title: Growth of Theileria annulata and Theileria parva macroschizont-infected bovine cells in immunodeficient mice: effect of irradiation and tumour load on lymphocyte subsets.
abstract: Bovine cells infected with macroschizonts of the protozoan parasites Theileria annulata and Theileria parva formed solid tumours when injected into irradiated Balb/c and irradiated Balb/c nude mice. T. annulata tumours grew more vigorously than T. parva tumours, when initiated with similar doses of infected cells in mice exposed to the same doses of gamma-irradiation. In irradiated Balb/c mice, tumours of both species of parasites began to regress 2-3 weeks after injection of cells but grew without regression in irradiated Balb/c nude mice. Haemorrhage and necrosis of tumours, induced by macrophages and neutrophils, were seen in both mouse strains but were insufficient to cause regression in Balb/c nude mice. Theileria-infected bovine cells failed to establish in C57 beige mice, which lack functional natural killer (NK) cells. Flow cytometry, using monoclonal antibodies to murine leukocyte/lymphocyte antigens, showed that the radiation dose required to allow establishment of T. annulata tumours in Balb/c mice caused a severe depletion of splenic lymphocytes. B cells, helper T and cytotoxic T cells showed differing levels of susceptibility to irradiation. The presence of a tumour promoted the recovery of lymphocyte populations: this recovery was accompanied by destruction of the tumour.
authors.affiliation: Division of Biological Sciences, University of Edinburgh, Scotland, U.K.
authors.forename: A H
authors.initials: AH
authors.lastname: Fell
authors.forename: P M
authors.initials: PM
authors.lastname: Preston
mesh_terms: D000818:Animals; D002417:Cattle; D002460:Cell Line; D005260:Female; D016131:Lymphocyte Subsets / Q000528:radiation effects*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D016796:Theileria annulata / Q000254:growth & development / Q000276:immunology*; D016797:Theileria parva / Q000254:growth & development / Q000276:immunology*; D013801:Theileriasis / Q000276:immunology*