Oral treatment with Hev b 13 ameliorates experimental colitis in mice

Hev b 13 is an allergenic esterase obtained from the rubber tree Hevea brasiliensis, which has been shown recently to induce human mononuclear cells to release interleukin (IL)-10 in vitro. This immunoregulatory cytokine appears to play an important role in preventing inflammation and mucosal damage in animal models of colitis and in Crohn's disease patients. The aim of this study was to evaluate the therapeutic effect of Hev b 13 in mice with 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced colitis. Two hours following colonic instillation of the haptenizing agent, and daily thereafter for 5 days, Hev b 13 was administered by oral gavage. In mice treated with daily doses of either 0.5 mg/kg or 5.0 mg/kg of Hev b 13, the clinical signs of diarrhoea, rectal prolapse and body weight loss and also histological damage of the distal colon, were reduced significantly, in comparison with water-treated diseased mice. These findings suggest a potent anti-inflammatory activity of Hev b 13; this activity is speculated to be related to its interaction with cells from the immune system.