokine mRNA expression was determined in MLN and colon by real-time PCR. Data were normalized to the expression of β-actin mRNA. (F) Mononuclear cells from GALT were cultured with or without anti-CD3ε and anti-CD28 Abs for IFN-γ and IL-17 and with or without LPS for IL-12 and IL-23. Cytokine productions were measured by ELISA.

Figure 1. Development of DSS-induced chronic colitis

Chronic colitis induced by four cycles of DSS was evaluated and compared with untreated mice (n=7 per group). All data represent the mean ± SD. (A) Body weight as a percentage of the initial weight at day 1 are shown. (B) Colon length from cecum to rectum. (C) Tsotal numbers of mononuclear cells in GALT. (D) Cellular composition of MLN and LP cells was analyzed by flow cytometry and expressed as percentage of the whole cell population. (E) Cytokine mRNA expression was determined in MLN and colon by real-time PCR. Data were normalized to the expression of β-actin mRNA. (F) Mononuclear cells from GALT were cultured with or without anti-CD3ε and anti-CD28 Abs for IFN-γ and IL-17 and with or without LPS for IL-12 and IL-23. Cytokine productions were measured by ELISA.

Figure 1. Development of DSS-induced chronic colitis

Chronic colitis induced by four cycles of DSS was evaluated and compared with untreated mice (n=7 per group). All data represent the mean ± SD. (A) Body weight as a percentage of the initial weight at day 1 are shown. (B) Colon length from cecum to rectum. (C) Tsotal numbers of mononuclear cells in GALT. (D) Cellular composition of MLN and LP cells was analyzed by flow cytometry and expressed as percentage of the whole cell population. (E) Cytokine mRNA expression was determined in MLN and colon by real-time PCR. Data were normalized to the expression of β-actin mRNA. (F) Mononuclear cells from GALT were cultured with or without anti-CD3ε and anti-CD28 Abs for IFN-γ and IL-17 and with or without LPS for IL-12 and IL-23. Cytokine productions were measured by ELISA.

Figure 2. TL1A and DR3 expression are up-regulated in MLN and colon during chronic DSS-induced colitis

(A) TL1A and DR3 mRNA expression were determined in MLN and colon by real-time PCR (n=5 per group). Data were normalized to the expression of β-actin mRNA. (B) Left panel: Dot plot of FACS staining for CD11c and MHC class II of MLN of DSS-treated mice. Right panel: Histogram plot shows TL1A expression of CD11c^high MHC class II⁺ gated cells derived from DSS-treated mice (bold line) or untreated mice (shaded area). (C) CD4⁺ T cells from GALT were cultured with or without TL1A. IFN-γ and IL-17 production were measured by ELISA (n=5 per group).

Figure 2. TL1A and DR3 expression are up-regulated in MLN and colon during chronic DSS-induced colitis

(A) TL1A and DR3 mRNA expression were determined in MLN and colon by real-time PCR (n=5 per group). Data were normalized to the expression of β-actin mRNA. (B) Left panel: Dot plot of FACS staining for CD11c and MHC class II of MLN of DSS-treated mice. Right panel: Histogram plot shows TL1A expression of CD11c^high MHC class II⁺ gated cells derived from DSS-treated mice (bold line) or untreated mice (shaded area). (C) CD4⁺ T cells from GALT were cultured with or without TL1A. IFN-γ and IL-17 production were measured by ELISA (n=5 per group).

Figure 2. TL1A and DR3 expression are up-regulated in MLN and colon during chronic DSS-induced colitis

(A) TL1A and DR3 mRNA expression were determined in MLN and colon by real-time PCR (n=5 per group). Data were normalized to the expression of β-actin mRNA. (B) Left panel: Dot plot of FACS staining for CD11c and MHC class II of MLN of DSS-treated mice. Right panel: Histogram plot shows TL1A expression of CD11c^high MHC class II⁺ gated cells derived from DSS-treated mice (bold line) or untreated mice (shaded area). (C) CD4⁺ T cells from GALT were cultured with or without TL1A. IFN-γ and IL-17 production were measured by ELISA (n=5 per group).

