Immuno Exam 2 - Lymphoid organs and lymphocyte trafficking (chapter 7 pg 1-23)

primary lymphoid organs

bone marrow and thymus

where do B cells and T cells originate?

bone marrow

where do T cells develop?

thymus

secondary lymphoid organs

lymph nodes, spleen, MALT (mucosal-associated lymphoid tissue)

where are lymphoid follicles found?

All secondary lymphoid organs

which lymphoid follicles are a loose network of follicular dendritic cells (FCD) rich in naive B cells or memory cells

primary

which lymphoid follicles which are found after antigen stimulation and contain a germinal center

secondary

follicular dendritic cells

follicular dendritic cells location

secondary lymphoid organs

what do follicular dendritic cells do?

catch and display Ag to B cells

FDCs have receptors that bind to what?

complement proteins and Fc region of Ab

once a B cell is activated, the number of B cells can double every how many hours?

6

proliferating B cells push aside other B cells to cause what?

dark zone

microstructures where proliferating B cells congregate and either become plasma cells, go through somatic hypermutation, or class switch

germinal centers

somatic hypermutation does what?

fine tunes Fab regions

where are new mutations tested?

light zone

where does class switching occur?

dark zone

All secondary lymphoid organs have

lymphoid follicles

what cell type migrates to B cell area to help activate B cells?

activated helper T cells

How can antigens enter the lymph nodes?

blood or lymph

lymphocytes leave blood and enter lymph node via what?

HEV (high endothelial venules)

structure of lymph nodes

cortex, paracortex, medullary sinus

what is found in the cortex of a lymph node?

B cell area containing lymphoid follicles

what is found in the paracortex of lymph node?

T cells

entry point for B and T cells to enter secondary lymphoid organs from blood

HEV

endothelial cells in blood vessels usually _________ and offer less room for passage of cells

overlap

HEV cells in blood are columnar which allows what?

more room for passage of cells