Identification of proliferating dendritic cell precursors in mouse blood

While it has been known that dendritic cells arise from proliferating precursors in situ, it has been difficult to identify progenitors in culture. We find that aggregates of growing dendritic cells develop in cultures of mouse blood that are supplemented with granulocyte/macrophage colony-stimulating factor (GM-CSF) but not other CSFs. The dendritic cell precursor derives from the Ia-negative and nonadherent fraction. The aggregates of developing dendritic cells appear at about 1 wk of culture, with 100 or more such clusters being formed per 106 blood leukocytes. The aggregates can be dislodged and subcultured as expanding clusters that are covered with cells having the motile sheet-like processes (“veils”) of dendritic cells. By about 2 wk, large numbers of single, major histocompatibility complex (MHC) class II-rich dendritic cells begin to be released into the medium. Combined immunoperoxidase and [3H]thymidine autoradiograph, show that the cells that proliferate within the aggregate lack certain antigenic markers that are found on mature dendritic cells. However, in pulse-chase protocols, the [3H]thymidinelabeled progeny exhibit many typical dendritic cell features, including abundant MHC class II and a cytoplasmic granular antigen identified by monodonal antibody 2A1. The progeny dendritic cells are potent stimulators of the mixed leukocyte reaction and can home to the T-dependent areas of lymph node after injection into the footpads. We conclude that mouse blood contains GM-CSF-dependent, proliferating progenitors that give rise to large numbers of dendritic cells with characteristic morphology, mobility, phenotype, and strong T cell stimulatory function

The tissue distribution of the B7-2 costimulator in mice: abundant expression on dendritic cells in situ and during maturation in vitro

Inaba, K., Witmer-Pack, M., Inaba, M., Sakuta, H., Hathcock, K.S., Azuma, M., Yagita, H., Okumura, K., Linsley, P.S., Ikehara, S., Muramatsu, S., Hodes, R.J., and Steinman, R.M. The tissue distribution of the B7-2 costimulator in mice: abundant expression on dendritic cells in situ and during maturation in vitro. J. Exp. Med. 180: 1849-1860, 1994https://digitalcommons.rockefeller.edu/historical-scientific-reports/1037/thumbnail.jp

The function of Ia+ dendritic cells and ia dendritic cell precursors in thymocyte mitogenesis to lectin and lectin plus interleukin i

[No abstract available

The distinct leukocyte integrins of mouse spleen dendritic cells as identified with new hamster monoclonal antibodies

Metlay, J.P., Witmer-Pack, M.D., Agger, R., Crowley, M.T., Lawless, D., and Steinman, R.M. The distinct leukocyte integrins of mouse spleen dendritic cells as identified with new hamster monoclonal antibodies. J. Exp. Med. 171: 1753-1771, 1990https://digitalcommons.rockefeller.edu/historical-scientific-reports/1025/thumbnail.jp

High levels of a major histocompatibility complex II-self peptide complex on dendritic cells from the T cell areas of lymph nodes

T lymphocytes recirculate continually through the T cell areas of peripheral lymph nodes. During each passage, the T cells survey the surface of large dendritic cells (DCs), also known as interdigitating cells. However, these DCs have been difficult to release from the lymph node. By emphasizing the use of calcium-free media, as shown by Vremec et al. (Vremec, D., M. Zorbas, R. Scollay, D. J. Saunders, C.F. Ardavin, L. Wu, and K. Shortman. 1992. J. Exp. Med. 176:47-58.), we have been able to release and enrich DCs from the T cell areas. The DCs express the CD11c leukocyte integrin, the DEC- 205 multilectin receptor for antigen presentation, the intracellular granule antigens which are recognized by monoclonal antibodies M342, 2A1, and MIDC- 8, very high levels of MHC I and MHC II, and abundant accessory molecules such as CD40, CD54, and CD86. When examined with the Y-Ae monoclonal which recognizes complexes formed between I-A(b) and a peptide derived from I-Eα, the T cell area DCs expressed the highest levels. The enriched DCs also stimulated a T-T hybridoma specific for this MHC II-peptide complex, and the hybridoma underwent apoptosis. Therefore DCs within the T cell areas can be isolated. Because they present very high levels of self peptides, these DCs should be considered in the regulation of self reactivity in the periphery

Identification of proliferating dendritic cell precursors in mouse blood

Inaba, K., Steinman, R.M., Witmer-Pack, M., Aya, H., Inaba, M., Sudo, T., Wolpe, S., and Schuler, G. Identification of proliferating dendritic cell precursors in mouse blood. J. Exp. Med. 175: 1157-1167, 1992https://digitalcommons.rockefeller.edu/historical-scientific-reports/1031/thumbnail.jp

HIV-1 selectively infects a subset of nonmaturing BDCA1-positive dendritic cells in human blood

