Major role for CD8 T cells in the protection against Toxoplasma gondii following dendritic cell vaccination

Parasite Immunol. 2009 Oct;31(10):631-40.

Major role for CD8 T cells in the protection against Toxoplasma gondii following dendritic cell vaccination

Guiton R, Zagani R, Dimier-Poisson I.

Université François Rabelais Tours, INRA, UMR 0483 Université-INRA d'Immunologie Parasitaire et Vaccinologie, Biothérapies anti-infectieuses, IFR 136 agents transmissibles en Infectiologie, UFR des Sciences Pharmaceutiques, Tours, France.

Toxoplasma gondii is the causative agent of toxoplasmosis, a worldwide zoonosis for which an effective vaccine is needed. Vaccination with pulsed dendritic cells is very efficient but their use in a vaccination protocol is unconceivable. Nevertheless, unravelling the induced effector mechanisms is crucial to design new vaccine strategies. We vaccinated CBA/J mice with parasite extract-pulsed dendritic cells, challenged them with T. gondii cysts and carried out in vivo depletion of CD4(+) or CD8(+) T lymphocytes to study the subsequent cellular immune response and protective mechanisms. CD4(+) lymphocytes were poorly implicated either in spleen and mesenteric lymph node (MLN) cytokine secretion or in mice protection. By contrast, the increasing number of intracerebral cysts and depletion of CD8(+) cells were strongly correlated, revealing a prominent role for CD8(+) lymphocytes in the protection of mice. Splenic CD8(+) lymphocytes induce a strong Th1 response controlled by a Th2 response whereas CD8(+) cells from MLNs inhibit both Th1 and Th2 responses. CD8(+) cells are the main effectors following dendritic cell vaccination and Toxoplasma infection while CD4(+) T cells only play a minor role. This contrasts with T. gondii infection which elicits the generation of CD4(+) and CD8(+) T cells that provide protective immunity.

PMID: 19751475 [PubMed - in process]