Showing papers by "Elodie Segura published in 2010"

Reply to Burgdorf et al.: The mannose receptor is not involved in antigen cross-presentation by steady-state dendritic cells

Abstract: We thank Burgdorf et al. for suggesting potential explanations for the few discrepancies between our studies (1, 2). Our collagenase treatment did not prevent us from detecting the mannose receptor (MR) on splenic macrophages and inflammatory dendritic cells (DC), or from confirming a role for MR in OVA uptake by the latter (1). We have analyzed MR expression on cells purified with or without collagenase digestion with identical results: macrophages express MR, but steady-state DC do not (Fig. 1). Furthermore, OVA uptake was not affected by the use of collagenase (Fig. 1). Some commercial preparations of collagenase contain trypsin-like activity that might affect MR detection or OVA uptake; we used collagenase tested for the absence of this activity. Previous studies also failed to detect MR in steady-state DC (3, 4). These studies included in situ staining of tissue sections, which would … 1To whom correspondence should be addressed. E-mail: villadangos{at}wehi.edu.au.

Exosomes: Naturally Occurring Minimal Antigen-Presenting Units

Abstract: Exosomes are secreted spherical structures that are limited by a lipid bilayer and contain cytosolic components from the producing cell. Exosomes form in intracellular multivesicular compartments of the endocytic pathway, and are secreted upon fusion of these compartments with the plasma membrane. Secretion of exosomes had been described initially in reticulocytes differentiating into red blood cells, and proposed to allow elimination of useless proteins. But exosomes became the object of increasing interest from immunologists in the late 90s, when antigen presenting cells where shown to secrete exosomes bearing functional Major Histocompatibility Complex molecules, able to induce activation of cognate T cells. Since then, a large amount of work has strengthen the idea that exosomes secreted by antigen presenting cells could represent « minimal antigen presenting units ». In this review, we describe the biophysical and biochemical specificities of exosomes, give an overview of their antigen presenting functions, and discuss their use for immunotherapies.