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Role of viral protein splicing in immunity to infections with respiratory viruses

Tuesday 5 May 2009

Dr Alice Sijts

The group of Alice Sijts at the Division of Immunology of the Veterinary Faculty is interested in the basic mechanisms that lead to protective T-cell responses to infections, which is of importance for rational vaccine design. A second research interest, in collaboration with Dietmar Zaiss, concerns the role of mast cells in local immune regulation.

Project
CD8 T cells play an important role in protection against respiratory viruses such as Influenza, Respiratory Syncitial Virus (RSV) and its murine equivalent, Pneunomia Virus of Mice (PVM). CD8 T cells recognize short protein fragments (peptide epitopes) that are presented by MHC class I molecules and are generated upon intracellular degradation of viral proteins by a large protease complex, the proteasome. Recently, it was shown that proteasomes generate antigenic peptides not only through protein degradation, which leaves peptides with a length of 3-16 amino acids, but also by post translational protein splicing. Thus, in the latter case, two non-contiguous peptide products, generated by the proteasome, are ligated while still in the catalytic channel of the proteasome. (Nature. 2004;427:252-6; Science. 2004 304:587-90; Science. 2006;313:1444-7).

All epitopes described to be generated by protein splicing derive from self antigens (tumor associated antigens and a minor histocompatibility antigen). However, as the efficiency of epitope splicing increases with increasing antigen concentration, and as virus-infected cells produce large quantities of viral antigens, we assume that protein splicing plays an important role in the generation of MHC class I presented epitopes during viral infection as well. In several commonly used mouse infection models, vigorous CD8 T cell responses are detectable following viral infection. However, conventional methods of epitope identification have failed to reveal the viral sequences that are targeted by this T cell response. This project will test whether these epitopes are generated by protein splicing.

Techniques
Quantitative analysis of CD8 T cell responses in lungs and spleens of infected of mouse tisssues, Cell culture, Transfection of cells with plasmid/cDNA constructs, trunsduction of cells with retro-/lentiviral vectors,
Molecular biology: plasmid preps, bacterial transformation, DNA digestion, ligation, PCR

Duration
6 or 9 months

Contact
Dr Alice Sijts, E.J.A.M.Sijts@uu.nl, 030-2532471

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