lung infection and immunity Flashcards
host defence: summarise the host defenses against infection in the airways and recall how they may be compromised (congenital and acquired)
what initiates an immune response to inhaled bacteria
airway epithelial cells
how is the immune response initiated
signal leukocytes to move from bloodstream into the lungs and airway
what are used in innate immunity
alveolar macrophages, recruited phagocytes (e.g. neutrophils), local Ig (IgA - unspecific and found in secretions)
what are used in adaptive immunity
lymphocytes; T lymphocytes vs IC pathogens, B lymphocytes produce antibodies
how can host defences be compromised
excessive mucus production so cannot move bacteria
what are conchi and what is their role in lung infection
ridges of bone covered with respiratory epithelia; increase SA of nasal mucosa to condition air (warms/cools air, mositens air, captures particulates/bacteria)
mechanical defences against airway infection
upper respiratory tract filtration, mucociliary clearance, coughing, antimicrobial peptide secretion
local defences against airway infection
antiproteases, alveolar macrophages, IgA
systemic defences against airway infection
polymorphonuclear granulocytes, complement, circulating antibodies
decribe BALT (bronchus associated lymphoid tissue)
samples antigens inhaled through nose and produces antibodies against these
cause and outcome of acquired pathogenic damage to cilia
viral infections can lead to destruction of cilia and tight junctions between epithelial cells, before opportunistic bacteria invade; cilia must regrow, taking weeks, and can regrow as useless compound cilia
what can congenital microtubule abnormalities in cilia lead to
non-functional cilia and dextrocardia (heart towards right side) because these guide cells during embryogenesis (so if dextrocardia identified, check cilia function)
what does a lack of outer dyein arm in cilia in congenital dyein arm defects prevent
cilia from moving even if present, stopping mucociliary clearance and causing infection
what does a lack of nasal nitric oxide cause in congenital primary ciliar dyskinesia (autosomal recessive)
malfunctioning cilia
how do viral infections increase risk of bacterial infection
fewer cilia cells and increased watery secretions so harder to move