The infection of cultured monocyte-derived dendritic cells (DCs) with HIV-1 involves CD4 and CCR5 receptors, while transmission to T cells is enhanced at least in part by the lectin DC-SIGN/CD209. In the present study, we studied BDCA-1+ myeloid DCs isolated directly from human blood. These cells express CD4 and low levels of CCR5 and CXCR4 coreceptors, but not DC-SIGN. The myeloid DCs replicate two R5 viruses, BaL and YU2, and transfer infection to activated T cells. The virus productively infects a small fraction of the blood DCs that fail to mature in culture, as indicated by the maturation markers CD83 and DC-LAMP/ CD208, and the expression of high CD86 and MHC class II, in contrast to many noninfected DCs. A greater proportion of BDCA-1+ DCs are infected when the virus is pseudotyped with the vesicular stomatitis envelope VSV-G (5-15%), as compared with the RS virus (0.3-3.5%), indicating that HIV-1 coreceptors may limit the susceptibility of DCs to become infected, or the endocytic route of viral entry used by HIV/vesicular stomatitis virus enhances infectivity. When infected and noninfected cells are purified by cell sorting, the former uniformly express HIV p24 gag and are virtually inactive as stimulators of the allogeneic MLR, in contrast to potent stimulation by noninfected DCs from the same cultures. These results point to two roles for a small fraction of blood DCs in HIV-1 pathogenesis: to support productive infection and to evade the direct induction of T cell-mediated immunity

The distinct leukocyte integrins of mouse spleen dendritic cells as identified with new hamster monoclonal antibodies

[No abstract available

Dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin/CD209 is abundant on macrophages in the normal human lymph node and is not required for dendritic cell stimulation of the mixed leukocyte reaction

The C-type lectin dendritic cell-specific ICAM 3-grabbing nonintegrin (DC-SIGN)/CD209 efficiently binds several pathogens, including HIV-1. DC-SIGN is expressed on monocyte-derived DCs in culture, and importantly, it is able to sequester HIV-1 within cells and facilitate transmission of virus to CD4 + T cells. To investigate DC-SIGN function, we have generated new mAbs. We report in this study that these and prior anti-DC-SIGN mAbs primarily label macrophages in the medullary sinuses of noninflamed human lymph node. In contrast, expression is not detected on most DCs in the T cell area, except for occasional cells. We also noted that IL-4 alone can induce expression of DC-SIGN in CD14+ monocytes and circulating blood DCs. However, blockade of DC-SIGN with Abs and DC-SIGN small interfering RNA did not result in a major reduction in the capacity of these DCs to transfer HIV to T cells, confirming significant DC-SIGN-independent mechanisms. The blocking approaches did reduce HIV-1 transmission by DC-SIGN-transfected cells by \u3e90%. DC-SIGN blockade also did not reduce the ability of DCs to stimulate T cell proliferation in the MLR. These results indicate that DC-SIGN has the potential to contribute to macrophage function in normal human lymph node, and that DCs do not require DC-SIGN to transmit HIV or to initiate T cell responses

The Tissue Distribution of the B7-2 Costimulator in Mice: Abundant Expression on Dendritic Cells In Situ and During Maturation In Vitro

B7-2 is a recently discovered, second ligand for the CTLA-4/CD28, T cell signaling system. Using the GL-1 rat monoclonal antibody (mAb), we monitored expression of B7-2 on mouse leukocytes with an emphasis on dendritic cells. By cytofluorography, little or no B7-2 was detected on most cell types isolated from spleen, thymus, peritoneal cavity, skin, marrow, and blood. However, expression of B7-2 could be upregulated in culture. In the case of epidermal and spleen dendritic cells, which become highly immunostimulatory for T cells during a short period of culture, the upregulation of B7-2 was dramatic and did not require added stimuli. Lipopolysaccharide did not upregulate B7-2 levels on dendritic cells, in contrast to macrophages and B cells. By indirect immunolabeling, the level of staining with GL-1 mAb exceeded that seen with rat mAbs to several other surface molecules including intercellular adhesion molecule 1, B7-1, CD44, and CD45, as well as new hamster mAbs to CD40, CD48, and B7-1/CD80. Of these accessory molecules, B7-2 was a major species that increased in culture, implying a key role for B7-2 in the functional maturation of dendritic cells. B7-2 was the main (\u3e90%) CTLA-4 ligand on mouse dendritic cells. When we applied GL-1 to tissue sections of a dozen different organs, clear-cut staining with B7-2 antigen was found in many. B7-2 staining was noted on liver Kupffer cells, interstitial cells of heart and lung, and profiles in the submucosa of the esophagus. B7-2 staining was minimal in the kidney and in the nonlymphoid regions of the gut, and was not observed at all in the brain. In the tongue, only rare dendritic cells in the oral epithelium were B7-2 +, but reactive cells were scattered about the interstitial spaces of the muscle. In all lymphoid tissues, GI-1 strongly stained certain distinct regions that are occupied by dendritic cells and by macrophages. For dendritic cells, these include the thvmic medulla, splenic periarterial sheaths, and lymph node deep cortex; for macrophages, the B7-2-rich regions included the splenic marginal zone and lymph node subcapsular cortex. Splenic B7-2+ cells were accessible to labeling with GL-1 mAb given intravenously. Dendritic cell stimulation of T cells (DNA synthesis) during the mixed leukocyte reaction was significantly (35-65%) blocked by GL-1. The block could be enhanced by adding 1G10 anti-B7-1 or by using CTLA-4 Ig, a ligand for both B7-1 and B7-2. We conclude that B7-2, like other accessory molecules, is expressed by many types of antigen-presenting cells. However, the regulation and extent of B7-2 expression seems to differ among cell types. Dendritic cells express very high levels, in several sites in vivo and after maturation into strong accessory cells in culture