Barrier Function of Innate Immunity Flashcards
what are innate mechanisms hardwired for
neutralisation of many threats regardless of previous exposure
what are the four features of innate immunity
- barrier defence
- complement cascade
- inflammation
- innate immune cells and PRRs
what are complement proteins
cleavable proteins that are activated when proteins recognise microbial surfaces, bind antigen antibody complexes or experience low level spontaneous cleavage
activates a chain reaction
what are the effects of complement cascades
- phagocyte recruitment
- coating of pathogens to mark them for phagocytosis (opsonisation)
- form pores on the surfaces of microbes to kill them
what are the main barrier types in innate immunity
structural
chemical
biological
why are the tight junctions between epithelial cells protective
they prevent large particles and microbes from passing through to the other side as long as the epithelium is not compromised
what is the function of commensal bacteria in protecting the body
prevent pathogen colonisation
train the immune system
aid with digestion and vitamin production
what are some chemicals and proteins that can destroy pathogens
- antimicrobial enzymes like lysozyme
- antimicrobial peptides like histatins, cystatins and cathelicidins
what does lysozyme do
breaks down peptidoglycan in bacterial cell walls
what are defensins
small, with a positively charged region and a hydrophobic region which disrupts pathogen membranes
what are cathelicidins
inactive protein precursors that must be cleaved and then they function to disrupt membranes
what are histatins effective against
pathogenic fungi
what comprises the skin microbiome
gram positive bacteria, has multiple strategies to prevent infection like production of antibiotics and proteases
produce AMP from skin cells too
what are the skin cells that aid in protecting the body
keratinocytes
they are dead and resist viral infection as viruses need living cells to survive and spread
produce beta defensins
