Changes

==MHC I==

==MHC I==

[[Image:MHC I.jpg|thumb|200px|right|'''MHC I presentation pathway, courtesy of B. Catchpole, 2008''']]

[[Image:MHC I processing.jpg|thumb|200px|right|'''MHC I presentation pathway, courtesy of B. Catchpole, 2008''']]

===Structure===

===Structure===

* MHC class I is expressed on virtually all nucleated cells

* MHC class I is expressed on virtually all nucleated cells

* Only MHC class I that is associated with peptide will be expressed at the surface

* Only MHC class I that is associated with peptide will be expressed at the surface

** The immune system is therefore able to see antigen from intracleeular pathogens

** The immune system is therefore able to see antigen from intracleeular pathogens

==MHC II==

==MHC II==