Immunology Flashcards
What is a lysozyme
An anti microbial enzyme in some secretions, part of the innate immune system
Which stem cell progenitor is used for the innate immune system
Myeloid
Which stem cell progenitor is used for the adaptive immune system
Lymphoid
Neutrophil primary lysosomes
Combine with phagosomes to digest their contents, they contain myeloperoxidase, muramidase, acid hydrolases and defensins
Neutrophil secondary granules
Are secreted, they contain complement activators and enzymes eg lactoferrin and lysozyme
Which enzymes are needed for the respiratory bursts used for energy for phagocytosis in neutrophils
MPO and NADPH oxidase
What is used by macrophages for phagocytosis
Perioxidase lysosomes
What receptors do macrophages have
Fc, PRR toll-like and mannose receptors so can bind to all microbes
Macrophage in bone marrow/ blood
Monocyte
Macrophage in liver
Kupffer cell
Macrophage in lymph nodes
Sinus histiocytes
Macrophage in lungs
Alveolar macrophages
Macrophage in connective tissue
Tissue macrophages (histiocytes) leading to giant cells
Macrophage in skin and mucosa
Langerhans cells
Macrophage in CNS
Microglia
Macrophages in bone
Osteoclasts
Macrophages in granulomas
Epithelioid cells
Placenta macrophages
Hofbauer cells
Macrophages in kidney
Intraglomerular mesangial cells
Peyers patches macrophages
LysoMac 💪🏻
What type of leukocyte is a monocyte
Mononuclear
What type of leukocyte are basophils and eosinophils
Polymorphonuclear
Name a high affinity IgE receptor
FCER1 present on mast cells and basophils
What type of leukocyte and lymphocytes
Mononuclear
What is CD3
T cell receptor complex which activated t lymphocytes
What’s he difference between T helper 1 and T helper 2 cells
Th 1 helps immune response against intracellular pathogens. Th2 helps to produce antibodies against extra cellular pathogens
What surface markers are displayed by T regulatory cells
FoxP3 and CD4
Which surface marker is expressed by natural killer cells
CD56
What is complement
20 serum proteins, must be activated, involved in opsonisation and lysis of pathogens
Classical pathway of C3 convertase formation
Antibody-antigen complex, antibody binds antigen. This is adaptive
Alternative pathway of C3 convertase formation
Microorganism route, complement binds microbe
Lectin pathway of C3 convertase formation
Microorganism route, mannose binding lectin binds to microbe
What are C3a, C4a and C5a
Pro inflammatory mediators causing amplification, inflammation and cell recruitment
What does C5b activation lead to
Opsonisation and removal of immune complexes
What does C5b-9 activation do
Forms membrane attack complexes which insert into microorganisms causing cell lysis
Antibody definition
Protein produced in response to an antigen, it can only bind with the antigen which induced its formation (specificity)
Antigen
Molecule that reacts with preformed antibodies and specific receptors in T and B cells
Epitope
The part of the antigen that binds to the antibody/ receptor binding site
Affinity
Measure of the binding strength between an epitope and an antibody binding site
What does IgG1 do
Cleaves protein
What does IgG2 do
Cleaves carbohydrate
What does IgG3 do
Cleaves protein
What does IgG4 do
Associated with allergens. Only IgG not to activate complement.
3 main IgG functions
Activated complement, cleaves antigens and neutralises pathogens
What does IgM monomer do
Binds to B cell receptors
Describe IgM structure
Large pentamer held together by a J chain
What does IgD do
It is a transmembrane monomeric receptor on mature B lymphocytes
Cytokines
Proteins release by cells activated by antigens, invoked in cell to cell communications
Interleukins
Act between cells of the immune system
Chemokines
Induce chemotaxis of leukocytes
Interferons
Induce antiviral resistance in uninflected cells and therefore limit the spread of viral infection
Chemokine definition
Chemostatic cytokines which create a gradient to direct leukocytes and other cells from the blood to the site of infection
Extravasation
Leukocyte transendothelial migration
Inflammation definition
Series of reactions which bring cells and molecules of the immune system to sites or infection or damage
Acute inflammation
Complete elimination of a pathogen followed by resolution of damage, disappearance of leukocytes and full regeneration of tissue
Chronic inflammation
Persistent unresolved inflammation
What are the hallmarks of inflammation
Increased blood supply, increased vascular permeability and extravasation
What senses microbes in the blood
Monocytes and neutrophils
What senses microbes in the tissues
Macrophages and dendritic cells
Which PAMP do scavenger PRR bind to
Lipid on foreign bacteria
Which PAMP do toll like receptor (PRR) bind to
Foreign shapes e.g RNA
Which PAMP do lectin PRR bind to
Sugars on foreign bacteria
Why is opsonisation
Chemicals are modified to have stronger interactions with cell surface receptors, increasing attraction.
What’s the sequence of extravasation
TNf release causes adhesion molecules to be released so endothelium becomes sticky. Neutrophils adhere then move up chemokine gradient into the cell.
Name 3 acute phase proteins
C reactive protein, mannose binding lectin and surfactant protein A
Name primary lymphoid tissues
Bone marrow and thymus
Name secondary lymphoid tissues
Spleen, lymph nodes, mucosal associated lymphoid tissue (MALT)
What codes for major histocompatability complex
Human leukocyte antigen genes
What is neutropaenic sepsis
Where all neutrophils are removed, leading to sepsis. This can be a consequence of chemotherapy.
