Immunization with a lentivector that targets tumor antigen expression to dendritic cells induces potent CD8+ and CD4+ T-cell responses.
Lopes L., Dewannieux M., Gileadi U., Bailey R., Ikeda Y., Whittaker C., Collin MP., Cerundolo V., Tomihari M., Ariizumi K., Collins MK.
Lentivectors stimulate potent immune responses to antigen transgenes and are being developed as novel genetic vaccines. To improve safety while retaining efficacy, we constructed a lentivector in which transgene expression was restricted to antigen-presenting cells using the mouse dectin-2 gene promoter. This lentivector expressed a green fluorescent protein (GFP) transgene in mouse bone marrow-derived dendritic cell cultures and in human skin-derived Langerhans and dermal dendritic cells. In mice GFP expression was detected in splenic dectin-2(+) cells after intravenous injection and in CD11c(+) dendritic cells in the draining lymph node after subcutaneous injection. A dectin-2 lentivector encoding the human melanoma antigen NY-ESO-1 primed an NY-ESO-1-specific CD8(+) T-cell response in HLA-A2 transgenic mice and stimulated a CD4(+) T-cell response to a newly identified NY-ESO-1 epitope presented by H2 I-A(b). As immunization with the optimal dose of the dectin-2 lentivector was similar to that stimulated by a lentivector containing a strong constitutive viral promoter, targeting antigen expression to dendritic cells can provide a safe and effective vaccine.