CD8+ T Cell Responses following Replication-Defective Adenovirus Serotype 5 Immunization Are Dependent on CD11c+ Dendritic Cells but Show Redundancy in Their Requirement of TLR and Nucleotide-Binding Oligomerization Domain-Like Receptor Signaling

Abstract

Replication-defective adenovirus serotype 5 (rAd5) is the most potent recombinant vector for eliciting CD8 T cell responses in humans. In this study, the innate mechanisms that influence T cell responses following rAd5 immunization were assessed in mice. Using rAd5 expressing enhanced GFP (eGFP-rAd5), we show that rAd5 transfects CD11c+ dendritic cells (DCs) in draining lymph nodes in vivo following s.c. or i.m. immunization. Among distinct DC subsets, eGFP expression was highest in CD11c+CD8−B220− with a lower frequency detected in CD11c+CD8+B220− and CD11c+B220+ plasmacytoid DCs. CD11c+ DCs but not CD11c− cells from mice immunized with rAd5 encoding the SIINFEKL peptide induced proliferation of naive OT-I CD8 T cells. Furthermore, CD11c+CD8+B220− was the most potent DC subset for eliciting naive OT-I CD8 T cell proliferation. Of note, mice with pre-existing immunity to rAd5 had a substantial decrease in eGFP expression in DCs, which was associated with ~2-fold decrease in Th1 and complete inhibition of CD8 responses. Thus, pre-existing rAd5 immunity has a greater influence on CD8 compared with CD4 T cell responses. In terms of how innate cytokines and signaling pathways influenced T cell immunity following rAd5 immunization, we show that the magnitude and quality of CD8 T cell responses are partially dependent on MyD88 but independent of IL-12, type I IFN, apoptosis-associated speck-like protein, nucleotide-binding oligomerization domain-like receptor protein 3, and IL-1. Taken together, these data demonstrate a critical role for CD11c+ DCs for CD8 responses but striking redundancy for innate cytokines and signaling by TLR and nucleotide-binding oligomerization domain-like receptor pathways.

Antigen-Specific T-Cell Responses to a Recombinant Fowlpox Virus Are Dependent on MyD88 and Interleukin-18 and Independent of Toll-Like Receptor 7 (TLR7)- and TLR9-Mediated Innate Immune Recognition

“…Our in vivo studies of FWPV-infected TLR and TLR adaptor knockout mice indicated that only MyD88-deficient mice had impaired T-cell immune responses to the FWPV-encoded antigen, a finding recently reported for adaptive immune responses to the replication-incompetent Ad5 vector (41). Despite the demonstrated importance of TLR7 and TLR9 signaling to the recognition of FWPV by pDCs in vitro, our results indicate that the requirements for the specific T-cell recognition of FWPV-derived antigens are met irrespective of the status of TLR7 and TLR9 signaling in vivo.…”

Epitope Specificity Delimits the Functional Capabilities of Vaccine-Induced CD8 T Cell Populations

“…Vaccinations were conducted using one-time, split-site inoculations of Ad5.Gag.Pol in a total volume of 100 ml. Low-dose vaccination comprised 10 8 PU total in 100 ml, and highdose vaccination comprised 10 10 PU total in 100 ml (33)(34)(35)(36)(37). In all cases, equal 50-ml aliquots of the vaccine were administered s.c. in each footpad.…”

Langerin negative dendritic cells promote potent CD8 + T-cell priming by skin delivery of live adenovirus vaccine microneedle arrays

“…Consistent with previous human adenovirus type 5 (AdHu5) vaccine immunization studies by conventional i.m. injection (15,16), the MAs induced robust IFN-γ and TNF-α-producing CD8 + T cells with low levels of intracellular IL-2 (Fig. 1E), and also high-frequency CD8 + T cells with up-regulation of CD107a that also secreted IFN-γ or TNF-α (Fig.…”