The receptor DEC-205 expressed by dendritic cells and thymic epithelial cells is involved in antigen processing

Abstract

Dendritic cells and thymic epithelial cells perform important immunoregulatory functions by presenting antigens in the form of peptides bound to cell-surface major histocompatibility complex (MHC) molecules to T cells. Whereas B cells are known to present specific antigens efficiently through their surface immunoglobins, a comparable mechanism for the capture and efficient presentation of diverse antigens by dendritic cells and thymic epithelial cells has not previously been described. We show here that their antigen-presentation function is associated with the high-level expression of DEC-205, an integral membrane protein homologous to the macrophage mannose receptor and related receptors which are able to bind carbohydrates and mediate endocytosis. DEC-205 is rapidly taken up by means of coated pits and vesicles, and is delivered to a multivesicular endosomal compartment that resembles the MHC class II-containing vesicles implicated in antigen presentation. Rabbit antibodies that bind DEC-205 are presented to reactive T-cell hybridomas 100-fold more efficiently than rabbit antibodies that do not bind DEC-205. Thus DEC-205 is a novel endocytic receptor that can be used by dendritic cells and thymic epithelial cells to direct captured antigens from the extracellular space to a specialized antigen-processing compartment.

C‐reactive protein impairs human CD14+ monocyte‐derived dendritic cell differentiation, maturation and function

“…This 205-kD protein contains C-type lectin domains and is a homologue to the MR CD206. In fact, both the MR [47,48] and DEC-205 [49,50] mediate antigen uptake. CD205 expression on human DC is up-regulated upon maturation, and this endocytic receptor is involved in both antigen uptake and processing.…”

Antibody-targeted vaccines

“…A distinguishing feature of DEC-205 is its highlevel expression on DCs in the T-cell areas of lymphoid organs, suggesting a role in regulating T-cell responses. DEC-205 is internalized by means of coated pits and vesicles, and traffics to endosomal compartments that are rich in MHC class II molecules (Jiang et al, 1995). In contrast, MR expression on DCs is primarily restricted to interstitial DCs such as dermal DCs, and traffics to early endosomes that do not contain MHC class II .…”

Potential therapeutic applications of recombinant, invasive E. coli

“…25 DCs were also identified by their characteristic feint spindle-shaped nucleus and finger-like extensions. Invasive E. coli as a therapeutic delivery vector RJ Critchley et al Figure 10a shows that DCs were not detected in Panc-02 tumours injected with PBS, while they were detected in tumours injected with E. coli BM2710 pGB2Oinv-hly and i.p.…”