Volume 119, Issue 4, Pages 972-982 (October 2000) Interleukin 16 is up-regulated in Crohn's disease and participates in TNBS colitis in mice  Andrew C. Keates, Ignazio Castagliuolo, William W. Cruickshank, Bosheng Qiu, Kristen O. Arseneau, William Brazer, Ciarán P. Kelly  Gastroenterology  Volume 119, Issue 4, Pages 972-982 (October 2000) DOI: 10.1053/gast.2000.18164 Copyright © 2000 American Gastroenterological Association Terms and Conditions

Fig. 1 Colonic IL-16 mRNA levels are elevated in Crohn's disease and ulcerative colitis. Human colonic tissue samples were obtained from patients undergoing colectomy for ulcerative colitis, Crohn's colitis, and from areas of uninvolved colon from patients undergoing colectomy for colon cancer. Total RNA was isolated from normal colon (n = 10) and colonic tissue from patients with either Crohn's disease (n = 11) or ulcerative colitis (n = 10). RNA was then subjected to semiquantitative reverse transcription and PCR to evaluate steady-state IL-16 mRNA levels. Results are expressed as a ratio to GAPDH mRNA levels in the same tissues. The horizontal bar represents the median value, the box represents the 25th and 75th percentile values, and the vertical bars represent the 5th and 95th percentile values. Gastroenterology 2000 119, 972-982DOI: (10.1053/gast.2000.18164) Copyright © 2000 American Gastroenterological Association Terms and Conditions

Fig. 2 Colonic IL-16 protein levels are increased in Crohn's disease but not in ulcerative colitis. Human colonic tissue samples were obtained from patients undergoing colectomy for ulcerative colitis (n = 7), Crohn's colitis (n = 8), and from areas of uninvolved colon from patients undergoing colectomy for colon cancer (n = 9). Colonic IL-16 protein levels in tissue homogenates were measured by ELISA. Results are expressed as a scatter plot. The mean value in each group is indicated by a horizontal bar. The IL-16 level in colonic tissue from patients with Crohn's disease was significantly increased (P < 0.05) compared with normal colon or ulcerative colitis. Gastroenterology 2000 119, 972-982DOI: (10.1053/gast.2000.18164) Copyright © 2000 American Gastroenterological Association Terms and Conditions

Fig. 3 Anti-human IL-16 mAb therapy protects against TNBS-induced weight loss. Colitis was induced in male C57BL/6 mice using TNBS as described in Materials and Methods. Animals were divided into 5 experimental groups: control (n = 9), vehicle (40% ethanol; n = 13). TNBS alone (n = 13), TNBS + anti-human IL-16 mAb (blocking IgG2A mAb, 1 mg IP, 24 hours before and 24 hours after TNBS; n = 12), and TNBS + isotype control mAb (1 mg IP, 24 hours before and 24 hours after TNBS; n = 4). Animals were killed after 3 days, and changes in body weight were determined. Results are expressed as mean ± SEM. Gastroenterology 2000 119, 972-982DOI: (10.1053/gast.2000.18164) Copyright © 2000 American Gastroenterological Association Terms and Conditions

Fig. 4 Anti-human IL-16 mAb therapy attenuates TNBS-mediated colonic ulceration. (A) Acute colitis was induced in male C57BL/6 mice by TNBS (see Materials and Methods). Animals were divided into 4 experimental groups: control (n = 9), vehicle (40% ethanol; n = 13), TNBS alone (n = 13), and TNBS + anti-human IL-16 mAb (blocking IgG2A mAb, 1 mg IP, 24 hours before and 24 hours after TNBS; n = 12). Animals were killed after 3 days, and the degree of colonic ulceration was determined using a macroscopic damage score. Results are means ± SEM. (B) Acute colitis was induced in male BALB/c mice using TNBS (see Materials and Methods). Animals were divided into 4 experimental groups: control (n = 6), vehicle (n = 4), TNBS alone (n = 13), and TNBS + anti-human IL-16 mAb (24 hours before and 24 hours after TNBS; n = 15). Animals were killed after 3 days, and the degree of colonic ulceration was determined using a macroscopic damage score. Results are means ± SEM. (C) Chronic colitis was induced in male BALB/c mice using TNBS (see Materials and Methods). Animals were divided into 4 experimental groups: control (n = 6), vehicle (n = 5), TNBS alone (n = 6), and TNBS + anti-human IL-16 mAb (24 hours before and 24 hours after the second dose of TNBS; n = 10). Animals were killed 3 days after the second dose of TNBS, and the degree of colonic ulceration was determined using a macroscopic damage score. Results are means ± SEM. Gastroenterology 2000 119, 972-982DOI: (10.1053/gast.2000.18164) Copyright © 2000 American Gastroenterological Association Terms and Conditions

Fig. 5 Anti-human IL-16 mAb therapy reduces colonic MPO content during TNBS colitis. Colitis was induced in male C57BL/6 mice using TNBS as described in Materials and Methods. Animals were divided into 4 experimental groups: control (n = 4), vehicle (n = 8), TNBS alone (n = 8), and TNBS + anti-human IL-16 mAb (blocking IgG2A mAb, 1 mg IP, 24 hours before and 24 hours after TNBS; n = 8). Animals were killed after 3 days, the colons were removed, and the mucosal MPO activity was determined. Results are expressed as mean ± SEM per milligram total protein. Gastroenterology 2000 119, 972-982DOI: (10.1053/gast.2000.18164) Copyright © 2000 American Gastroenterological Association Terms and Conditions

Fig. 6 Effect of anti-human IL-16 mAb treatment on colonic IL-1β and TNF-α levels after TNBS administration. Colitis was induced in male C57BL/6 mice using TNBS as described in Materials and Methods. For measurements of colonic IL-1β levels, animals were divided into 3 experimental groups: control (n = 16), TNBS alone (n = 15), and TNBS + anti-human IL-16 mAb (1 mg IP, 24 hours before and 24 hours after TNBS; n = 9). For measurements of colonic TNF-α levels, animals were divided into 3 experimental groups: control (n = 8), TNBS alone (n = 6), and TNBS + anti-human IL-16 mAb (1 mg IP, 24 hours before and 24 hours after TNBS; n = 5). Animals were killed after 3 days, the colons were removed, and colonic cytokine levels were determined by ELISA. Results are expressed as mean ± SEM per milligram total protein. Gastroenterology 2000 119, 972-982DOI: (10.1053/gast.2000.18164) Copyright © 2000 American Gastroenterological Association Terms and Conditions

Fig. 7 Anti-human IL-16 mAb therapy protects against death after high-dose TNBS administration. In initial experiments, male C57BL/6 mice were divided into 5 experimental groups as described in Figure 1, and colitis was induced as described in Materials and Methods except that the dose of TNBS used was 275–300 mg/kg body wt. High-dose TNBS treatment was associated with an unacceptable level of mortality and was discontinued. Values in parentheses indicate the number of surviving animals compared with the total number of animals 3 days after TNBS administration. Results are expressed as mean mortality rate for each experimental group. Gastroenterology 2000 119, 972-982DOI: (10.1053/gast.2000.18164) Copyright © 2000 American Gastroenterological Association Terms and Conditions