Lecture 14 Flashcards
What is the function of a secondary lymphoid organ?
organized aggregates of B cells and T cells where
immune response to pathogens are initiated
What are the secondary lymphoid organs?
spleen, peyers patches, isolated lymphoid follicle, lymph node
What is lymph composed of? What does a lymph capillary look like?
- blood plasma derivative
- blind-ended sac with valves
What is an HEV?
specialized post-capillary high endothelial venules located in the T cell zones of the lymph nodes and mucosal lymphoid tissues
- FUNCTION: allowing lymphocytes to enter the lymphoid organs
Why are HEV’s selective?
adhesion molecules and chemokines on the surface
What is contained by the primary and secondary (germinal centre) lymphoid follicles of the lymph node?
primary: non-activated B cells
secondary: proliferating Ag-activated B cells
(or a combination)
What is the function of the red pulp and white pulp?
red: removes old RBCs
white: arises when the lymphocytes surround the arterioles running through the spleen
What is the PALS?
periarteriolar lymphoid shealth (PALS) contains T cells
What does GALT consist of?
Peyer’s Patches, ILF, appendix and tonsils/adenoids of the throat
What is the structure of Peyer’s Patches?
subepithelial dome filled with T cells, B cells, DCs
- B cell follicles with small T cell areas surrounding the follicles
- anitgen enters via the M cell
What is the structure of an isolated lymphoid follicle?
- one small B cell follicle and an M cell-containing epithelium
What are CAMS?
cell adhesion molecule
- single transmembrane polypeptide
- roles in cell adhesion
- often ligands for integrins
What are selectins?
single transmembrane polypeptide
- binds carbohydrate
- initiate leukocyte-endothelial interaction
What are integrins?
heterodimers of alpha and beta subunits
- bind to CAMS,
- extracellular matrix activation leads to strong adhesion
What is ICAM-?
cellular adhesion molecules that have an extracellular domain folded like an immunoglobulin domain
