Introduction to immunology Flashcards
In what two can the immune system cause disease?
Autoimmune and allergy
All cells of the immune response are ____ and are derived from _____ stem cells.
Haemopoietic and pluripotent.
What cell linages give rise to the immune cells?
Myloid and lymphoid.
What specificity does the innate immune system have?
Limited with broad categories.
What specificity does the adaptive immune system have?
Highly specific at the species and strain level.
How long does it take to activate the innate immune response?
Hours.
How long does it take to activate the innate immune response?
Days and in rare cases weeks.
The adaptive immune system is always active. T or F?
False, sometimes it will not be needed.
What organisms have an adaptive immune response?
Sharks and up.
Name five key components of the innate immune system?
- Phagocytes
- NK Cells
- Lysosomes
- Complement
- Interferons
What could the innate immune system possibly have?
A memory function
What barriers make up the innate immune system?
Chemical and physical
What type of features does the innate immune system recognise?
Invariable
What timescale do changes to the innate immune system happen on?
An evolutionary timescale.
How do changes happen to the innate immune system?
When remaining population members have developed some sort of resistance eg to HIV1 and Malaria (RBC gene functions)
When is the innate immune system crucial?
Between the period in which a child has lost the mothers AB in their serum but have not had the chance to develop their own.
Name the two crucial components of the adaptive immune system.
B and T lymphocyes
Antibodies
What can the memory function sometimes be?
Lifelong.
What is the normal delay of the adaptive immune response?
4-6 days
What sort of features does the adaptive immune system recognise?
Variable features.
What sort of pathogens does B cell immunity recognise?
Extracelluar pathogens
What sort of pathogens does T cell immunity recognise?
- Intracelluar pathogens
- Cell associated pathogens
- Small parasites
What are 3 key roles of B cell immunity?
- Activate complement
- Opsonise bacteria
- Coat to prevent binding
What sort of antigens does B cell immunity recognise?
Soluble free native antigens
Does the surface of the virus/ bacteria need to be altered to be recognised by cells involved in B cell immunity?
No
What does T cell immunity rely on to recognise pathogens?
MHC to display associated material.
What do the MHC peptides normally display?
Peptides and not carbs.
What is the humoral immunity?
The process in which plasma cells make antibodies.
B immunity
What are the main constituants of cell mediated immunity?
T helper cells producing cytokines.
T cytotoxic cells killing host infected cells in a specific manner
(T immunity)
What sort of cell is long lived and involved in scar formation?
Phagocyte
What cells are professional phagocytes?
Monocytes
Macrophages
Neutrophils
What professional phagocytes are found in the blood?
Monocytes
Neutrophils
What professional phagocytes are found in the tissues?
Neutrophils
Macrophages
What sort of nucleus do professional phagocytes have?
Mononuclear
What sort of nucleus do non professional phagocytes have?
Polymorphic granules
What non professional phagocytes are found in the blood?
Basophils
Eosinophils
What non professional phagocytes are found in the tissue?
Mast cells
What cells are non professional phagocytes?
Dendritic cells
Eosinophils
Basophils
Mast cells
What sort of infection do phagocytes respond to?
Bacterial
What cell of the immune system has a multilobed nucleus that can be stained by giasma stain?
Neutrophil
What are the 5 main roles of a neutrophil?
- Phagocytosis
- ROI production
- Microbe entrapment
- Cytokine production
- Antimicrobial release
Neutrophils can leave the blood upon infection. How do they do this?
- They can undergo successive tightening to capillary epithelial cells
- Escape the blood
- Migrate to specific locations via chemoattractants immobilised on glycoproteins
Where are neutrophils found in very large numbers?
Bone marrow
What phagocyte makes up 50-60% of blood phagocytes?
Neutrophils
Neutrophils are short lived if they do not encounter an infection. How short is short?
24 hrs.
What immune system cell is fast moving and can be quickly released when needed?
Neutrophil- quickly released as large numbers in the bone marrow.
What sort of phagocyte is known as a frustrated phagocyte?
Eosinophil
When are eosinophils activated?
In the late immune response
What are the main two roles of the eosinophil?
Allergy
Parasitic infections
What cells are similar to tissue mast cells?
Basophils
What phagocyte strictly does not circulate the blood?
Mast cells
What can mast cells release?
Inflammatory mediators
What cells are important in parasite infection/ allergy?
Mast cells
Basophils
Eosinophils
Where are mast cells mainly found?
Mucosal surfaces
What do mast cells have a high affinity to?
IgE Fc receptors
What sort of phagocyte is essential for human function?
Mast cell
Are mast cells heterogeneous or homogenous throughout the body?
Heterogenous
Name 3 places where mast cells can be found.
Skin, CNS, heart, Blood vessels, gut.
What phagocyte is the main type of APC?
Dendritic cells
Where can you find dendritic cells?
Skin and lymphoid tissues.
What do dendritic cells express and why?
MHC2 allowing presentation to the T cells.
What receptor do T helper cells express?
CD4+
What receptor do T cytotoxic cells express?
CD8+
What do CD4+ cells do?
- Stimulate the B cells to help produce antibodies.
- Activate macrophages
- Activate NK cells
- Assist with the development of CD8+ cells.
What do T cytotoxic cells do?
Recognise and kill infected host cells.
What do NK cells act against?
Infected host cells- intracellular bacteria or viral.
How do NK cells kill?
NK cells kill non specifically via the recognition of altered expression in host cells, ie they recognise the non self cell.
Why can NK cells have a potential anticancer role?
Because they kill non specifically through the recognition of altered self.
If an organism frequently mutates causing a change in surface proteins what can it be classified as?
Antigentically unstable
What is an example of an antigentically unstable organism?
HIV 1
Against what organisms is the innate immune system of a particular importance?
