Immunology; Vaccinations Flashcards
What is an Antigen?
Component of foreign material that the body uses to recognise the foreign body
What is an Immunogen?
Body induces an immune response
Epitope/Antigenic Determinant
Within a given antigen, there are specific parts of the molecule that immune system uses to recognise it
Difference between Innate + Adaptive
Innate - non-specific, not affected by previous contact with infectious agent
Adaptive - highly specific recognition of an antigen + generation of immunological memory
What does immune cells arise from?
Single pluripotent progenitor cell within bone marrow
Whee does T-lymphocytes differentiate?
Thymus gland
What produces + secretes antibody?
B - lymphocytes
What are monocytes and macrophages?
Mononuclear phagocytic cells
What do mononuclear phagocytic cells secrete?
Secrete molecules that:
- Destroy bacteria directly
- Recruit other immune cells to site of infection
- Stimulate inflammatory response through Vasodilation
- Activate other immune cells to help destroy foreign body
Examples of granulocytes
Neutrophils, Eosinophils, Basophils
Function of neutrophils
Phagocytose microorganism to destroy them
Function of Eosinophils + Basophils
Involved in extracellular killing of microorganism
5 distinctive attributes of Adaptive immunity
(1) Specificity - act specific to invading molecule
(2) Inducibility - cells of AIS activated only in antigen response
(3) Clonality - once activated, cells proliferate + form identical cell (clones)
(4) Unresponsive to self - not act on the body’s own cells
(5) Memory - memory about specific pathogens
What could adaptive immune responses be?
Cell-mediated - body induces CMIR only against specific endogenous antigens which involves T cells
Humoral - body induces humeral response against exogenous pathogens + involves antibody production, involves B cells independently / dependent with T-helper cells
What does an antibody monomer consist of?
- 2 heavy polypeptide chains
- 2 light polypeptide chains
What regions are there in the FAB domain?
Variable region
Constant region
Function of Variable region
Involved in antigen recognition
Different sequence recognises different antigens
What state is antibodies produced?
B-lymphocytes in Naive state
Where are IgM + function?
Cell surface of B-lymphocytes in naive state
Act as surveillance molecules ready to bind to any invading antigen
Types of antibody
Ig GAME
Ig G
Secondary response of circulatory system
Ig A
Involved in Mucosal immunity
Ig M
Primary response of circulatory system
Ig E
Produced by mast cells + involved in the inflammatory response
Vaccination
Exposing individual to a specific antigen in an controlled, non-infectious manner to prime the body into making memory cells
What happens when body is exposed to antigen of infectious agent
Body will mount the immune response preventing the infection from taking hold
Vaccination programme
Protect people + communities against the most infectious disease
Meningitis
Infection of the meninges causing inflammation
Meninges
Protective membrane covering the brain + spinal cord
What causes meningitis
Viruses or bacteria
How many people contract bacterial meningitis + develop septicaemia in the UK each year?
Around 3,400 people
How many people will die of bacterial meningitis?
1 in 10
How many survivors will suffer side effects
1 in 4
Live vaccines
Live, infective microorganisms used to promote a similar response in the body as to a live infection.
Promotes life-long immunity but can cause issues such as making the person ill+ replication of microorganism
Killed + component vaccines
Contains dead components of microorganism (e.g. cell wall extracts)
Immune response towards antigenic components of microorganism
No life-long immunity + so repeated vaccinations need to be administered
DNA vaccines
gene encoding pathogenic antigen is introduced into human cells and transcribed to express antigenic protein: an immune response is launched by the body.
DNA is lost from the cell.
Example of live vaccine
Oral polio vaccine + MMR
Example of killed + component vaccine
DPT (diptheria, pertussis (whooping cough) + tetanus)
Example of DNA vaccine
Bird flu
How many types of bacteria cause meningitis + septicaemia
50
Common forms of bacteria to cause meningitis + septicaemia in the UK
Meningcoccal sp.
Pneumococcal sp.
What causes Meningcoccal infection
Neisseria meningitidis
Neisseria meningitidis
Gram-negative diplococcus bacterium that forms part of natural flora at the back of the nose + mouth
How can Neisseria meningitidis spread?
Passed from person to person in nasal or oral droplets (kissing or sneezing)
Main causative form of meningitis in the UK
Meningitis B
Who developed the Meningcoccal B vaccine
Bexsero, Novartis + received its marketing license from the European commission in January 2013
Why wasn’t Meningcoccal B vaccine introduced into the UK at first>
Joint committee on vaccination and Immunisation (JCVI) advise government not to introduce vaccine due to lack of evidence of cost versus benefit
When did Meningcoccal B vaccine get introduced
2014
How was Bexsero developed
Reverse Vaccinology
Method of Reverse Vaccinology
Genome sequence decoded
The proteins most likely to be ‘broadly-effective’ vaccine candidates are identified
% of strains of Meningitis B can Bexsero protect
73%
Types of vaccines
Live
DNA
Killed/component
