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Analyzing the Functions of Mast Cells In Vivo Using 'Mast Cell Knock-in' Mice
Published on: May 27, 2015
Perivascular dendritic cells elicit anaphylaxis by relaying allergens to mast cells via microvesicles
Hae Woong Choi1, Jutamas Suwanpradid2, Il Hwan Kim3
1Department of Pathology, Duke University Medical Center, Durham, NC 27710, USA. haewoong.choi@duke.edu.
Abstract:
Anaphylactic reactions are triggered when allergens enter the blood circulation and activate immunoglobulin E (IgE)-sensitized mast cells (MCs), causing systemic discharge of prestored proinflammatory mediators. As MCs are extravascular, how they perceive circulating allergens remains a conundrum. Here, we describe the existence of a CD301b+ perivascular dendritic cell (DC) subset that continuously samples blood and relays antigens to neighboring MCs, which vigorously degranulate and trigger anaphylaxis. DC antigen transfer involves the active discharge of surface-associated antigens on 0.5- to 1.0-micrometer microvesicles (MVs) generated by vacuolar protein sorting 4 (VPS4). Antigen sharing by DCs is not limited to MCs, as neighboring DCs also acquire antigen-bearing MVs. This capacity of DCs to distribute antigen-bearing MVs to various immune cells in the perivascular space potentiates inflammatory and immune responses to blood-borne antigens.
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