User:Eric Martz/MHC Answers: Difference between revisions
Eric Martz (talk | contribs) No edit summary |
Eric Martz (talk | contribs) No edit summary |
||
| Line 9: | Line 9: | ||
</li><br><li> | </li><br><li> | ||
<!--2-->All nucleated cells express MHC class I, although the levels of expression vary from tissue to tissue (and a few cell types express undetectable levels). Red blood cells, which lack nuclei, do not express MHC class I. A virus can target any cell type. In order for T cells to detect virus infection, all cell types must express MHC class I. | <!--2-->All nucleated cells express MHC class I, although the levels of expression vary from tissue to tissue (and a few cell types express undetectable levels). Red blood cells, which lack nuclei, do not express MHC class I. A virus can target any cell type. In order for cytotoxic T cells to detect virus infection, all cell types must express MHC class I. | ||
</li><br><li> | </li><br><li> | ||
<!--3--> | <!--3-->Only "professional" antigen-presenting cells (APC), such as dendritic cells and macrophages, constitutively express class II MHC. B lymphocytes also express MHC class II, which enables them to receive help from T helper cells. Professional APC phagocytose or endocytose whatever they encounter. B lymphocytes endocytose the specific antigen bound by their antibody receptors, presenting the resulting peptides on their MHC class II to Th cells. | ||
</li><br><li> | </li><br><li> | ||