![Figure 1. IL-17RA signaling in host tissues attenuates GVHD and donor T-cell expansion. (A) Lethally irradiated B6.WT or B6.IL-17RA−/− mice received T-cell replete or TCD splenocytes from G-CSF mobilized BALB/c.WT donors. Survival is represented by Kaplan-Meier analysis: ****P < .0001, BALB/c.WT → B6.WT (red filled circles; n = 21) vs BALB/c.WT → B6.IL-17RA−/− (blue filled squares; n = 17). BALB/c.WT (TCD) → B6.IL-17RA−/− (green open squares; n = 10). Combined data from 3 experiments are shown. (B) Serum cytokine levels over time post-alloSCT (n = 6 per group). B6.WT (red bars) vs B6.IL-17RA−/− (blue bars) recipients: IL-17A, **P = .002 (day 4); GM-CSF, *P = .02 (day 2), **P = .004 (day 4), **P = .009 (day 6); IL-6, **P = .002 (day 2), *P = .04 (day 4); IL-10, *P = .037 (day 2), **P = .002 (day 4); TNF, *P = .037 (day 2), ****P < .0001 (day 4); and IFN-γ, **P = .002 (day 2), **P = .009 (day 4), **P = .009 (day 6). (C) Grafts prepared using BM from BALB/c.WT donors and T cells from BALB/c luciferase mice were transplanted into lethally irradiated B6.WT or B6.IL-17RA−/− recipients (n = 13 per group). Animals were imaged at day 6 post-SCT and the bioluminescence intensity quantified (photons/sec/cm2/sr × 105) (Cii). Data combined from 2 replicate experiments are shown (panel Ci, WT [red bars], IL-17RA−/− [blue bars]). (D) Semiquantitative histopathology of GVHD target organs at day 6 post-alloSCT (SI, colon, lung: n = 9 to 10 per group; TCD groups: n = 4 per group, green bars; liver: n = 5 per group). SI and colon, B6.WT (red bars) vs B6.IL-17RA−/− (blue bars) recipients: ****P < .0001. Data combined from 2 experiments are shown (i). Representative images of the SI are shown (ii). (E) Intestinal barrier integrity as determined by FITC-dextran levels in serum on day 6 after alloSCT. Mice were orally gavaged with 8 mg FITC-dextran after 4 hours without food or water, and serum harvested 4 hours thereafter. Data combined from 2 replicate experiments are shown (n = 8 to 10 per group): B6.WT (red bar) vs B6.IL-17RA−/− (blue bar) recipients; **P = .004. (F) G-CSF mobilized grafts were unseparated, CD4 TCD or CD8 TCD, and transplanted into lethally irradiated B6.WT or B6.IL-17RA−/− recipients (n = 8 per group). Survival is represented by Kaplan-Meier analysis. ****P < .0001, BALB/c unseparated graft into B6.WT (red open square) vs B6.IL-17RA−/− (blue open circle) recipients; ****P < .0001, BALB/c unseparated graft (blue open circles) vs BALB/c CD4 depleted graft (green filled circles) into B6.IL-17RA−/− recipients; **P < .001, BALB/c unseparated graft (blue open circles) vs BALB/c CD8-depleted graft (purple filled triangle) into B6.IL-17RA−/− recipients. All data are presented as mean ± SEM. BLI, bioluminescence intensity; G-CSF, granulocyte CSF; GIT, gastrointestinal tract; mLN, mesenteric lymph node; ND, not detected; ns, not significant; SI, small intestine; TCD, T-cell deplete(d).](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/129/15/10.1182_blood-2016-08-732628/4/blood732628f1.jpeg?Expires=1735834134&Signature=w7WyM2btQhA8hNCy7p9b-7pgxhuJgmFhWeoqxaMxOEyV~mEkrM7XMK7tUnpKluo0sSAiL9xHtFViwit6p2dOp1s4PX~dF3T-sdSW8dA0wlf9ty0rnHbS3IX3JfObSnc70U0trJ4jipQcvQlyfrRv4F8IrnyO9mb2zVWf2ZQ6JnQV4RdUzTMTUgliBVGE5CDJg5oz04oANUR-7LVmHlzZ96~0F~khiiJ8EyJIv0UdP0DJhG-fsag2QNyr3B7~2VWGQxSboQQqN2-7H2~HUrjZbpzCY3QRXvypdFymjofOoe9sA0WVFv1taeow~r9OnzlDwwjIjJyR5GrDxjFvut82Ow__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
