Role of T helper/inducer cells as well as natural killer cells in resistance to Trypanosoma cruzi infection.
T lymphocytes provide a major line of defence against many protozoan parasites. The aim of this work was to determine the role of T-cell helper/inducer subset (T h/i) in the resistance to Trypanosoma cruzi in a murine model. The importance of natural killer (NK) cells in the resistance to the parasite was also evaluated. BALB/c and C57BL/6 mice were injected with either monoclonal antibodies against L3T4, Thy 1.2, NK1.1, or with a polyclonal rabbit antiserum against NK cells (anti-asialo GM-1). The effect of in vivo administration of these antibodies was tested in separate functional assays. After antibody treatment, mice were infected with a low dose of T. cruzi in the bloodstream form. Mice depleted of, or reduced in T, T h/i, or NK cell activity all developed higher parasitaemia and had higher mortality than their control counterparts. Mice injected with anti-L3T4 monoclonal antibodies were unable to generate a specific antibody response to the parasite. Treatment of mice with alpha/beta interferon, which is known to boost NK cell activity, resulted in an enhanced resistance to the parasite. Our data indicate that T h/i cells as well as NK cells are of vital importance in controlling parasitaemia and reducing mortality in T. cruzi-infected mice. Finally, we also demonstrate that the production of antibodies specific for T. cruzi is strictly T helper cell-dependent.
Rottenberg
M
M
Department of Immunology, Karolinska Institute, Stockholm, Sweden.
Cardoni
R L
RL
Andersson
R
R
Segura
E L
EL
Orn
A
A
D000818:Animals; D014355:Chagas Disease / Q000276:immunology*; D007113:Immunity, Innate; D007372:Interferons / Q000494:pharmacology; D007518:Isoantibodies / Q000276:immunology; D007694:Killer Cells, Natural / Q000276:immunology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
D007518:Isoantibodies; C035678:anti-Thy antibody; D007372:Interferons