L08 Flashcards
What are things that determine the type of effector mechanism needed for an immune response
Type of pathogen, localisation, challenge, stage of infection.
What are the locations of infections?
Extracellular or intracellular
What are the types of extracellular sites of infection?
Interstitial spaces, blood, lymph and epithelial surfaces
What are the types of intracellular sites of infection?
Cytoplasmic or vesicular
What are the components of protective immunity for interstitial spaces?
Ab, complement, phagocytosis and neutralisation
What are the components of protective immunity for epithelial spaces?
Ab (IgA) antimicrobial peptides
What are the components of protective immunity for cytoplasmic spaces?
cytotoxic t cells and NK cells
What are the components of protective immunity for vesicularspaces?
T cell and NK dependent Mq activation
What are the features of innate defence mechanism?
Rapid
Barriers, complement, phagocytes, NK cells, antimicrobial peptides.
First line of defense
Nin-specific
Ineffective against many pathogens
What are components of the anatomical barriers
Skin, oral mucosa, respiratory epithlilium, intestine
What are components of the anatomical barriers
C3, defensins, RegIIIgamma
What are components of the innate immune cells
Mq, granulocytes, natural killer cells
What are components of adaptive immunity
B cells/antibodies, T cells
What are the type of bacteria?
Gram +ve (Staphylococcus aurues, Streptococcus spp.) and Gram -ve (Campylobacter, Salmonella, Shigella, Haemophilus, Neisseria)
What makes gram -ve bacteria?
Thin peptidoglycan layer
What makes gram +ve bacteria?
thick peptidoglycan layer
Can components of the bacterial cell wall induce an innate response?
Yes
How can components of the bacterial cell wall induce innate responses
Bind to Toll-like receptors on MQ or NOD-like receptors in cytoplasm
How many TLR genes do humans have
10
What is a PAMP
pathogen-associated molecular patterns
what is a prr?
pathogen recognition receptor
What does the binding of PAMP and PRR result in?
Inflammation, dendritic cell maturation, influence differentiation of T cells, activates B cells (T1)
Why is phagocytosis effective against bacteria
bacteria can have protective capsules, Ab and complement can opsonise it
What does streptococcus pneumoniae cause?
Pnemonia, middle ear infection, meningitis
What Ab are produced by streptococcus pneumoniae?
Ab against capsular polysaccharides
What does the vaccine against streptococcus pneumoniae contain?
23 polysaccharide stereotypes
What type of vaccine is used against streptococcus pneumoniae?
Conjugate vaccine
What is the role of Ab in bacterial infection
Opsonisation, complement activation, bind to and neutralise toxins, bind to surface structures to prevent mucosal adherence.
What does complement activation look like in bacterial infections?Ys
Promote inflammation via C3a and C5a
Opsonise by binding C3b receptors on phagocytes
Lysis of Gram negative organisms (MAC C5b, C6, C7, C8, C9)
Can gram negative be killed by complement lysis?
Yes
What type of gram -ve bacteria is resistant to complement?
Neisseria spp.
Can some bacteria survive within phagocytosis?
Yes
How does mycobacterium tuberculosis evade phagocytosis
Inhibits phagosome fusion
Why is the Th1 response important
Cytokines activate Mq
Give examples of two cytokines that activate Mq
TNF alpha, IFN gamma
Why are activated Mq better than non-activated Mq in terms of responding to infection
Better at phagocytosis and killing
More efficient APC
Stimulate inflammation
What are the different types of cytokines are involved in granulomatous leprosy
TH1 cytokines (IL-2, IFN -gamme) and monokines (TNF-alpha, IL1beta, TGF beta)
What are the different types of cytokines are involved in lepromatous leprosy
TH2 cytokines (IL-4 IL-5, IL-10)
What type of pathogens are Ab useful against?
Extracellular
What type of pathogens are T cell effector mechanisms useful against?
Intracellular
Name an example of a pathogen that can result in the formation of granulomas
Mycobacterium leprae
What is LPS and on what type of bacteria?
Lipoplysaccharide & gram negative
What kind of infections can Neisseria spp cause?
Meningitis and gonnorhea
Name an infection which results in the production of a potent toxin
E.coli
Why can the same infectious agent cause different distinct pathologies?
challenge level, host immune system, age, co-
morbidities
