Adeno-associated virus mediated delivery of Tregitope 167 ameliorates experimental colitis

Figure 3 Adeno associated virus serotype 5 mediated delivery of regulatory T-cell epitope 167 alleviates colonic inflammation as determined at the day of sacrifice. Mice were injected intravenously with either phosphate-buffered saline (PBS) or adeno associated virus (AAV) 5 [cytomegalovirus (CMV) promoter T-cell epitopes (Tregitope) 167]. Ten days after AAV-mediated Tregitope delivery acute colitis was initiated by intra-rectal administration of 1.5 mg trinitrobenzene sulfonate (TNBS) in 40% ethanol followed by a second treatment with TNBS (0.75 mg in 20% ethanol) 8 d later. Control groups consisted of mice not treated by TNBS (healthy control group) and mice treated by TNBS only (diseased control group). Disease progression was assessed by changes in daily body weight as well as macroscopic and microscopic scores on the day of sacrifice. A: Animal body weight change on day 20 upon sacrifice. The values of body weight are expressed as a percentage of body weight on the day of the first TNBS treatment; B: Macroscopic disease score. The disease activity index consist of a combination of body weight loss, loose stool and visible fecal blood scores divided by 3 at the day of sacrifice; C: Assessment of colonic weight upon sacrifice as an index of disease-related intestinal wall thickening; D: Histological grading of colonic colitis scores. The histology damage score was calculated using the following criteria: percentage of area involved, number of follicle aggregates, edema, fibrosis, erosion/ulceration, crypt loss, and infiltration of mononuclear and polymorphonuclear cells. Individual mice are depicted; from the AAV5 (CMV-Tregitope 167) pre-treated group an outliner was removed. Animals were withdrawn from the study when their weight loss was > 25% of their original body weight. Overall for the healthy controls, n = 9; AAV5 (CMV-Tregitope 167) treated, n = 6; diseased controls, n = 6, were included in the analysis. The data were analyzed using a 1 way analysis of variance, followed by Dunn’s post hoc test for multiple comparisons. Data are presented as mean ± SD of all the mice. ^aP < 0.05, ^bP < 0.01 vs PBS (diseased control group).