Abstract
Apicomplexa parasites such asToxoplasma gondiitarget effectors to and across the boundary of theirparasitophorous vacuole (PV), resulting in host cellsubversion and potential presentation by MHC classI molecules for CD8 T cell recognition. The host-para-site interface comprises the PV limiting membraneand a highly curved, membranous intravacuolarnetwork (IVN) of uncertain function. Here, using acell-free minimal system, we dissect how membranetubules are shaped by the parasite effectors GRA2and GRA6. We show that membrane associationregulates access of the GRA6 protective antigen tothe MHC I pathway in infected cells. Although inser-tion of GRA6 in the PV membrane is key for immuno-genicity, association of GRA6 with the IVN limitspresentation and curtails GRA6-specific CD8 re-sponses in mice. Thus, membrane deformations ofthe PV regulate access of antigens to the MHC classI pathway, and the IVN may play a role in immunemodulation.