Voie d'immunisation et séquence d'administration de l ... - TEL

tel-00827710, version 1 - 29 May 2013
1) Presentation of intracellular antigen on MHC-I molecules
MHC-I molecules are expressed by all nucleated cells and allow for the presentation of
intracellularly synthetized peptides on their surface. Basically, endogenously synthetized
proteins are degraded by the proteasome or the immunoproteasome in the cytosol and
transferred into the endoplasmic reticulum (ER) through the TAP transporter (Buckwalter and
Albert, 2009). They are then loaded on MHC-I molecules, which transit through the Golgi
complex to reach the cell surface (Figure 2, pathway 1, red arrows).
Figure 2. Generation of MHC-I-peptide complexes from endogenous and exogenous antigen. The
pathway 1 (red arrows) corresponds to the direct presentation of endogenously synthetized peptides.
The pathway 2 (blue arrow) represents the cross-presentation of exogenous antigens. Figure from
Buckwalter et al., 2009.
2) Presentation of extracellular antigens
In order to be presented, extracellular antigens must first be taken up from the outside
environment by the APC. Different endocytosis pathways will be used for this process,
depending on the nature of antigen of interest. Particulate antigens, such as cell-associated
antigen, are taken up by phagocytosis whereas receptor-mediated endocytosis or pinocytosis
24