1 Immunity Flashcards
immune system protects against
bacteria
viruses
fungi
parasites
bacteria examples
mycobacterium tuberculosis = tuberculosis
virus examples
influenza = flu
parasite examples
plasmodium falciparum = malaria
fungi examples
candida albicans = thrush
immune system challenges
diverse nature of pathogens
vast range of pathogens
rapid growth of microbes
minimise host damage
recognition
locate and identify pathogen
defence
repel or destroy pathogen
fundamental features of immunology
specificity
memory
self-discrimination
specificity
specific immune response
memory
from vaccination, subsequent infection rapid immunological response
self-discrimination
make sure will not recognise self
mucosal surface route of infection for pathogens
airway
GI tract
reproductive tract
airways infection
inhaled droplet - influenza virus causes influenza
spores e.g.Bacillus anthracis causes inhalation anthrax
GI tract infection
contaminated food/water e.g. rotavirus causes diarrhoea
reproductive tract infection
physical contact - HIV causes AIDs
external epithelia routes of infection for pathogens
external surface
wounds
insect bites
external surface infection
physical contact - Trichophyton causes athletes foot
wounds infection
puncture wounds - Clostridium tetani causes Tetanus
insect bites infection
mosquito bites - Flavivirus causes yellow fever
levels of defence against pathogens
mucosal surfaces
innate immunity
adaptive immunity
mucosal surface defence
have things in them that help repel pathogen
innate immunity defence
just behind the mucosal surfaces waiting to be activated if foreign objects enter
adaptive immunity defence
specialised recognises particular pathogen that enters the body
cells in innate immunity
macrophages mast cells natural killer neutrophil complement proteins granulocytes
macrophages
phagocytic cell
complement proteins
activated when pathogen comes into body
Neutrophil
phagocytic cells in the blood, they migrate from blood into tissues where pathogen is
Innate immunity features
- Quickly activated
- same on repeated exposure to the same microbe
- Moderate efficiency
- General response
innate immunity recognition
- Recognition of ‘pathogen-associated molecular patterns’ (PAMPs), e.g. bacterial lipopolysaccharide, viral double-stranded RNA
Cells of innate immune system express PRR on surface when a pathogen is present
Pathogens show PAMPS on their surface which is recognized
TLR recognise different PAMPS on bacterial surfaces
Some TLR are inside the cell many in cell recognize virus
adaptive immunity cells
B cell (antibodies-immunoglobins) T cells (help other cells of immune system / kill other cells of immune system – cytotoxic) Lymphocytes
adaptive immunity features
- slowly activated
- Improves on repeated exposure to same microbe
- High efficiency
- Specific response tailored to individual microbes
- Recognition of antigens specific to each type of microbe
what does adaptive immunity lead to
- Cell Mediated Immunity = T and B cells
- Humoral Immunity = antibodies
recognition of innate immunity
rapid response (hours)
fixed
limited number of specificities
constant during response
recognition of adaptive immunity
slow response (days to weeks) variable numerous highly selective specificities improve during response
what are innate immune cells recognised by
- Recognition by ‘pattern recognition receptors’ (PRRs) that are widely expressed on many cell types, e.g. toll-like receptors
what are adaptive immune cells recognised by
- Recognition by antigen-specific receptors clonally expressed by lymphocytes
what is the response to diverse pathogen nature
range of defence mechanisms
what is the response to vast pathogen range
vast antigen receptor range
what is the response to rapid microbial growth
rapid inflammatory response
what is the response to minimise host damage
regulatory mechanisms
