Murine dendritic cell development: Difficulties associated with subset analysis

Dendritic cells (DC) migrate from sites of inflammation to lymph nodes to initiate primary immune responses, but the molecular mechanisms by which DC are replenished in the lungs during ongoing pulmonary inflammation are unknown. To address this question, we analyzed the secondary pulmonary immune response of Ag-primed mice to intratracheal challenge with the particulate T cell-dependent Ag sheep erythrocytes (SRBC). We studied wild-type C57BL/6 mice and syngeneic gene-targeted mice lacking either both endothelial selectins (CD62E and CD62P), or the chemokine receptors CCR2 or CCR6. DC, defined as non-autofluorescent, MHC class II+CD11cmod cells, were detected in blood, enzyme-digested minced lung, and bronchoalveolar lavage fluid using flow cytometry and immunohistology. Compared with control mice, Ag challenge increased the frequency and absolute numbers of DC, peaking at day 1 in peripheral blood (6.5-fold increase in frequency), day 3 in lung mince (20-fold increase in total DC), and day 4 in bronchoalveolar lavage fluid (55-fold increase in total DC). Most lung DC expressed CD11c, CD11b, and low levels of MHC class II, CD40, CD80, and CD86, consistent with an immature myeloid phenotype. DC accumulation depended in part upon CCR2 and CCR6, but not endothelial selectins. Thus, during lung inflammation, immature myeloid DC from the bloodstream replace emigrating immature DC and transiently increase total intrapulmonary APC numbers. Early DC recruitment depends in part on CCR2 to traverse vascular endothelium, plus CCR6 to traverse alveolar epithelium. The recruitment of circulating immature DC represents a potential therapeutic step at which to modulate immunological lung diseases.

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“…CD4, CD8, and the pDC marker B220 were not identified in this population (data not shown). Taken together, this phenotypic pro- (49,50).…”

Section: Accumulated In the Lung In Response To Particulate Agindumentioning

confidence: 66%

CCR2 and CCR6, but Not Endothelial Selectins, Mediate the Accumulation of Immature Dendritic Cells within the Lungs of Mice in Response to Particulate Antigen

Osterholzer

Ames²,

Polak

et al. 2005

The Journal of Immunology

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“…Additionally, two major subtypes of CD11c ϩ DC have been described, plasmacytoid and myeloid DC. Myeloid DC are CD11c ϩ , CD11b ϩ , CD8␣ Ϫ , and B220 Ϫ (2,3,19,80), whereas plasmacytoid DC are CD8␣ ϩ and B220 ϩ and lack expression of costimulatory molecules (2,3,7,13,61,80). In preliminary studies with both naïve and infected mice, less than 3% of lung DC expressed B220 (Wozniak and Levitz, unpublished observations), suggesting that the vast majority of these DC are myeloid DC.…”

Section: Fig 4 Effect Of Infection With C Neoformans On the Percenmentioning

confidence: 99%

In Vivo Role of Dendritic Cells in a Murine Model of Pulmonary Cryptococcosis

2006

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Dendritic cells (DC) have been shown to phagocytose and kill Cryptococcus neoformans in vitro and are believed to be important for inducing protective immunity against this organism. Exposure to C. neoformans occurs mainly by inhalation, and in this study we examined the in vivo interactions of C. neoformans with DC in the lung. Fluorescently labeled live C. neoformans and heat-killed C. neoformans were administered intranasally to C57BL/6 mice. At specific times postinoculation, mice were sacrificed, and lungs were removed. Single-cell suspensions of lung cells were prepared, stained, and analyzed by microscopy and flow cytometry. Within 2 h postinoculation, fluorescently labeled C. neoformans had been internalized by DC, macrophages, and neutrophils in the mouse lung. Additionally, lung DC from mice infected for 7 days showed increased expression of the maturation markers CD80, CD86, and major histocompatibility complex class II. Finally, ex vivo incubation of lung DC from infected mice with Cryptococcus-specific T cells resulted in increased interleukin-2 production compared to the production by DC from naïve mice, suggesting that there was antigenspecific T-cell activation. This study demonstrated that DC in the lung are capable of phagocytosing Cryptococcus in vivo and presenting antigen to C. neoformans-specific T cells ex vivo, suggesting that these cells have roles in innate and adaptive pulmonary defenses against cryptococcosis.

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“…In addition, we observed that SP-D increases antigen presentation of bacterial-derived antigen by bone marrow-derived dendritic cells that subsequently and efficiently activate antigen-restricted T-cell hybridomas (CD4ϩ) to increase secretion of IL-2 (28). Dendritic cells are considered a heterogeneous cell population, and their lineage, origin, and degree of maturation are important determinants of their effect on T cells (29). Studies have also shown differences between bone marrowderived dendritic cells and dendritic cells isolated from the spleen or lymph nodes (30,31).…”

mentioning

confidence: 99%