Which structural similarities can be identified by PRRs
Gram stain, double stranded RNA, CpG motifs
What are defensins
Eg Cathelicidin. They’re antimicrobial peptides secreted in lining fluids
What are lectins and collectins
Eg. MBL and surfactant protein A and D. Carbohydrates containing proteins which bind to carbohydrates or lipid in cell walls to activate complement and improve phagocytosis
What are petroxins
Eg. CRP they have antimicrobial actions
What does TLR 2 look for
Bacterial gram positive cell walls
What does TLR3 look for
Viruses
What does TLR3 look for
Bacterial endotoxin
What does TLR 7 look for
Viral RNA
What does TLR 8 look for
Viral RNA
What does TLR 9 look for
Bacterial DNA
What do mannose receptors on macrophages identify
Fungi
What do dectin-1 receptors on phagocytes identify
Beta glucans in fungal cell walls
What do scavenger receptors in macrophages identify
Lipid on foreign bacteria
What do nod like receptors identify
Peptidoglycans and break down products
What do RLRs identify
Double stranded Viral RNA and DNA
What did polly matzinger discover
Tissue damage products are hydrophobic and detected by TLRs
Extracellular damage molecules
Fribrinogen, hyaluronic acid, tenascin C
Intracellular damage products
MRNA, uric acud and heat shock proteins
Which two public health interventions have had the greatest impact
Vaccines and clean water
What is passive immunity
The transfer of preformed antibodies from one person to another
Natural passive immunity provides protection against
Diphtheria. Tetanus. Poliovirus. Mumps. Rubella
Artificial passive immunisation is used when
No time for immunisation, B cell defects, antivenoms and antitoxins, acute danger of infection and in vulnerable patients
What do passive immunity antitoxins act against
Botulism, tetanus, diphtheria
Which antivenins are given by passive immunity
Snake bites, insects, jelly fish
Passive immunisation is used prophylactically against which infections
Hepatitis, measles, rabies
What is somatic hypermutation
B cell receptors are diversified to recognise antigens and allows immune system to adapt its response to new threats
Active immunisation definition
Manipulating the immune system to generate a persistent protective response against pathogens by safely mimicking natural infection
Which diseases are treated with live attenuated pathogens
TB typhoid MMR
Which diseases are treated with whole inactivated pathogen
Cholera, pertussis, plague, Hep A, influenza
Subunit vaccines
Purified molecular components used as immunogenicity agents
How do aluminium salts act as adjuvants
Form precipitates and potentiate opsonised phagocytosis
How do chemicals act as adjuvants
Cause inflammation and irritation
How do toxoids and killed organisms act as adjuvants
They trigger the immune system and send out danger signals
What do NLRs do
The detect intercellular pathogens
Which antibodies are involved in allergy
IgE, IgG4 and IgA
Define allergy
abnormal response to harmless foreign material
Define atopy
A tendency to develop allergies
Define atopic individual
Someone who has an allergic response
Does IgE fix complement or lead to a proinflammatory repsonse
No
What is IgE half life
2.5 days
What is IgG half life
23 days
What is IgE serum concentration
0.3-100 microgram/ml
What is IgG serum concentration
1000 microgram/ml
Why is it hard to influence IgE binding pharmakinetically
As IgE binds to FCERI with a very high affinity
What is CD23
FCER11, receptor which regulates IgE. Is a leukaemia marker
What is a distinguishable feature of mast cells structure
ckit surface protein which is a receptor for stem cell factor. Needed for mast cell development in bone marrow
What causes mast cell granule release
IgE crosslinking
Which protein levels will be raised during anaphylaxis
Tryptase (protease from mast cells) and histamine
What is anaphylaxis
An immediate response to allergic stimuli, it occurs within minutes unless it is contained within GI
Which cytokines are involved in Th1
IL 2,10,12,18 and TNF-a
Which cytokines are involved in Th2
IL 3,4,5,6,10 and GM-CSF
What do the interleukins released from mast cells cause
Amplification
What does GM-CSF release from mast cells cause
Macrophage and eosinophil activation
What does Xolair/ omalizumab do
Blocks IgE binding via FCERI
Define hypersensitivity
Excessive or innapropriate reaction to an environmental agent, often immunologically mediated
Define autoimmunity
Abnormal state where the body’s immune system reacts against its own tissues or constituents
What is anergy
Absence of a normal immune response, can be because there arent two signals to activate CD4 T cells. Like in immunological tolerance to self antigens.
What is primary immunodeficiency
Caused by an inherent flaw in the immune system which increases the susceptibility of infections
What is secondary immunodeficiency
Caused by an environmental factor which compromises the immune system
What is a sentinal lymph node
The first lymph node draining a cancer, will be the hottest on PET scan
Which cancers commonly spread to bone
Breast, prostate, lung, thyroid and kidney
How big are slices of CT scan
1cm
Define adjuvant therapy
extra treatment given after surgical excision
What is the action of the vinblastine chemotherapy
Binds to mitotic spindles of dividing cells and stops them contracting, preventing replication - antimicrotubule agent
What is the action of etoposide chemotherapy
Binds to topoisomerase II and prevents DNA replication
What is the action of ifosamide chemotherapy
Cross links DNA and therefore inhibits DNA synthesis
What is the action of cisplatin chemotherapy
Cross links DNA and therefore inhibits DNA synthesis
What is myelosuppression
Where bone marrow activity is decreased
Name some fast dividing tumours
germ cell tumours of the testes, leukaemias, lymphomas, embryonal paediatric tumours, choriocarcinomas (placenta cancer)
How is her-2 identified
fluorescent in situ hybridisation and immunohistochemistry
What are the disadvantages of monoclonal antibodies
They are expensive and have to be given by IV infusion and dont cross BBB so dont treat brain mets