Figure 3. TL1A synergizes with IL-12 or IL-23 in the development of a T_H1 or T_H17 response during chronic colitis

CD4⁺ T cells from GALT of untreated or DSS-treated mice were cultured with IL-12 or IL-23 with or without the additsion of TL1A (10 ng/ml) for 72 h. (A) IFN-γ and IL-17 production were measured by ELISA (n=5 per group). Data presented are means ± SD. (B) FACS analysis of intracellular IFN-γ and IL-17 production by CD4⁺ T cell isolated from the LP of DSS-treated mice. One representative experiment out of 3 independent experiments is shown. (C) IFN-γ and IL-17 production in LP of DSS-treated mice was measured by ELISA (n=5 per group). (D) IL-6 production from GALT stimulated with or without anti-CD3ε and anti-CD28 was measured by ELISA. (E) IL-6 production from GALT CD4⁺ T cells stimulated with or without TL1A. (F) IL-6 production from GALT CD4⁺ T cells of DSS-treated mice stimulated with IL-12 or IL-23 with or without the addition of TL1A.

Figure 3. TL1A synergizes with IL-12 or IL-23 in the development of a T_H1 or T_H17 response during chronic colitis

CD4⁺ T cells from GALT of untreated or DSS-treated mice were cultured with IL-12 or IL-23 with or without the additsion of TL1A (10 ng/ml) for 72 h. (A) IFN-γ and IL-17 production were measured by ELISA (n=5 per group). Data presented are means ± SD. (B) FACS analysis of intracellular IFN-γ and IL-17 production by CD4⁺ T cell isolated from the LP of DSS-treated mice. One representative experiment out of 3 independent experiments is shown. (C) IFN-γ and IL-17 production in LP of DSS-treated mice was measured by ELISA (n=5 per group). (D) IL-6 production from GALT stimulated with or without anti-CD3ε and anti-CD28 was measured by ELISA. (E) IL-6 production from GALT CD4⁺ T cells stimulated with or without TL1A. (F) IL-6 production from GALT CD4⁺ T cells of DSS-treated mice stimulated with IL-12 or IL-23 with or without the addition of TL1A.

Figure 3. TL1A synergizes with IL-12 or IL-23 in the development of a T_H1 or T_H17 response during chronic colitis

CD4⁺ T cells from GALT of untreated or DSS-treated mice were cultured with IL-12 or IL-23 with or without the additsion of TL1A (10 ng/ml) for 72 h. (A) IFN-γ and IL-17 production were measured by ELISA (n=5 per group). Data presented are means ± SD. (B) FACS analysis of intracellular IFN-γ and IL-17 production by CD4⁺ T cell isolated from the LP of DSS-treated mice. One representative experiment out of 3 independent experiments is shown. (C) IFN-γ and IL-17 production in LP of DSS-treated mice was measured by ELISA (n=5 per group). (D) IL-6 production from GALT stimulated with or without anti-CD3ε and anti-CD28 was measured by ELISA. (E) IL-6 production from GALT CD4⁺ T cells stimulated with or without TL1A. (F) IL-6 production from GALT CD4⁺ T cells of DSS-treated mice stimulated with IL-12 or IL-23 with or without the addition of TL1A.

Figure 3. TL1A synergizes with IL-12 or IL-23 in the development of a T_H1 or T_H17 response during chronic colitis

CD4⁺ T cells from GALT of untreated or DSS-treated mice were cultured with IL-12 or IL-23 with or without the additsion of TL1A (10 ng/ml) for 72 h. (A) IFN-γ and IL-17 production were measured by ELISA (n=5 per group). Data presented are means ± SD. (B) FACS analysis of intracellular IFN-γ and IL-17 production by CD4⁺ T cell isolated from the LP of DSS-treated mice. One representative experiment out of 3 independent experiments is shown. (C) IFN-γ and IL-17 production in LP of DSS-treated mice was measured by ELISA (n=5 per group). (D) IL-6 production from GALT stimulated with or without anti-CD3ε and anti-CD28 was measured by ELISA. (E) IL-6 production from GALT CD4⁺ T cells stimulated with or without TL1A. (F) IL-6 production from GALT CD4⁺ T cells of DSS-treated mice stimulated with IL-12 or IL-23 with or without the addition of TL1A.

