Perforin and gamma interferon expression are required for CD4+ and CD8+ T-cell-dependent protective immunity against a human parasite, Trypanosoma cruzi, elicited by heterologous plasmid DNA prime-recombinant adenovirus 5 boost vaccination.
A heterologous prime-boost strategy using plasmid DNA, followed by replication-defective recombinant adenovirus 5, is being proposed as a powerful way to elicit CD4(+) and CD8(+) T-cell-mediated protective immunity against intracellular pathogens. We confirmed this concept and furthered existing research by providing evidence that the heterologous prime-boost regimen using the gene encoding amastigote surface protein 2 elicited CD4(+) and CD8(+) T-cell-mediated protective immunity (reduction of acute parasitemia and prolonged survival) against experimental infection with Trypanosoma cruzi. Protective immunity correlated with the presence of in vivo antigen-specific cytotoxic activity prior to challenge. Based on this, our second goal was to determine the outcome of infection after heterologous prime-boost immunization of perforin-deficient mice. These mice were highly susceptible to infection. A detailed analysis of the cell-mediated immune responses in immunized perforin-deficient mice showed an impaired gamma interferon (IFN-gamma) secretion by immune spleen cells upon restimulation in vitro with soluble recombinant antigen. In spite of a normal numeric expansion, specific CD8(+) T cells presented several functional defects detected in vivo (cytotoxicity) and in vitro (simultaneous expression of CD107a/IFN-gamma or IFN-gamma/tumor necrosis factor alpha) paralleled by a decreased expression of CD44 and KLRG-1. Our final goal was to determine the importance of IFN-gamma in the presence of highly cytotoxic T cells. Vaccinated IFN-gamma-deficient mice developed highly cytotoxic cells but failed to develop any protective immunity. Our study thus demonstrated a role for perforin and IFN-gamma in a number of T-cell-mediated effector functions and in the antiparasitic immunity generated by a heterologous plasmid DNA prime-adenovirus boost vaccination strategy.
de Alencar
Bruna C G
BC
Centro Interdisciplinar de Terapia Gênica (CINTERGEN), Universidade Federal de São Paulo-Escola Paulista de Medicina, Rua Mirassol 207, São Paulo, SP 04044-010, Brazil.
Persechini
Pedro M
PM
Haolla
Filipe A
FA
de Oliveira
Gabriel
G
Silverio
Jaline C
JC
Lannes-Vieira
Joseli
J
Machado
Alexandre V
AV
Gazzinelli
Ricardo T
RT
Bruna-Romero
Oscar
O
Rodrigues
Mauricio M
MM
D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D014355:Chagas Disease / Q000517:prevention & control*; D005260:Female; D007117:Immunization, Secondary / Q000379:methods; D007371:Interferon-gamma / Q000172:deficiency / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009439:Neuraminidase / Q000235:genetics / Q000276:immunology; D018512:Parasitemia / Q000517:prevention & control; D052899:Pore Forming Cytotoxic Proteins / Q000172:deficiency / Q000276:immunology*; D016052:Protozoan Vaccines / Q000276:immunology*; D016019:Survival Analysis; D014349:Trypanosoma cruzi / Q000276:immunology*; D014611:Vaccination / Q000379:methods; D019444:Vaccines, DNA / Q000276:immunology; D014614:Vaccines, Synthetic / Q000276:immunology
D052899:Pore Forming Cytotoxic Proteins; D016052:Protozoan Vaccines; D019444:Vaccines, DNA; D014614:Vaccines, Synthetic; C483886:perforin, mouse; D007371:Interferon-gamma; C493236:ASP-2 protein, Trypanosoma cruzi; D009439:Neuraminidase