Immunology - Innate Immunity Flashcards
What is the precursor to cells in the blood?
Haematocytoblast
What 2 things do haematocytoblasts become?
Common myeloid progenitor
Common lymphoid progenitor
What do the myeloid progenitors become?
Megakaryocyte, erythrocyte, mast cell, myeloblast
What do myeloblasts become?
Eosinophils, basophils, neutrophils,
monocytes—> macrophages
What do lymphoid progenitors become?
Natural killer cell (NKC)
Lymphocyte (T cell, B cell —> plasma cell)
What cells are in which types of immunity?
Innate immunity- neutrophils and macrophages
Adaptive immunity- NKC, T and B cell, plasma cell
What are primary lymphoid organs?
Bone marrow & thymus
What happens in the bone marrow and thymus?
Bone marrow - all cells originate, B cells mature here
Thymus - T cell maturation + ‘thymic tolerance’
Where are secondary lymphoid organs?
Lymph notes
Spleen
What happens in the lymph nodes and spleen?
Lymph nodes - antigen presenting cell (APC) + T/B cell interactions
Spleen - RBC recycling, encapsulated bacterial killing
What are tertiary lymph organs?
Are they normal?
Pathological
Germinal centers of rapidly proliferating lymphocytes
Describe innate immunity
Specific?
Fast or slow?
Memory?
What cells are involved?
Non specific, rapid, already active (little activation needed), no memory
Killing usually via complement activation
Neutrophils and macrophages mainly
What are some physical and chemical barriers in the body?
Physical- skin, mucus, cilia
Chemical- lysozyme in tears, stomach acid
What does the complement system do?
Destroy foreign antigens by:
Direct lysis - membrane attack comp,ex formation (MAC)
Opsonisation - increased phagocytosis (C3b)
Inflammation - macrophage chemotaxis (C3a + C5a)
Neutrophils
% of WBC?
Act in how long?
What do they express?
Key mediator in?
Function?
70% of all WBC
Act in hours - days
Express CD66 receptor (common for all granulocytes)
Key in acute inflammation
Function: Essentially mini bombs of N.E, myeloperoxidases (MPo) & other ROS
Phagocytosis
Macrophages
Act in?
Where are they found?
Function?
What do they have?
Act in months - years
Can be circulating or resident (eg. Kupffer)
Clear apoptosis debris
Have toll like receptors, complement receptors & antibodies band & Fc component
Where are monocytes and macrophages found?
What 3 features do monocytes, macrophages and dendritic cells have?
Monocytes- only in blood
They migrate to tissue
Macrophages - stay in tissue not blood
Phagocytic, present antigens, release cytokines -attract other immune cells
Eosinophils
What do they contain?
When are they often seen?
What colour do they stain with what stain?
Contain major basic protein (MBP)
Often seen in parasitic infection
Stain pink with eosin
Where are mast cells and basophils found?
What are their function?
Mast cells = fixed at tissues
Basophils = circulating in body
IgE binding = degranulation = histamine release
T1 sensitivity
NK cells
What are they a key role in?
Function?
Key role in viral cell killing, self cell killing + malignant cell killing
Activation = degranulation—> perforin (perforated viral infected cells)
Receptors on these cells are?
Toll like receptors + nodlike receptors
TLRs detect different things such as:
2, 3, 4, 5, 7, 8, 9
2 - detects gram + & TB
3 - intracellular
4 - LPS (-) (lipopolysaccharide on gram - bacteria)
5 - flagellin
7 - single strand RNA
8- intracellular
9 - non methylated DNA
Which TLRs are intracellular?
Where are the rest?
3, 7, 8, 9
Rest are on CSN (extracellular)
What are non cell band receptors, free In blood called?
Lectins
What do lectins respond to?
PAMPs
DAMPs
Pathogen/damage associated molecular patterns
What are antigen presenting cells?
Which are the best type of APC?
What do they do?
Interface between innate and adaptive immunity
Dendritic cells
Present foreign antigens to T helper cells to either stimulate further Th proliferation or stimulate B cell production to antibodies
When dendritic + T cells communicate, they form?
Immune synapses
What 3 conditions must be met to function?
Receptor binding
Co stimulation (other molecules bind after 1^ receptor binding)
Cytokines release
…..otherwise no response (anergy)