Figure 3. TL1A synergizes with IL-12 or IL-23 in the development of a T_H1 or T_H17 response during chronic colitis

CD4⁺ T cells from GALT of untreated or DSS-treated mice were cultured with IL-12 or IL-23 with or without the additsion of TL1A (10 ng/ml) for 72 h. (A) IFN-γ and IL-17 production were measured by ELISA (n=5 per group). Data presented are means ± SD. (B) FACS analysis of intracellular IFN-γ and IL-17 production by CD4⁺ T cell isolated from the LP of DSS-treated mice. One representative experiment out of 3 independent experiments is shown. (C) IFN-γ and IL-17 production in LP of DSS-treated mice was measured by ELISA (n=5 per group). (D) IL-6 production from GALT stimulated with or without anti-CD3ε and anti-CD28 was measured by ELISA. (E) IL-6 production from GALT CD4⁺ T cells stimulated with or without TL1A. (F) IL-6 production from GALT CD4⁺ T cells of DSS-treated mice stimulated with IL-12 or IL-23 with or without the addition of TL1A.

Figure 3. TL1A synergizes with IL-12 or IL-23 in the development of a T_H1 or T_H17 response during chronic colitis

CD4⁺ T cells from GALT of untreated or DSS-treated mice were cultured with IL-12 or IL-23 with or without the additsion of TL1A (10 ng/ml) for 72 h. (A) IFN-γ and IL-17 production were measured by ELISA (n=5 per group). Data presented are means ± SD. (B) FACS analysis of intracellular IFN-γ and IL-17 production by CD4⁺ T cell isolated from the LP of DSS-treated mice. One representative experiment out of 3 independent experiments is shown. (C) IFN-γ and IL-17 production in LP of DSS-treated mice was measured by ELISA (n=5 per group). (D) IL-6 production from GALT stimulated with or without anti-CD3ε and anti-CD28 was measured by ELISA. (E) IL-6 production from GALT CD4⁺ T cells stimulated with or without TL1A. (F) IL-6 production from GALT CD4⁺ T cells of DSS-treated mice stimulated with IL-12 or IL-23 with or without the addition of TL1A.

Figure 4. Attenuation of T_H1 and T_H17 responses during DSS-induced chronic colitis by the administration of neutralizing TL1A mAb

500 µg anti- TL1A mAb or control IgG as control were injected i.p. once per week into mice receiving DSS (n=10 per group). (A) Body weights as percentage of initial weight at day 1 were shown. (B) Left panel: Photographs of representative colons from DSS-treated mice receiving anti-TL1A mAb or control are shown. Right panel: Colon length from cecum to rectum. (C) H&E staining of cecum and colon (Original magnification: x 100). (D) Evaluation of histological score. (E) Mononuclear cell numbers of GALT. (F) IFN-γ, L-17, and IL-6 productions from GALT.

Figure 4. Attenuation of T_H1 and T_H17 responses during DSS-induced chronic colitis by the administration of neutralizing TL1A mAb

500 µg anti- TL1A mAb or control IgG as control were injected i.p. once per week into mice receiving DSS (n=10 per group). (A) Body weights as percentage of initial weight at day 1 were shown. (B) Left panel: Photographs of representative colons from DSS-treated mice receiving anti-TL1A mAb or control are shown. Right panel: Colon length from cecum to rectum. (C) H&E staining of cecum and colon (Original magnification: x 100). (D) Evaluation of histological score. (E) Mononuclear cell numbers of GALT. (F) IFN-γ, L-17, and IL-6 productions from GALT.

Figure 4. Attenuation of T_H1 and T_H17 responses during DSS-induced chronic colitis by the administration of neutralizing TL1A mAb

500 µg anti- TL1A mAb or control IgG as control were injected i.p. once per week into mice receiving DSS (n=10 per group). (A) Body weights as percentage of initial weight at day 1 were shown. (B) Left panel: Photographs of representative colons from DSS-treated mice receiving anti-TL1A mAb or control are shown. Right panel: Colon length from cecum to rectum. (C) H&E staining of cecum and colon (Original magnification: x 100). (D) Evaluation of histological score. (E) Mononuclear cell numbers of GALT. (F) IFN-γ, L-17, and IL-6 productions from GALT.

Figure 4. Attenuation of T_H1 and T_H17 responses during DSS-induced chronic colitis by the administration of neutralizing TL1A mAb

500 µg anti- TL1A mAb or control IgG as control were injected i.p. once per week into mice receiving DSS (n=10 per group). (A) Body weights as percentage of initial weight at day 1 were shown. (B) Left panel: Photographs of representative colons from DSS-treated mice receiving anti-TL1A mAb or control are shown. Right panel: Colon length from cecum to rectum. (C) H&E staining of cecum and colon (Original magnification: x 100). (D) Evaluation of histological score. (E) Mononuclear cell numbers of GALT. (F) IFN-γ, L-17, and IL-6 productions from GALT.

