Processing of exogenous hepatitis B surface antigen particles for Ld-restricted epitope presentation depends on exogenous β2- microglobulin |
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Authors: | Reinhold Schirmbeck Stefan Thoma Jrg Reimann |
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Institution: | Reinhold Schirmbeck,Stefan Thoma,Jörg Reimann |
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Abstract: | Processing of exogenous hepatitis B surface antigen (HBsAg) particles in an endolysosomal compartment generates peptides that bind to the major histocompatibility complex (MHC) class I molecule Ld and are presented to CD8+ cytotoxic T lymphocytes. Surface-associated ‘empty’ MHC class I molecules associated neither with peptide, nor with β2-microglobulin (β2m) are involved in this alternative processing pathway of exogenous antigen for MHC class I-restricted peptide presentation. Here, we demonstrate that internalization of exogenous β2m is required for endolysosomal generation of presentation-competent, trimeric Ld molecules in cells pulsed with exogenous HBsAg. These data point to a role of endocytosed exogenous β2m in the endolysosomal assembly of MHC class I molecules that present peptides from endosomally processed, exogenous antigen. |
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Keywords: | β 2-microglobulin Major histocompatibility complex class I processing Hepatitis B surface antigen Cytotoxic T lymphocyte |
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