Dendritic cells at a DNA vaccination site express the encoded influenza nucleoprotein and prime MHC class I-restricted cytolytic lymphocytes upon adoptive transfer

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CD8 antigen, DNA vaccine, antigen presenting cell, cell migration, cytotoxic T lymphocyte, dendritic cell, genetic transfection, Influenza virus


Intradermal inoculation of plasmids expressing antigens that contain MHC class I-restricted epitopes leads to the induction of specific CD8+ cytotoxic T lymphocytes (CTL). The role of in situ transfected antigen-presenting cells (APC) in the priming of specific CTL subsequent to intradermal DNA immunization was investigated using a plasmid (NPV1) expressing the nucleoprotein (NP) of influenza virus that contains a nuclear targeting signal and a dominant class I/K(d)-restricted epitope. Inoculation of NPV1 leads to in situ transfection of MHC class II+ and class II- cells, as revealed by the nuclear localization of NP. Between 2 and 3% of MHC class II+ and class II- cells with the ability to migrate out of the epidermis expressed NP. Upon adoptive transfer into naive recipients, class II+ migratory cells recovered from the area inoculated with NP-expressing plasmid were significantly superior regarding the ability to prime virus-specific CTL as compared to MHC class II- cells. Together, these results are consistent with the role of local dendritic cells loaded with antigen in the priming of CTL by intradermal DNA immunization.


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