Figure 4. Attenuation of T_H1 and T_H17 responses during DSS-induced chronic colitis by the administration of neutralizing TL1A mAb

500 µg anti- TL1A mAb or control IgG as control were injected i.p. once per week into mice receiving DSS (n=10 per group). (A) Body weights as percentage of initial weight at day 1 were shown. (B) Left panel: Photographs of representative colons from DSS-treated mice receiving anti-TL1A mAb or control are shown. Right panel: Colon length from cecum to rectum. (C) H&E staining of cecum and colon (Original magnification: x 100). (D) Evaluation of histological score. (E) Mononuclear cell numbers of GALT. (F) IFN-γ, L-17, and IL-6 productions from GALT.

Figure 4. Attenuation of T_H1 and T_H17 responses during DSS-induced chronic colitis by the administration of neutralizing TL1A mAb

500 µg anti- TL1A mAb or control IgG as control were injected i.p. once per week into mice receiving DSS (n=10 per group). (A) Body weights as percentage of initial weight at day 1 were shown. (B) Left panel: Photographs of representative colons from DSS-treated mice receiving anti-TL1A mAb or control are shown. Right panel: Colon length from cecum to rectum. (C) H&E staining of cecum and colon (Original magnification: x 100). (D) Evaluation of histological score. (E) Mononuclear cell numbers of GALT. (F) IFN-γ, L-17, and IL-6 productions from GALT.

Figure 5. Attenuation of T cell-mediated colitis in Gαi2^−/− T cells transferred model by anti-TL1A mAb

(A) Severe T cell-mediated colitis was induced by Gαi2^−/− T cells transferred into RAG^−/− mice. 500 µg anti-TL1A mAb or control IgG i.p. injections twice per week were started at day 1 (n=10 per group). Mice were sacrificed 4 weeks after cell transfer. Upper panel: Photographs of representative ileum and colons from Gαi2^−/− T cells transfer induced colitis receiving anti-TL1A mAb or control IgG are shown. Lower panel: H&E staining of proximal colon (Original magnification: x 100). (B) Disease scores (n=9 and 10 for control IgG and anti-TL1A, respectively). (C) Cytokine productions from GALT were measured by ELISA (n=6 mice per group).

Figure 5. Attenuation of T cell-mediated colitis in Gαi2^−/− T cells transferred model by anti-TL1A mAb

(A) Severe T cell-mediated colitis was induced by Gαi2^−/− T cells transferred into RAG^−/− mice. 500 µg anti-TL1A mAb or control IgG i.p. injections twice per week were started at day 1 (n=10 per group). Mice were sacrificed 4 weeks after cell transfer. Upper panel: Photographs of representative ileum and colons from Gαi2^−/− T cells transfer induced colitis receiving anti-TL1A mAb or control IgG are shown. Lower panel: H&E staining of proximal colon (Original magnification: x 100). (B) Disease scores (n=9 and 10 for control IgG and anti-TL1A, respectively). (C) Cytokine productions from GALT were measured by ELISA (n=6 mice per group).

Figure 5. Attenuation of T cell-mediated colitis in Gαi2^−/− T cells transferred model by anti-TL1A mAb

(A) Severe T cell-mediated colitis was induced by Gαi2^−/− T cells transferred into RAG^−/− mice. 500 µg anti-TL1A mAb or control IgG i.p. injections twice per week were started at day 1 (n=10 per group). Mice were sacrificed 4 weeks after cell transfer. Upper panel: Photographs of representative ileum and colons from Gαi2^−/− T cells transfer induced colitis receiving anti-TL1A mAb or control IgG are shown. Lower panel: H&E staining of proximal colon (Original magnification: x 100). (B) Disease scores (n=9 and 10 for control IgG and anti-TL1A, respectively). (C) Cytokine productions from GALT were measured by ELISA (n=6 mice per group).

