769348
Descrição
FlashCards por sophietevans, atualizado more than 1 year ago
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Criado por sophietevans
mais de 10 anos atrás
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| Questão | Responda |
| True or false: dendritic cells were the first cells of the immune system to be discovered. | True! They were discovered by Paul Langerhans in 1868. |
| Why are dendritic cells named thus? | They are covered with long membranous extensions that resemble the dendrites of nerve cells. |
| What are the four major recognised categories of dendritic cells? | • Langerhans dendritic cells (lymph node) located in the skin • Interstitial dendritic cells (lymph node, spleen) in the interstitial spaces of all organs except the brain • Monocyte-derived dendritic cells located in lymphoid tissue Plasmacytoid-derived dendritic cells play roles in innate immune defence and as antigen presenting cells NB: (origin) |
| Although the four main categories of dendritic cell differ in their phenotype and functions, what cell surface molecules do they have in common? | They all share display of class I and II MHC molecules, and the B7 family of co-stimulatory molecules, CD80 and CD86, are present. They also possess CD40, a molecular that can influence T cell behaviour by interaction with a complementary ligand on T cells. |
| Outside of the lymph nodes, what do immature dendritic cells do? What would cause them to migrate to the lymph nodes? | Outside lymph nodes, immature forms of these cells monitor the body for signs of invasion by pathogens and capture intruding or foreign antigens. They migrate to the lymph nodes, where they present the antigen to T cells. |
| When acting as sentinels in the periphery, immature dendritic cells take on their cargo of antigen in which three ways? | • They engulf it by phagocytosis • They internalise it by receptor-mediated endocytosis • They imbibe it by pinocytosis (immature dendritic cells pinocytose fluid volumes of 1000 to 1500μm3 per hour, a volume similar to the cell itself) |
| Unlike other types of dendritic cell, which type does not arise in the bone marrow and has completely different functions? | Follicular dendritic cells. |
| Follicular dendritic cells do not express class II MHC molecules and therefore do not... | ...function as antigen-presenting cells for T helper-cell activation. |
| Where are follicular dendritic cells found? | They are exclusively located in the organised structures of the lymph node - the follicles, which are rich in B cells. |
| Follicular dendritic cells do not express MHC class II molecules, but do express high levels of... | ...membrane receptors for antibody, which allows efficient binding of antigen-antibody complexes. |
| Here is a picture of a follicular dendritic cell. | |
| Based on the presence of a surface molecular rather than tissue location or function, what are the two broadest classes of dendritic cell? | CD8α+ and CD8α-. |
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