Week 9 - Immunity Flashcards
What are the primary lymphoid organs?
Bone marrow
Thymus
What are the anti-microbial secreted immunity mediators?
Antibodies
Defensins
Interferons
Lytic enzymes
Cytotoxins
What are the regulatory / inflammatory secreted immunity mediators?
Cytokines
Chemokines
Prostaglandins
Histamine
What are the properties of innate immunity?
Quick activation
Same upon repeated exposure to same microbe
Moderate efficiency
General response to microbes
Recognition of PAMPs (pathogen-associated molecular patterns)
Recognition by PRRs (pattern recognition receptors)
What are the properties of acquired immunity?
Slower activation
Improvement on repeated exposure to same microbe
High efficiency
Specific response to individual microbes
Recognition of antigens specific to each microbe type
Recognition by antigen-specific receptors clonally expressed by lymphocytes
What is the primary immune response?
Epithelial barrier
Immediate local response / innate response (complement proteins and macrophages)
Early induced response / innate / inflammatory response (inflammatory mediators from complement, macrophages, mast cells –> attract leucocytes and serum proteins)
Later adaptive response (antigens carried to lymphoid tissue by dendritic cells –> T / B lymphocyte activation and Ab production –> recirculation to infection site)
What is immunopathology?
Diseases involving defects in the immune system (immunodeficiency, allergy, autoimmunity, transplant rejection, lymphoproliferative diseases)
What are the properties of B lymphocyte antigen recognition?
Antigen recognition receptors = membrane bound immunoglobulins
Surface immunoglobulins = surface receptors
Secreted immunoglobulins = antibodies
All receptors are identical on 1 cell
Interaction of antigen and receptor = B cell activation / proliferation
Further differentiation to form plasma cells
What happens during clonal selection?
Clone with most specific surface immunoglobulins = have primary response then secondary response to the infection –> less specific don’t undergo response to infection
What are the properties of blood?
A tissue
8% body mass
45% RBCs
1% WBCs and platelets
55% is plasma –> albumins = transport, colloidal osmotic pressure – globulins = transport, clotting, precursors to hormones, defence – fibrinogen = clotting
Serum = coagulated plasma
What are the properties of blood cells?
Discoid
No nucleus
Has haemoglobin for O2 / CO2 transport
120 day lifespan
Foetus and neonatal production = liver and spleen
Neonatal, child and adult production = bone marrow
What are the 5 leucocyte types and their proeprties?
Neutrophils = microorganism phagocytosis
Eosinophils = parasite killing and inflammation
Basophils = histamine release in hypersensitivity reactions
Monocytes = phagocytic, leave blood and become macrophages
Lymphocytes = produce antibodies
What are the types of phagocytes and immunocytes?
Granulocytes
Monocytes
Lymphocytes
How is white blood cell production controlled?
Colony-stimulating factors
CSFs stimulated by infection
Recombinant CSFs = improve reduced WBC count after anticancer drugs
Interleukins
What are the different blood groups and their properties?
Determined by RBC antigens
ABO and Rhesus = clinically important ones
A = A antigens, b-antibodies
B = B antigens, a-antibodies
AB = AB antigens
O = no A or B antigens, has a and b antibodies
O Rh -ve = universal emergency donor
What are the properties of blood counts?
Cells per volume –> machine or manually calculated
Haematocrit / packed cell volume –> centrifuge blood and find RBC % (male = 40-52%, females = 36-48%)
Haemoglobin –> amount per 1 Litre (males = 135-175 g/L, females = 115-155 g/L)
Identify anaemias
Mean corpuscular volume –> volume of individual RBCs –> identifies microcytic, macrocytic anaemia and alcohol abuse
What is Hb/RBC and Hb/PCV?
Hb/RBC = mean corpuscular Hb – reduced with iron deficiency or small cell size
Hb/PCV = mean corpuscular Hb conc. – reduced when large cells with impaired haem production
What are Rhesus D antigens required for?
+ve or -ve
Required in pregnancy –> new-born haemolytic disease
Prevent with Anti-D immunisation – Anti-D immunoglobulin
Give to mother after 1st child delivery
What are the components of blood and their functions?
RBCs:
Oxygen transport
WBCs:
Immune defence
Platelets:
Clotting
Plasma
What are not detected in blood?
Plasma calles
Macrophages
Mast cells
What are the properties of mast cells?
Recruit circulating leukocytes. Widening of vessels –> slower flow, induce arrestins –> inflammation, swelling
In most slides, mast cells have lost their granules due to the preparation Toluidine stained resin sections
What are the properties of macrophages?
Engulf foreign substances and cells and digest their contents.
Large cells, nucleus generally light, oval or even dented, often with nucleolus
What are the properties of plasma cells?
“antibody factories” differentiated from B-lymphocytes
Characteristic round nucleus with heterochromatin clumps around the periphery and in the middle. The nucleus is often off centre.
What are the properties of leukocytes?
Attracted to infected site from bloodstream –> swelling = caused by loosening of epithelial junctions for cell transit
What are secreted immune mediators?
Granulocytes, macrophages, natural killer cells, mast cells
Limited specificity
+ destructive power
Where are B and T lymphocytes generated?
In bone marrow
What happens during clonal selection of T cells?
Epitope binds to T cell receptor
T cell multiplies rapidly
Identical progeny formed
What happens during B cell differentiation?
Antigen binds with epitope to B cell receptor
Clonal amplification
Differentiate into plasma cells
Shed receptors, forming antibodies
What happens at the secondary lymphoid system?
Matching venues (lymph follicles, tonsils, lymph nodes, spleen):
where antigens and lymphocytes are matched