Inactivated influenza virus, when presented on dendritic cells, elicits human CD8+ cytolytic T cell responses.

278

249

Dengue virus (DV) infection is a major problem in public health. It can cause fatal diseases such as Dengue hemorrhagic fever and Dengue shock syndrome. Dendritic cells (DC) are professional APCs required for establishing a primary immune response. Here, we investigated the role of human PBMC-derived DC in DV infection. Using different techniques, including plaque assay, flow cytometry analysis, nested RT-PCR, and confocal microscope and electron microscope examinations, we show that DV can enter cultured human DC and produce virus particles. After entrance, DV could be visualized in cystic vesicles, vacuoles, and the endoplasmic reticulum. The DV-infected DC also showed proliferation and hypertrophy of the endoplasmic reticulum as well as the swollen mitochondria. In addition, the DV-stimulated DC could express maturation markers such as B7-1, B7-2, HLA-DR, CD11b, and CD83. Furthermore, the infection of DC by DV induced production of TNF-α and IFN-α, but not IL-6 and IL-12. Although DC underwent spontaneous apoptosis in the absence of feeding cytokines, this process appeared to be delayed after DV infection. Our observations provide important information in understanding the pathogenesis of DV infection.

Section: Engue Viruses (Dv)mentioning

confidence: 99%

Infection of Human Dendritic Cells by Dengue Virus Causes Cell Maturation and Cytokine Production

Wang

Shaio

et al. 2001

278

249

“…ϩ CTL responses (1)(2)(3)(4). Different human and murine DC subsets can efficiently prime in vitro and in vivo class I-restricted CTL responses with a wide range of specificities.…”

Section: Prime In Vivo Mhc Class I-restricted Cd8mentioning

confidence: 99%

NKT Cells Provide Help for Dendritic Cell-Dependent Priming of MHC Class I-Restricted CD8+ T Cells In Vivo

Stober

Jomantaitė

Schirmbeck

et al. 2003

115

105

Dendritic cells (DC) are potent APCs for naive T cells in vivo. This is evident by inducing T cell responses through adoptive DC transfer. Priming specific CTL responses in vivo often requires “help”. We study alternative sources of help in DC-dependent priming of MHC class I-restricted CTL. Priming an anti-viral CTL response in naive B6 mice by adoptive transfer of antigenic peptide-pulsed DC required CD4+ T cell help. CTL priming was facilitated by providing MHC class II-dependent specific help. Furthermore, transfers of MHC class II-deficient pulsed DC into naive, normal hosts, or DC transfers into naive, CD4+ T cell-depleted hosts primed CTL inefficiently. Pretreatment of DC with immune-stimulating oligodeoxynucleotides rendered them more efficient for CD4+ T cell-independent priming of CTL. DC copresenting a Kb-binding antigenic peptide and the CD1d-binding glycolipid α-galactosyl-ceramide efficiently primed CTL in a class II-independent way. To obtain NKT cell-dependent help in CTL priming, the same DC had to present both the peptide and the glycolipid. CTL priming by adoptive DC transfer was largely NK cell-dependent. The requirement for NK cells was only partially overcome by recruiting NKT cell help into DC-dependent CTL priming. NKT cells thus are potent helper cells for DC-dependent CTL priming.

“…DCs were then added in graded doses to constant numbers of purified T cells in 96-or 48-well plates (Costar, Cambridge, MA). After 7 days, the T cells were assayed for cytotoxic activity on a TAP Ϫ/Ϫ , HLA-A*0201 MHC class II-negative T2 cell line (American Type Culture Collection) pulsed with 1 M matrix peptide using a conventional 51 Cr release assay (22). Target cells were labeled with Na 51 CrO 4 as previously described (22).…”

Section: Induction Of Influenza Virus-specific Ctlmentioning

confidence: 99%

“…ϩ and CD4 ϩ T cells were isolated from T cell-enriched fractions by negative selection as previously described (21,22).…”

Section: Bulk Cd8mentioning

confidence: 99%

Requirement of Mature Dendritic Cells for Efficient Activation of Influenza A-Specific Memory CD8+ T Cells

Larsson¹,

Messmer²,

Somersan³

et al. 2000

124

It is critical to identify the developmental stage of dendritic cells (DCs) that is most efficient at inducing CD8+ T cell responses. Immature DCs can be generated from monocytes with GM-CSF and IL-4, while maturation is accomplished by the addition of stimuli such as monocyte-conditioned medium, CD40 ligand, and LPS. We evaluated the ability of human monocytes and immature and mature DCs to induce CD8+ effector responses to influenza virus Ags from resting memory cells. We studied replicating virus, nonreplicating virus, and the HLA-A*0201-restricted influenza matrix protein peptide. Sensitive and quantitative assays were used to measure influenza A-specific immune responses, including MHC class I tetramer binding assays, enzyme-linked immunospot assays for IFN-γ production, and generation of cytotoxic T cells. Mature DCs were demonstrated to be superior to immature DC in eliciting IFN-γ production from CD8+ effector cells. Furthermore, only mature DCs, not immature DCs, could expand and differentiate CTL precursors into cytotoxic effector cells over 7 days. An exception to this was immature DCs infected with live influenza virus, because of the virus’s known maturation effect. Finally, mature DCs pulsed with matrix peptide induced CTLs from highly purified CD8+ T cells without requiring CD4+ T cell help. These differences between DC stages were independent of Ag concentrations or the number of immature DCs. In contrast to DCs, monocytes were markedly inferior or completely ineffective stimulators of T cell immunity. Our data with several qualitatively different assays of the memory CD8+ T cell response suggest that mature cells should be considered as immunotherapeutic adjuvants for Ag delivery.