Figure 6. Effect of neutralizing TL1A mAb after the development of DSS induced chronic colitis

Treatment with mAb was started after 2 cycles of DSS (n=5 per group). (A) 500 µg anti-TL1A mAb or control IgG i.p. injections twice per week were started at day 15. Body weights as percentage of initial weight at day 1 were shown. (B) Colon length from cecum to rectum. (C) H&E staining of representative colons from DSS-treated mice receiving control IgG (upper panel; Original magnification: x 100) or anti- TL1A mAb (lower panel; x 200) or are shown. (D) Evaluation of histological score. (E) Mononuclear cell numbers (F) Cytokine production from GALT were measured by ELISA.

Figure 6. Effect of neutralizing TL1A mAb after the development of DSS induced chronic colitis

Treatment with mAb was started after 2 cycles of DSS (n=5 per group). (A) 500 µg anti-TL1A mAb or control IgG i.p. injections twice per week were started at day 15. Body weights as percentage of initial weight at day 1 were shown. (B) Colon length from cecum to rectum. (C) H&E staining of representative colons from DSS-treated mice receiving control IgG (upper panel; Original magnification: x 100) or anti- TL1A mAb (lower panel; x 200) or are shown. (D) Evaluation of histological score. (E) Mononuclear cell numbers (F) Cytokine production from GALT were measured by ELISA.

Figure 6. Effect of neutralizing TL1A mAb after the development of DSS induced chronic colitis

Treatment with mAb was started after 2 cycles of DSS (n=5 per group). (A) 500 µg anti-TL1A mAb or control IgG i.p. injections twice per week were started at day 15. Body weights as percentage of initial weight at day 1 were shown. (B) Colon length from cecum to rectum. (C) H&E staining of representative colons from DSS-treated mice receiving control IgG (upper panel; Original magnification: x 100) or anti- TL1A mAb (lower panel; x 200) or are shown. (D) Evaluation of histological score. (E) Mononuclear cell numbers (F) Cytokine production from GALT were measured by ELISA.

Figure 6. Effect of neutralizing TL1A mAb after the development of DSS induced chronic colitis

Treatment with mAb was started after 2 cycles of DSS (n=5 per group). (A) 500 µg anti-TL1A mAb or control IgG i.p. injections twice per week were started at day 15. Body weights as percentage of initial weight at day 1 were shown. (B) Colon length from cecum to rectum. (C) H&E staining of representative colons from DSS-treated mice receiving control IgG (upper panel; Original magnification: x 100) or anti- TL1A mAb (lower panel; x 200) or are shown. (D) Evaluation of histological score. (E) Mononuclear cell numbers (F) Cytokine production from GALT were measured by ELISA.

Figure 6. Effect of neutralizing TL1A mAb after the development of DSS induced chronic colitis

Treatment with mAb was started after 2 cycles of DSS (n=5 per group). (A) 500 µg anti-TL1A mAb or control IgG i.p. injections twice per week were started at day 15. Body weights as percentage of initial weight at day 1 were shown. (B) Colon length from cecum to rectum. (C) H&E staining of representative colons from DSS-treated mice receiving control IgG (upper panel; Original magnification: x 100) or anti- TL1A mAb (lower panel; x 200) or are shown. (D) Evaluation of histological score. (E) Mononuclear cell numbers (F) Cytokine production from GALT were measured by ELISA.

Figure 6. Effect of neutralizing TL1A mAb after the development of DSS induced chronic colitis

Treatment with mAb was started after 2 cycles of DSS (n=5 per group). (A) 500 µg anti-TL1A mAb or control IgG i.p. injections twice per week were started at day 15. Body weights as percentage of initial weight at day 1 were shown. (B) Colon length from cecum to rectum. (C) H&E staining of representative colons from DSS-treated mice receiving control IgG (upper panel; Original magnification: x 100) or anti- TL1A mAb (lower panel; x 200) or are shown. (D) Evaluation of histological score. (E) Mononuclear cell numbers (F) Cytokine production from GALT were measured by ELISA.

Figure 7. Neutralizing IL-23R mAb attenuates DSS-induced chronic colitis

100 µg anti-mouse IL-23R mAb or control IgG were injected i.p. once per week into mice receiving DSS-drinking water (n=5 per group). (A) Body weights as percentage of initial weight at day 1. (B) Colon length and histological scores. 100 µg anti- IL-23R mAb or control IgG i.p. injections twice per week were started at day 15 (n=5 per group). (C) Body weights as percentage of initial weight at day 1 were shown. (D) Colon length and histological score. (E) Cells from MLN and LP from mice receiving control IgG, or anti-IL-23R mAb from day 15 were cultured with or without anti-CD3ε and anti-CD28 Ab for 72 h. Cytokine productions were measured by ELISA (n=5 per group).

