Pulmonary Immunity to Viral Infection: Adenovirus Infection of Lung Dendritic Cells Renders T Cells Nonresponsive to Interleukin-2

In spite of the extensive research in the field of gene therapy, host immune responses continue to be the major barrier in translating basic research to clinical practice. Helper-dependent adenoviral (HD-Ad) vectors show great potential for pulmonary gene therapy, but the knowledge of pulmonary immune responses toward these vectors is very limited. In this study, we show that HD-Ad vectors are potent stimulators of dendritic cell (DC) maturation, thus leading to stimulation of T cell proliferation with ∼6% of naive CD4+ T cells from pulmonary mediastinal lymph node responding to HD-Ad-treated DCs. In contrast to the belief that HD-Ad vectors are unable to prime adaptive immune response, we show for the first time, through in vivo pulmonary studies in mice, that HD-Ad vectors can prime CD4+ and CD8+ T cell responses in the lung at high and substantially low doses. This indicates cross-presentation of HD-Ad-derived epitopes by DCs to prime CD8+ T cell responses. To assess the basis of pulmonary T cell response against HD-Ad vectors, we examined the response of conventional DCs (cDCs) and plasmacytoid DCs (pDCs) in the lung. In response to HD-Ad delivery, there is induction of maturation in both cDC and pDC subsets, but it is the cDCs, not pDCs, that migrate rapidly to draining lymph nodes within the first 2 days after vector delivery to prime adaptive immune response against these vectors. These findings have implications for development of strategies to prevent adaptive immune responses against gene therapy vectors.

Section: Discussioncontrasting

confidence: 55%

Characterization of Pulmonary T Cell Response to Helper-Dependent Adenoviral Vectors following Intranasal Delivery

Kushwah

Cao

2008

“…Although the role of pathogens in the migration of LDCs has previously been reported in several models of viral (43)(44)(45) or Mycobacterium tuberculosis (46,47) infection, we describe for the first time the very rapid kinetics of pathogen migration using LDCs.…”

Section: Discussionmentioning

confidence: 99%

Lung Dendritic Cells Rapidly Mediate Anthrax Spore Entry through the Pulmonary Route

Cleret

Quesnel‐Hellmann

Vallon-Eberhard

et al. 2007

138

121

Inhalational anthrax is a life-threatening infectious disease of considerable concern, especially because anthrax is an emerging bioterrorism agent. The exact mechanisms leading to a severe clinical form through the inhalational route are still unclear, particularly how immobile spores are captured in the alveoli and transported to the lymph nodes in the early steps of infection. We investigated the roles of alveolar macrophages and lung dendritic cells (LDC) in spore migration. We demonstrate that alveolar macrophages are the first cells to phagocytose alveolar spores, and do so within 10 min. However, interstitial LDCs capture spores present in the alveoli within 30 min without crossing the epithelial barrier suggesting a specific mechanism for rapid alveolus sampling by transepithelial extension. We show that interstitial LDCs constitute the cell population that transports spores into the thoracic lymph nodes from within 30 min to 72 h after intranasal infection. Our results demonstrate that LDCs are central to spore transport immediately after infection. The rapid kinetics of pathogen transport may contribute to the clinical features of inhalational anthrax.

“…Liver (14), kidney (50), and lung (51) non-parenchymal cells, were isolated as described. For mDC purification, RBC-depleted NPC or splenocytes were incubated first with biotin-conjugated mAb against NK1.1 and streptavidin microbeads (Miltenyi Biotec), then with anti-plasmacytoid DC Ag (PDCA)-1-conjugated microbeads.…”

Section: Methodsmentioning

confidence: 99%

DAP12 Promotes IRAK-M Expression and IL-10 Production by Liver Myeloid Dendritic Cells and Restrains Their T Cell Allostimulatory Ability

Sumpter

Packiam

Turnquist

et al. 2011

Self Cite

Freshly-isolated hepatic dendritic cells (DC) are comparatively immature, relatively resistant to maturation, and can down-modulate effector T cell responses. Molecular mechanisms that underlie these properties are ill-defined. DNAX-activating protein of 12 kDa (DAP12) is an ITAM-bearing transmembrane adaptor protein, that integrates signals through several receptors, including triggering receptor expressed on myeloid cells (TREM)-1, -2; and CD200R. Notably, DC propagated from DAP12-deficient mice exhibit enhanced maturation in response to TLR ligation. Given the constitutive exposure of liver DC to endotoxin draining from the gut, we hypothesized that DAP12 might regulate liver DC maturation. We show that while DAP12 is expressed by both freshly-isolated liver and spleen myeloid DC, LPS-stimulated liver DC maintain DAP12 mRNA expression at higher levels than splenic DC. Moreover, inhibition of DAP12 expression by liver DC using small interfering (si)RNA, promotes their phenotypic and functional maturation, resulting in enhanced TNFα, IL-6 and IL-12p70 production, reduced secretion of IL-10 and enhanced CD4+ and CD8+ T cell proliferation. Furthermore, DAP12 silencing correlates with decreased STAT3 phosphorylation in mature liver DC, and with diminished expression of the IL-1R-associated kinase (IRAK)-M, a negative regulator of TLR signaling. These findings highlight, for the first time, a regulatory role for DAP12 in hepatic DC maturation, and suggest a mechanism whereby this function may be induced/maintained.