Trypanosoma lewisi: the effect of thymectomy on the production of ablastin and the termination of the parasitaemia in infected rats.
This study investigated the effect of the depletion of T lymphocytes on the production of ablastin and the termination of the parasitaemias in Porton strain rats infected with Trypanosoma lewisi. Weanling rats were thymectomised or sham-thymectomised and then X-irradiated. After allowing 96 days for recovery from these procedures the rats were infected with T. lewisi. The rats were considered to be T lymphocyte depleted if they were unable to mount an antibody response to sheep red blood cells before the infection, a delayed type hypersensitivity response to trypanosomal antigen after they had cleared the infection, and if they succumbed to subsequent challenge with an intracellular bacterial parasite, Salmonella typhimurium C5. The T lymphocyte depleted rats were found to have no macroscopic thymus remnants visible at autopsy. The sham-thymectomised and unoperated control rats retained all the T lymphocyte functions tested for. There was no difference between the control and the T lymphocyte depleted rats in the ability to eliminate the parasite following infection with T. lewisi. Ablastin titres in the serum, measured by a sensitive in vitro assay, were found to be the same in each of the groups of rats tested, regardless of their T lymphocyte status. It is concluded that T lymphocytes are not essential for rats to eliminate a T. lewisi infection, nor for the production of ablastin.
D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology; D006968:Hypersensitivity, Delayed; D007074:Immunoglobulin G / Q000096:biosynthesis*; D008212:Lymphocyte Depletion; D008297:Male; D051381:Rats; D013601:T-Lymphocytes / Q000276:immunology*; D013934:Thymectomy; D014350:Trypanosoma lewisi / Q000276:immunology; D014352:Trypanosomiasis / Q000276:immunology* / Q000469:parasitology
D000953:Antigens, Protozoan; D007074:Immunoglobulin G; C019230:ablastin