Foundations of Immunology Flashcards
Lymphatic system consist of___
Cervical Axillary Bronchial Abdominal Inguinal
Lymphatic Ducts
Right lymphatic duct
Thoracic duct
Function of lymphatic system
Drainage of tissue (away)
Absorption and transport of fatty acids
Immunity
What are the walls of the lymphatic vessel composed of__
simple squamous epithelial cells
Lymphatic drainage
Lymph»_space; Afferent vessel»_space; LN»_space; Efferent vessel»_space; Lymphatic trunk»_space;> Lymphatic ducts»_space;> Venous system (subclavian or jugluar vein)»> Blood
Lymphoid organs
Primary: bone marrow
Secondary: spleen, thymus, lymph nodes, tonsil, cutaneous immune system, mucosal immune system (Peyer’s Patch)
Thymus T cell education
- Generated in the bone marrow
- Matures in thymus
- Positive selection: check for either CD4+ or CD8+
- Negative selection: check cells do not react to self
Low affinity interactions of T cells
Positive selection
Survival signal
High affinity interactions of T cells
Clonal deletion
MHC 1
CD8+
MHC 2
CD4+
The spleen consists of ____
White pulp and Red pulp
White pulp
Lymphocytes
T cell zone
B cell zone
Red pulp
Vascular sinusoid Large number of RBC Macrophages Dendritic cells Sparse lymphocytes Plasma cells
Function of spleen
Blood filter and immune function
Lymph Node Structure
T cell zones
B cell zones
HEVs
Function of lymph node
Filter and purify the lymph before it enters the venous system
Maintain and produce mature B cells and house T cells
HEV
High endothelial venules
Specialised post-capillary swelling that enables lymphocytes circulating in the blood to directly enter the lymph nodes
Peyer’s Patch
Aggregates of lymphoid cells that protrude inside the intestinal lumen
Function of Peyer’s patch
Initiate immune response in gut
M cells transport antigen to Peyer’s patch
This antigen is carried to the LN that drain it
Tonsils
Lymphoid tissues on either side of the throat
Involved in defence of upper respiratory infection
MHC class 1 is_____
found on virtually all nucleated cells
Trigger cytotoxic response
Prevents virally induced peptides to CD8+ T cells
MHC class 2 is_____
found only on professional APCs (macrophages, dendritic cells and B cells)
Presents antigen to CD4+ T cells
Effector T cells
Th1
Th2
Th17
Tfh
Th1
Cytokines, target cells, immune reaction, host defence, role in disease
IFN-y, macrophages, macrophage activation, intracellular pathogens., autoimmunity and chronic inflammation
Th2
Cytokines, target cells, immune reaction, host defence, role in disease
IL-4, IL-5, IL-13, Eosinophils, Eosinophil and mast cell activation, Helminths, Allergy
Th17
Cytokines, target cells, immune reaction, host defence, role in disease
IL-17, IL-22, Neutrophils, Neutrophil recruitment and activation, extracellular bacteria and fungi, autoimmunity, inflammation
Tfh
Cytokines, target cells, immune reaction, host defence, role in disease
IL-21, B cells, Antibody production, Extracellular pathogens, autoimmunity (autoantibodies)
How do cytotoxic T cells kill cells?
Release perforin
Forms pores in target cells
Also release granzyme B enter through pores form and induce apoptosis
B cells recognise____
T cells need to be shown____
Free organic antigen on BCR (IgM)
protein antigen in association with MHC
Plasma cells are responsible for____
antibody production
It is more important to tolerise____ than ____ because
T cells and B cells, B cells cannot make antibodies to most antigens without the help of T cells
Antibody classes
IgG, IgA, IgM, IgD, IgE
IgG
Four different forms
Good opsoniser
Only antibody that can cross the placenta to give passive immunity to foetus
Activate classical pathway
IgA
Protects mucosal surface, resistant to stomach acids
IgM
Expressed on B cells
Primary response to pathogens before IgG
Can activate classical complement system
IgD
Antigen receptor on B cells
Activate basophils and mast cells
IgE
Found in circulation
defends against parasites
triggers anaphylatic shock and allergies (mast cell, histamines)
Function of complement system
The complement system helps antibodies and phagocytic cells clear pathogens from an organism
