Intravacuolar Membranes Regulate CD8 T Cell Recognition of Membrane-Bound Toxoplasma gondii Protective Antigen

Cell Rep. 2015 Nov 23. pii: S2211-1247(15)01288-7. doi: 10.1016/j.celrep.2015.11.001. [Epub ahead of print]

 

Lopez J¹, Bittame A², Massera C², Vasseur V¹, Effantin G³, Valat A², Buaillon C¹, Allart S¹, Fox BA⁴, Rommereim LM⁴, Bzik DJ⁴, Schoehn G³, Weissenhorn W³, Dubremetz JF⁵, Gagnon J², Mercier C², Cesbron-Delauw MF², Blanchard N⁶.

 

Apicomplexa parasites such as Toxoplasma gondii target effectors to and across the boundary of their parasitophorous vacuole (PV), resulting in host cell subversion and potential presentation by MHC class I molecules for CD8 T cell recognition. The host-parasite interface comprises the PV limiting membrane and a highly curved, membranous intravacuolar network (IVN) of uncertain function. Here, using a cell-free minimal system, we dissect how membrane tubules are shaped by the parasite effectors GRA2 and GRA6. We show that membrane association regulates access of the GRA6 protective antigen to the MHC I pathway in infected cells. Although insertion of GRA6 in the PV membrane is key for immunogenicity, association of GRA6 with the IVN limits presentation and curtails GRA6-specific CD8 responses in mice. Thus, membrane deformations of the PV regulate access of antigens to the MHC class I pathway, and the IVN may play a role in immune modulation.
Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

PMID:

26628378

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