ICS - Immunology Flashcards
Haematopoiesis starts with…?
Multi potential hematopoietic stem cell (hemocytoblast)
What do hemocytoblasts differentiate into?
- Common myeloid progenitor
- Common lymphoid progenitor
What do common myeloid progenitors differentiate into?
- Megakaryocytes (—> thrombocytes)
- Erythrocytes
- Mast cells
- Myeloblast (—> basophil, neutrophil, eosinophil, monocyte (—> macrophage))
What do common lymphoid progenitors differentiate into?
- Natural killer cell
- Small lymphocyte (—> T lymphocyte, B lymphocyte (—> plasma cell))
Describe innate immunity
- Rapid and non-specific defence system
- Present from birth
- Focused around physical and chemical barriers
- No lymphocyte involvement
Give examples of physical and chemical barriers used in innate immunity
Skin, mucociliary escalator, gastric acid, hairs, lysozymes
What do lysozymes do?
Destroys bacterial cell walls
When do monocytes become macrophages?
When they migrate from blood to tissue
Describe the role of neutrophils
Phagocytosis and bactericide
Describe the role of macrophages
Phagocytosis, antigen presenting and cytokine secretion
Describe the role of basophils
Secrete histamine and heparin in allergic reactions, eczema, hayfever etc.
Describe the role of eosinophils
Release cationic granules in parasitic infections
Describe the role of mast cells
Release histamines when IgE binds to them during anaphylaxis and asthma (type 1 hypersensitivity reactions)
Describe the role of natural killer cells
Release lytic granules that kill virus infected cells
Describe the role of dendritic cells
Antigen presenting cells that reside in the epithelium (liver = kupffer, skin = langerhans)
Describe the role of antigen presenting cells
Process and present antigens from pathogens for recognitions
What are the main antigen presenting cells (considered ‘professional’ at activating lymphocytes)?
Dendritic cells (also macrophages and B cells)
How are bacteria/fungi destroyed?
Phagocytosis
How are viruses destroyed?
Cellular shutdown/resistance and apoptosis
Which leukocytes are polymorphonuclear?
Neutrophils, basophils and eosinophils
Which leukocytes are mononuclear?
Monocytes, B lymphocytes and T lymphocytes
Where do T cells mature?
Thymus
Where do B cells mature?
Bone marrow
How do T cells recognise antigens?
T cells cannot recognise soluble antigens. Antigens must be displayed by an APC and bound to MHC1/2 in order to be recognised