The nature of immunity Flashcards
What are the most important features of the immune system? (3 answers)
specificity, memory and self-discimination
What are the 2 main responses to a pathogen?
recognition (location of the pathogen + the type of pathogen) and defence
what are the physical barriers of the body? (2 answers)
skin and mucosal areas (e.g. sinuses, eyes, oral cavity)
2 steps of the innate immune response
recognition of the pathogen and the recruitment of effector mechanisms that kill and eliminate the pathogen
what are polymorphonuclear cells and which ones exist?
also callled granulocytes - because the cells contain granules. basophils (acidic granules - bind to basic stains e.g. haematoxylin), eosinophils (basic granules - bind to acidic stains e.g. eosin) and neutrophils (granules dont bind to neither of the stains)
what is the most abundant cell type in the body?
neutrophil
What is the main function of neutrophils?
the effector cells of innate iummune response - they are the first ones to be recruited to sites of infection + can work in anaerobic conditions ( often the case of damaged tissue)
What are the products of neutrophils?
azurophilic granules
which cell type contains azurophilic granules and what is inside the granules? (4 answers)
neutrophils. the granules contain enzymes - myeloperoxidase and lysozyme, bactericidal/permeability-increasing protein, cationic proteins - alpha defensins, cationic glycoproteins -serprocidins
what is the bactericidal / permeability-increasing protein and what isits function?
antibiotic protein with potent killing activity against gram-neg bacteria (it binds to LPS produced by bacteria
what is the function of cationic proteins i.e. alpha defensins?
killing activity against many gram-negative, gram-pos, fungi and enveloped viruses
what cytokines do neutrophils secrete?
IL-1, -6, -8, TNF-alpha, colony-stimulating factor (CSF), IFN-alpha
what is the main function of eosinophils?
defence against helminth worms and other intestinal parasites (when the pathogens are too large to be phagocytosed)
which products of eosinophils are pre-formed?
enzymes (eosinophil peroxidase - triggers histamine production, and eosinophil collagenase - remodelling of connective tissue) and toxic proteins (major basic protein - toxic to parasites and mammalian cells + triggers the release of histamine, eosinophilcationic protein - toxic to parasites, neurotoxin)
which products of eosinophils are newly synthesized?
cytokines
how do eosinophils recognize a parasite?
eosinophils express FcεRI - receptor which recognizes IgE opsonized parasites
what is the mechganism of action of eosinophils?
extracellular digestion