Innate Immunity 1 Flashcards
what is innate immunity?
non-specific, no lasting memory, first line of defence against the oral microbiota
what are the stages of innate immunity immediately after infection?
recognition by performed, non-specific and broadly specific effectors - removal of infectious agent
what are the stages of early induced innate response after infection?
recruitment of effector cells - recognition of PAMPs, activation of effector cells and inflammation - removal of infectious agent
what are the 5 groups of disease causing agents?
bacteria, viruses, fungi, protozoa, helminths
what do disease symptoms depend on?
where the pathogen replicates and the damage it causes
when is the innate immune response effective?
with regular contact with potential pathogens which are destroyed within minutes or hours, only rarely causing disease
what cells contribute to innate immune response?
epithelial/endothelial cells + fibroblasts
how does epithelium contribute to innate immunity?
it is a physical barrier and produces antimicrobial peptides, cytokines and chemokines
what are the innate cell subsets and complement?
phagocytic cells (macrophages and neutrophils) and antigen-presenting cells (dendritic cells)
what is the function of chemokines?
cell recruitment
what is the function of cytokines?
cell activation/proliferation
what are the different main components of innate immunity?
epithelium, innate cell subsets and complement, chemokines/cytokines
what is produced by the epithelium in the oral cavity?
antimicrobial peptides, immunoglobulins (secretory IgA), lactoferrin, lysozyme and cystatins
what do antimicrobial peptides do?
attach and disrupt membranes
when are antimicrobial peptides effective?
in low concentrations
what are the major families of the antimicrobial peptides?
beta-defensins, human neutrophil peptides, cathelicidins, psoriasin proteins
what are the two different functions of antimicrobial peptides?
directly kill microbes and modulate host immunity
how do antimicrobial peptides directly kill microbes?
there is an electrostatic interaction between the two cells, the AMP ruptures the membrane OR inhibits intracellular function both causing bacterial lysis
what are the different ways in which AMPs modulate host immunity?
recruit or activate immunocytes, neutralise bacterial products to suppress inflammation, enhance nucleic acid recognition to promote auto-inflammation
where is secretory IgA produced?
at mucosal surfaces
what does secretory IgA do when binded to a flagella?
prevents motility
what does secretory IgA do when it is binded to a bacterial toxin?
it neutralises it
how does secretory IgA prevent effects of microbes on mucosa?
it cross links target macromolecules and bacteria and prevents attachment of bacteria to mucosal surfaces
what is lactoferrin and what does it do?
glycoprotein that transports iron ions but has antimicrobial activity
where is lactoferrin present and what is it produced by?
present in saliva and produced by neutrophils
where are lysozymes present and what are they produced by?
present in saliva and produced by macrophages/neutrophils
what do lysozymes target?
cell walls of bacteria