Figure 7. Neutralizing IL-23R mAb attenuates DSS-induced chronic colitis

100 µg anti-mouse IL-23R mAb or control IgG were injected i.p. once per week into mice receiving DSS-drinking water (n=5 per group). (A) Body weights as percentage of initial weight at day 1. (B) Colon length and histological scores. 100 µg anti- IL-23R mAb or control IgG i.p. injections twice per week were started at day 15 (n=5 per group). (C) Body weights as percentage of initial weight at day 1 were shown. (D) Colon length and histological score. (E) Cells from MLN and LP from mice receiving control IgG, or anti-IL-23R mAb from day 15 were cultured with or without anti-CD3ε and anti-CD28 Ab for 72 h. Cytokine productions were measured by ELISA (n=5 per group).

Figure 7. Neutralizing IL-23R mAb attenuates DSS-induced chronic colitis

100 µg anti-mouse IL-23R mAb or control IgG were injected i.p. once per week into mice receiving DSS-drinking water (n=5 per group). (A) Body weights as percentage of initial weight at day 1. (B) Colon length and histological scores. 100 µg anti- IL-23R mAb or control IgG i.p. injections twice per week were started at day 15 (n=5 per group). (C) Body weights as percentage of initial weight at day 1 were shown. (D) Colon length and histological score. (E) Cells from MLN and LP from mice receiving control IgG, or anti-IL-23R mAb from day 15 were cultured with or without anti-CD3ε and anti-CD28 Ab for 72 h. Cytokine productions were measured by ELISA (n=5 per group).

Figure 7. Neutralizing IL-23R mAb attenuates DSS-induced chronic colitis

100 µg anti-mouse IL-23R mAb or control IgG were injected i.p. once per week into mice receiving DSS-drinking water (n=5 per group). (A) Body weights as percentage of initial weight at day 1. (B) Colon length and histological scores. 100 µg anti- IL-23R mAb or control IgG i.p. injections twice per week were started at day 15 (n=5 per group). (C) Body weights as percentage of initial weight at day 1 were shown. (D) Colon length and histological score. (E) Cells from MLN and LP from mice receiving control IgG, or anti-IL-23R mAb from day 15 were cultured with or without anti-CD3ε and anti-CD28 Ab for 72 h. Cytokine productions were measured by ELISA (n=5 per group).

Figure 7. Neutralizing IL-23R mAb attenuates DSS-induced chronic colitis

100 µg anti-mouse IL-23R mAb or control IgG were injected i.p. once per week into mice receiving DSS-drinking water (n=5 per group). (A) Body weights as percentage of initial weight at day 1. (B) Colon length and histological scores. 100 µg anti- IL-23R mAb or control IgG i.p. injections twice per week were started at day 15 (n=5 per group). (C) Body weights as percentage of initial weight at day 1 were shown. (D) Colon length and histological score. (E) Cells from MLN and LP from mice receiving control IgG, or anti-IL-23R mAb from day 15 were cultured with or without anti-CD3ε and anti-CD28 Ab for 72 h. Cytokine productions were measured by ELISA (n=5 per group).

Figure 8. TL1A plays a pivotal role in the development of T_H1 and T_H17 responses during chronic colitis

(A) During chronic colitis, the integrity of the intestinal epithelial barrier is compromised allowing commensal bacteria to enter LP where they interact with APC present (1). Stimulation of APC, LP tissue macrophages or DC, by commensal bacteria leads to an up-regulation of TL1A (2). APC also secrete IL-12 and IL-23 upon encountering commensal bacteria. TL1A synergistically enhances the potential of IL-12 or IL-23 to induce IFN-γ or IL-17/IL-6 secretion by T_H1 or T_H17 cells, respectively (3). Overwhelming production of these cytokines leads to exacerbation of chronic intestinal inflammation (4). (B) Administration of neutralizing TL1A antibodies during chronic inflammation diminishes the secretion of IFN-γ, IL-17 and IL-6 by T_H1 or T_H17 cells, respectively (5). Thus, blocking TL1A leads to attenuation of chronic inflammation while maintaining the ability to clear pathogenic bacteria (6).