Human BDCA-1-Positive Blood Dendritic Cells Differentiate into Phenotypically Distinct Immature and Mature Populations in the Absence of Exogenous Maturational Stimuli: Differentiation Failure in HIV Infection

Abstract

Current immunological opinion holds that myeloid dendritic cell (mDC) precursors migrate from the blood to the tissues, where they differentiate into immature dermal- and Langerhans-type dendritic cells (DC). Tissue DC require appropriate signals from pathogens or inflammatory cytokines to mature and migrate to secondary lymphoid tissue. We show that purified blood mDC cultured in vitro with GM-CSF and IL-4, but in the absence of added exogenous maturation stimuli, rapidly differentiate into two maturational and phenotypically distinct populations. The major population resembles immature dermal DC, being positive for CD11b, CD1a, and DC-specific ICAM-3-grabbing nonintegrin. They express moderate levels of MHC class II and low levels of costimulatory molecules. The second population is CD11b−/low and lacks CD1a and DC-specific ICAM-3-grabbing nonintegrin but expresses high levels of MHC class II and costimulatory molecules. Expression of CCR7 on the CD11b−/low population and absence on the CD11b+ cells further supports the view that these cells are mature and immature, respectively. Differentiation into mature and immature populations was not blocked by polymyxin B, an inhibitor of LPS. Neither population labeled for Langerin, E-cadherin, or CCR6 molecules expressed by Langerhans cells. Stimulation of 48-h cultured DC with LPS, CD40L, or poly(I:C) caused little increase in MHC or costimulatory molecule expression in the CD11b−/low DC but caused up-regulated expression in the CD11b+ cells. In HIV-infected individuals, there was a marked decrease in the viability of cultured blood mDC, a failure to differentiate into the two populations described for normal donors, and an impaired ability to stimulate T cell proliferation.

Activin-A: a novel dendritic cell–derived cytokine that potently attenuates CD40 ligand–specific cytokine and chemokine production

“…Low levels of activin-A were detected by 4 hours after stimulation reaching by 24 hours to between 0.4 and 1 ng/mL ( Figure 2D). Consistent with the fact that these cells spontaneously mature on in vitro culture 50 (and our unpublished data), it was found that unstimulated CD1c ϩ PBDCs produced equivalent levels of activin-A to those detected after stimulation with the various classes of stimuli tested ( Figure 2D). Furthermore, CD1c ϩ PBDCs produced similar levels of activin-A (with or without stimuli) irrespective of culture in serum-containing or serum-free media ( Figure 2E).…”

Activity of different vaccine-associated promoter elements in human dendritic cells

“…Our previous studies have shown that after culture for 2 days in the presence of GM-CSF and IL-4, blood mDC differentiate and acquire markers such as CD1a and DC-SIGN, characteristic of tissue DC [24]. Transduction of 48 h cultured mDC led to higher levels of eGFP expression, with and without CD40L stimulation, than freshly isolated cells for all three vectors.…”

Processing and cross-presentation of individual HLA-A, -B, or -C epitopes from NY-ESO-1 or an HLA-A epitope for Melan-A differ according to the mode of antigen delivery

“…In this regard, CD1c ϩ DCs rapidly and spontaneously mature in vitro. 44 As a result, CD1c ϩ DCs may lose the capacity to internalize and process antigen compared with MoDCs. The combined effects of reduced antigen uptake capacity and limiting intracellular colocalization of antigen and adjuvant may explain the differing efficiencies of cross-presentation between these 2 DC subsets.…”