24 - immune system in action Flashcards
what are symptoms of infectious diseases causes by?
by direct effects of pathogens - infectious agents
or
indirectly by immune responses
direct mechanisms of tissue damage by pathogens
exotoxin production
endotoxins
direct cytopathic effects
indirect mechanisms of tissue damage by pathogens
immune complexes
anti-host antibody
cell-mediated immunity
what is leprosy caused by?
Mycobacterium leprae
intracelular bacteria
granulomatous lesions
nasal droplets spread
armadillos are a vector
granulomatous lesions in leprosy
macrophages come to get rid of it but instead form a large mass of cells
what are the 2 kinds of leprosy?
tuberculoid
lepromatous
tuberculoid leprosy
- infected usually live
- low infectivity
- granulomas and local inflammation
- nerve damage
- normal serum immunoglobulin levels
- normal T cell responses
lepromatous leprosy
- infected usually die
- high infectivity
- disseminated infection - bond, cartilage and bad nerve damage
- hypergammaglobulinemia
- low or absent T cell response
what is immunodeficiency?
affects ability to fight infection
primary or secondary
primary immunodeficiency
- due to intrinsic defects in immune system
- genetic
- most conditions are rare
- can be dominant or recessive, autosomal or X-linked
secondary immunodeficiency
immune system initially intact
consequences of another condition
causes: • malnutrition • lymphoproliferative disease • immunosuppressive drugs • infection • stress
what are the 4 types of hypersensitivity reactions?
I
II
III
IV
type I sensitivity
allergy
IgE binds to receptors on mast cells to activate them
what is anaphylaxis?
severe allergic reaction
IgE
• increase histamine
• increase TNF-alpha
• increase vasodilation
what do EpiPens do?
epinephrine
• increase vasoconstriction
• increase blood glucose
type II sensitivity reactions
antibody dependent
eg. erythroblastosis fetalis
• anti-Rh antibodies in pregnancy
type III sensitivity reactions
immune complex reactions
- autoantibodies to DNA and other Ags
- immune complexes form
- deposited at susceptible sites
symptoms include
• glomerulonephritis
• rash
• arthritis
eg. systemic lupus erythematosus (SLE)
type IV sensitivity reactions
cell-mediated
e.g. type I diabetes
• organ specific autoimmune response
• attack of beta cells
• over reactive effector T cells
what is immunotherapy?
activating the immune system to fight cancer
antibodies used to bind tumours or cytokines
