Which cells present endogenous antigens to CD8 T cells via MHC class I?

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Multiple Choice

Which cells present endogenous antigens to CD8 T cells via MHC class I?

Explanation:
Endogenous antigens are presented on MHC class I by any cell that has a nucleus, allowing CD8+ cytotoxic T cells to survey for viral or abnormal proteins inside the cell. The pathway starts when a cell degrades its own proteins in the cytosol with the proteasome, peptides are transported into the endoplasmic reticulum by TAP, then loaded onto MHC class I molecules and sent to the cell surface. Because MHC class I is expressed on all nucleated cells, nearly every cell can present endogenous peptides to CD8 T cells. Erythrocytes lack a nucleus and therefore do not express MHC class I, so they do not participate in this surveillance. Platelets are anucleate as well and are not the standard presenters in this pathway. The idea that only professional antigen-presenting cells present antigens on MHC class I is incorrect; professional APCs specialize in presenting via MHC class II to CD4 T cells, but for MHC class I, most nucleated cells can present endogenous peptides to CD8 T cells.

Endogenous antigens are presented on MHC class I by any cell that has a nucleus, allowing CD8+ cytotoxic T cells to survey for viral or abnormal proteins inside the cell. The pathway starts when a cell degrades its own proteins in the cytosol with the proteasome, peptides are transported into the endoplasmic reticulum by TAP, then loaded onto MHC class I molecules and sent to the cell surface. Because MHC class I is expressed on all nucleated cells, nearly every cell can present endogenous peptides to CD8 T cells.

Erythrocytes lack a nucleus and therefore do not express MHC class I, so they do not participate in this surveillance. Platelets are anucleate as well and are not the standard presenters in this pathway. The idea that only professional antigen-presenting cells present antigens on MHC class I is incorrect; professional APCs specialize in presenting via MHC class II to CD4 T cells, but for MHC class I, most nucleated cells can present endogenous peptides to CD8 T cells.

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