Intestinal amoebiasis: delayed-type hypersensitivity response in mice.

Delayed-type hypersensitive (DTH) response was evaluated in C3H/HeJ mice intestinally infected with Entamoeba histolytica. Infected and non-infected control mice were challenged with amoebic antigen on day 5, 10, 15, 20, 25, 30, 40, 50, and 60 post-infection. Maximum footpad swelling was observed after 24 hours of the challenge. The E. histolytica-infected mice exhibited a DTH response on day 5, 15, 20, 25, 40 and 60 post-infection. However, on day 10, 30, and 50, such response was similar to that of the non-infected control mice. The mice developed an evident DTH response late in the course of infection (25 days post-infection). The infected mice did not show any alteration to their DTH response against heterologous unrelated antigen (sheep red blood cells), suggesting that cellular anergy was antigen-specific.