Cells & Tissues of the Immune System Flashcards
Types of T cells
Tgamma-delta, Talpha-beta
Lymphocytes
B lymphocytes
T lymphocytes
Types of Talpha-beta cells
CD4 => Th1, TH2, TH17, Tfh, Treg
CD8
T cell surface markers
CD4, CD8, CD3
B cell surface markers
CD79
B cell function
secrete Abs
B cell Ag Receptor
membrane form of Ig (IgM or BCR)
B cell location in secondary lymphoid tissues
follicles (nodules)
general helper T cell functions
help adaptive immune responses by activating other cells
Th1 function
activate macrophages
Th2 function
activate eosinophils
Th17 function
activate neutrophils
Tfh function
activate B cells
Treg function
inhibit adaptive immune responses & help avoid immune responses to “self” Ags
Tc function
kill cells that express Ags of intracellular pathogens
T cell Ag receptor
TCR
Location of T cells in secondary lymphoid tissues
diffuse tissue
Types of Primary Lymphoid Tissues
bone marrow, thymus, cloacal bursa, ileal Peyer’s patches
Primary Lymphoid Tissue def.
where lymphocytes mature from precursor cells
Where do all lymphocytes originate from precursors in?
bone marrow
T cells mature in
the thymus
B cells mature in the
cloacal bursa, ileal Peyer’s patches, bone marrow
Secondary Lymphoid Tissue def
where mature lymphocytes encounter Ag & are activated in adaptive immune responses.
Types of Secondary Lymphoid Tissues
spleen, lymph nodes, Mucosa-Associated Lymphoid Tissues (tonsils, intestinal Peyer’s patches, lymph nodes draining mucosal tissues)
Function of secondary lymphoid tissues
filter foreign antigens
spleen filters
blood-borne antigens
Mucosa-Associated Lymphoid Tissues (MALT) filter
Ags entering at mucosal surfaces
Lymph Nodes filter
Ags in any tissue that it drains
Mucosal Immune System lymphoid tissues are
different than other lymphoid tissues
Anatomic features of mucosal immune system
- intimately associated with epithelium
- specialized Ag uptake mechanisms (M cells)
Effector mechanisms of mucosal immune system
- Activated/memory T cells predominate
- Activated Treg cells present
- Secretory IgA
- Distinctive microbiota
Immune regulation of mucosal immune system
- active suppression predominates (food)
- inhibitory macrophages & DCs
Naive lymphocytes
lymphocytes that haven’t previously recognized Ags & been activated
naive lymphocytes circulation patterns
circulate between blood and secondary lymphoid tissues
How do lymphocytes enter the spleen from the bloodstream?
directly via the blood
How do lymphocytes enter lymph nodes & Peyer’s patches from the blood stream?
via venules with specialized endothelial cells in diffuse tissue
How do Ags & DC carrying Ags move from infected tissue to lymph nodes?
via lymphatic vessels
Mucosal lymphatic tissues get Ags and DC from..
mucosal surface and lamina propria
memory lymphocytes circulation pattern
tend to return to type of lymphoid tissue where they were first activated
with minimal cross-over
mucosal infection vaccines (resiratory, GI)
provide better local immunity if given at mucosal site but have shorter duration of immunity compared to systemically administered vaccines
Effector B cell circulation patterns
migrate from follicular tissues into medullary cords (lymph nodes), red pulp (spleen), lamina propria (mucosal-associated lymphoid tissue) or bone marrow.
where is most plasma cell IgG production done?
bone marrow
Effector T cell circulation patterns
migrate from lymphoid tissues into infected tissues, where they’re needed to do their effector functions