Antigentically unstable
We have learnt 6 examples of external threats. Name them
- Bacteria
- Viruses
- Protazoa
- Prions
- Fungi
- Parasites
Prions can be an external and an internal threat. When are they an internal threat?
When misfolded proteins are replicated.
Ischaemia is an internal threat. What is it?
Restriction in the blood supply to tissues.
The presence of a new and abnormal tissue growth can act as an internal threat. What is the proper name for this sort of growth?
Neoplasia
What is the main form of internal threat?
Blunt trauma
Prions, neoplasia and blunt trauma are all internal threats the body can face. Name an additional 3.
- Cancer
- Toxic Insult
- Necrosis
Necrosis is a form of an internal threat. What actually is it?
The premature death of cells caused by cell injury. Cells die by autolysis causing unregulated digestion of cell components.
What three things can cause necrosis?
- Infections
- Toxins
- Trauma
Commensal organisms are not harmful to us as they will not cause disease. True or false.
False. Some can under certain conditions.
Define Anaphylaxis.
Widespread activation of mast cells which can lead to death.
What phagocyte is known as a ‘big eater’
Macrophage
Are professional or non professional phagocytes involved in the formation of scars?
Non professional
What can ‘Big Eater’ phagocytes be described as?
Sentinel cells
Where are macrophages dervived from?
Myloid cells and circulating monocytes.
What macrophage is found in the lung?
Alveolar
What macrophage is found in the liver?
Kupfer
What macrophage is found in the CNS?
Microglia
Why do macrophages vary between tissues?
As they have undergone distinct differentiation depending on where they are found.
Macrophages have very high phagocytotitc ability. How many bacteria cells can they consume per cell?
100’s
What three types of receptors can drive macrophages?
- Scavanger
- Mannose
- Complement
What inflammatory mediator is involved in fever and sepsis?
IL6
What can macrophages produce in large volumes?
Inflammatory mediators
What inflammatory mediators can macrophages produce?
- TNF
- IL12
- IL beta
- IL6
What are the main roles of macrophages?
- Present to CD4+ cells to stimulate T cell activation.
- Produce interferon y
- Induce AB dependant cell cytoxicity
- Induce antigen specific phagocytosis
What three things can drive M1 and M2 macrophages?
- Chemokines
- Cytokines
- PAMPS
What sort of macrophage development is classed as ‘classical’?
M1
What sort of macrophage development is classed as ‘alternative’?
M2
What macrophage type is critical in inflammatory bowel disease?
M1
What diseases are M1 macrophages elevated in?
- Obesity
2. T1D
What is the main role of M1 macrophages?
Induce inflammation (pro inflammatory)
What is the main role of M2 macrophages?
Remodelling of tissue (tissue remodelling)
What class of macrophage can promote tumour growth?
M2
What class of macrophage can cause tumour resistance?
M1
What sort of macrophage is important in the development of scars?
M2
Large amounts of what macrophage type can cause tissue destruction due to the promotion of the TH1 response?
M1
What type of macrophage is responsible for angiogenesis?
M2
What type of macrophage is responsible for tissue destruction?
M1
What type of macrophage is responsible for immunoregulation?
M2
What type of macrophage kills intracellular parasites?
M1
What type of macrophage is involved in tissue encapsulation, including Mtb?
M2
What is expressed on all nucleated cells?
MHC1
What does the MHC1 class present?
Peptides derived form endogenous proteins.
What leuckocytes express MH2?
- Dendritic cells
- Macrophages
- B cells
What does the MHC2 class present?
Peptides derived from exogenous proteins.
What type of macrophage develops later and why?
MH2- develops due to a change in chemokine and cytokine production.
MHC2 expression is normally restricted. When is it not?
During Inflammation.
What are the HLA genes?
Genes which encode for the MHC. HLA stands for the Human Leucocyte Antigen.
Mice have 2 HLA genes How many HLA genes do humans have?
6
HLA genes are the most polymorphic genes humans have. Which HLA gene is most polymorphic in humans and how many alleles does it have?
HLA-B, which has >1400 alleles.
When you match for a graft injection what are you actually matching for?
MHC proteins.
How many base substitutions can be present between different MHC alleles?
20
What do MHC proteins play a major role in?
Initiating a T cell response by presenting antigen to T cells.
What is MHC variation NOT?
Somatic- inherited variation.
What does MHC restriction result in?
T lymphocytes only recognising antigen when in complex with a SELF MHC molecule.
How was the phenomena of MHC restriction discovered****?
- Inbred mice with different MHC proteins were immunised by a virus. The MHC proteins were the only differences between the mice
- The cytotoxic T cells were removed from these mice.
- The ability of removed cytotoxic T cells to kill infected was measured.
- Found that only T cells from A could kill infected T cells.
Why is the skin being dry a good mechanical defence?
Limited nutrients to bacteria.
The skin includes insoluble proteins to act as a barrier. Name an example of one of these?
Keratin
What provides defence molecules to act as a barrier?
Sweat
Epithelia in which body parts acts as a mechanical barrier?
GI tract, airways and uriogenital tract.
What prevents bacteria adhering?
Tears and Mucus
What organisms do not mount a strong immune response?
Commensal organisms
The fluctuating pH in the body provides an unfavourable environment for the body. Where does it fluctuate?
Low in the GI and high in the upper GI.
What are defensins?
Small toxic peptides that are poorly understood.
What microbicides are secreted constitutively?
- Lysozymes
- Histines
- Defensins
What cells secrete microbicides?
Cells exposed to the environment.
What can be embedded into tissues to add an extra line of defence?
Embedded cells
What are all cells capable of?
Some level of innate immunity
Why are macrophages found in the lungs?
Due to dirty air.