IL-17RA signaling in host tissues attenuates GVHD and donor T-cell expansion. (A) Lethally irradiated B6.WT or B6.IL-17RA−/− mice received T-cell replete or TCD splenocytes from G-CSF mobilized BALB/c.WT donors. Survival is represented by Kaplan-Meier analysis: ****P < .0001, BALB/c.WT → B6.WT (red filled circles; n = 21) vs BALB/c.WT → B6.IL-17RA−/− (blue filled squares; n = 17). BALB/c.WT (TCD) → B6.IL-17RA−/− (green open squares; n = 10). Combined data from 3 experiments are shown. (B) Serum cytokine levels over time post-alloSCT (n = 6 per group). B6.WT (red bars) vs B6.IL-17RA−/− (blue bars) recipients: IL-17A, **P = .002 (day 4); GM-CSF, *P = .02 (day 2), **P = .004 (day 4), **P = .009 (day 6); IL-6, **P = .002 (day 2), *P = .04 (day 4); IL-10, *P = .037 (day 2), **P = .002 (day 4); TNF, *P = .037 (day 2), ****P < .0001 (day 4); and IFN-γ, **P = .002 (day 2), **P = .009 (day 4), **P = .009 (day 6). (C) Grafts prepared using BM from BALB/c.WT donors and T cells from BALB/c luciferase mice were transplanted into lethally irradiated B6.WT or B6.IL-17RA−/− recipients (n = 13 per group). Animals were imaged at day 6 post-SCT and the bioluminescence intensity quantified (photons/sec/cm2/sr × 105) (Cii). Data combined from 2 replicate experiments are shown (panel Ci, WT [red bars], IL-17RA−/− [blue bars]). (D) Semiquantitative histopathology of GVHD target organs at day 6 post-alloSCT (SI, colon, lung: n = 9 to 10 per group; TCD groups: n = 4 per group, green bars; liver: n = 5 per group). SI and colon, B6.WT (red bars) vs B6.IL-17RA−/− (blue bars) recipients: ****P < .0001. Data combined from 2 experiments are shown (i). Representative images of the SI are shown (ii). (E) Intestinal barrier integrity as determined by FITC-dextran levels in serum on day 6 after alloSCT. Mice were orally gavaged with 8 mg FITC-dextran after 4 hours without food or water, and serum harvested 4 hours thereafter. Data combined from 2 replicate experiments are shown (n = 8 to 10 per group): B6.WT (red bar) vs B6.IL-17RA−/− (blue bar) recipients; **P = .004. (F) G-CSF mobilized grafts were unseparated, CD4 TCD or CD8 TCD, and transplanted into lethally irradiated B6.WT or B6.IL-17RA−/− recipients (n = 8 per group). Survival is represented by Kaplan-Meier analysis. ****P < .0001, BALB/c unseparated graft into B6.WT (red open square) vs B6.IL-17RA−/− (blue open circle) recipients; ****P < .0001, BALB/c unseparated graft (blue open circles) vs BALB/c CD4 depleted graft (green filled circles) into B6.IL-17RA−/− recipients; **P < .001, BALB/c unseparated graft (blue open circles) vs BALB/c CD8-depleted graft (purple filled triangle) into B6.IL-17RA−/− recipients. All data are presented as mean ± SEM. BLI, bioluminescence intensity; G-CSF, granulocyte CSF; GIT, gastrointestinal tract; mLN, mesenteric lymph node; ND, not detected; ns, not significant; SI, small intestine; TCD, T-cell deplete(d).
