Immunology! Flashcards
What is danger in terms of immunology?
Anything that could cause damage to the organism
What part of the physical defences would a wound or insect bite target?
The external epithelia
Where in the body are the mucosal surfaces found?
The airway, the gastrointestinal tract and the reproductive tracts
What do cells have embedded in their membranes that recognise types of pathogens?
Pattern recognition receptors - extremely diverse
What is a function of the lymph nodes?
A point in a network at which pathways intersect.
Describe red blood cells: How many are in the blood roughly? How many are made roughly per second? How long do they live for? What do they transport?
Roughly 5-6 x10^6 red blood cells in the blood, with 2x106 being made per second. They live for 110 days and transport CO2 and O2
What is a complement in terms of the immune response?
A cascade of proteins activated by antibodies which amplifies the inflammatory response. This has the ability to directly kill pathogens or attract immune cells.
Describe Neutrophils: Relative abundance, effect on pathogens, how they are recruited and lifespan.
They are the most abundant type of white blood cell. They are active phagocytic cells which can consume and kill pathogens. They are recruited by inflammation and live for a short time.
describe Macrophages: Where do they develop, effect on pathogens, activated by, and lifespan.
They develop in tissues from precursors. They are active phagocytic cells which can consume and kill pathogens. They are recruited by inflammation and are long lived.
Describe dendritic cells: Where do they develop, effect on pathogens, migration patterns, part played in the lymphatic system.
They develop in tissues from precursors. They are active phagocytic cells. They migrate out of peripheral tissues and carry proteins to the lymph nodes. This activates the adaptive immune response
What is the antigen/epitope?
The broken-down part of peptide chains - helps with specificity of the pathogen
What is a special function of B and T cells? What is the specific name for these?
They can specifically recognise antigens via specialised surface receptors. They are called B and T cell receptors.
How do T cells collectively recognise different forms of antigens?
They recognise processed antigen presented on MHC molecules on the surface of antigen presenting cells
What do CD4 T cells respond to?
Longer peptides in MHC class 2 molecules
What do CD8 T cells recognise?
short peptides in MHC class 1 molecules
Where are adaptive immune cells generated?
Thymus and Bone marrow
Where are the adaptive immune cells activated from?
Lymph nodes and spleen
What are the three stages of the adaptive immune response?
T cell activation –> T cell differentiation –> T cell effector stage
True or false: There is an information transfer from the pathogens to the adaptive immune cells to the innate cells?
False - the information is transferred to the adaptive cells by the innate cells, not the other way around.
Describe IgM in terms of avidity and affinity
Low affinity and a high avidity
Define avidity
The cumulative binding strength of an antibody
Describe IgG in terms of abundance
IgG is the most abundant type of B cell in the serum
What is IgE involved in?
The allergy and anti worm responses
Where is IgA found?
They are found at mucosal sites
How can antibodies protect the host?
Neutralise the pathogen, activate the complement to enhance the immune system, enhance phagocytosis by binding to receptors on phagocytes.
What types of cells express MHCII molecules?
Professional antigen presenting cells i.e. B cells.
What cells express MHCI molecules?
All nucleated cells
What does it mean if a cell is said to be cytotoxic?
It kills the cells at the site of infection, normally by triggering apoptosis
What does immunological memory enable?
The rapid control of pathogens met previously
What is variolation?
The deliberate exposure to controlled amount of infectious agent to induce infection and subsequent immunity
The eradication of which disease is described as “the single greatest health intervention in history”?
Smallpox
In relation to vaccines, what is attenuation?
The methods to prepare weakened versions of infectious agents as vaccines
What are some problems when developing vaccines against intracellular pathogens?
- You need to grow large amounts of the pathogen 2. You must figure out how to attenuate the pathogen 3. Figure out how to test the vaccine’s efficacy
How can you create a “killed” vaccine?
Use chemicals to heat or kill the organism. The antigens from the dead organism can still induce immunity
How can you create a “subunit” vaccine?
Isolate antigens from the virus and then the antibodies to those antigens can protect against infection
Name one example of a memory cell vs a naive lymphocyte
Memory = B cells Naive = CD4 & CD8 T cells
What are two defining features of CD4 & CD8 T cells in terms of immune response?
They have lower activation thresholds and better effector functions
What are three defining features of B cells in terms of immune response?
They produce more Ab, produce higher affinity Ab, and work better with IgG and IgA molecules in terms of effector functions.
