Lecture 18-Hypersensitivity Flashcards
______ are immune responses that cause tissue injury
hypersensitivity reactions
what is type 1 hypersensitivity mediated and resulting from
mediated by IgE; results from actions of mediators secreted by the mast cells
what is type 2 hypersensitivity mediated and what does it cause
mediated by Abs that bind tissue Ags and cause complement-dependent tissue injury and disease
what is type 3 hypersensitivity mediated by and what does it cause
mediated by Abs that bind to circulating Abs to form immune complexes, which deposit in vessels and cause complement-dependent injury in the vessels wall (vasculitis)
what is type 4 hypersensitivity mediated by and what does it result from
mediated by T cells diseases and results from inflammation caused by cytokines produced by CD4+ Th1 and Th17 cells, or killing of host cells by CD8+ CTLs
what is type 1 hypersensitivity most triggered by
environmental antigens
define atopy
genetic tendency to develop allergic diseases
describe the immediate phase of a type 1 reaction
vascular and smooth muscle reaction to allergen develops within minutes after challenge
what is the late phase reaction of type 1 characterized by
inflammatory infiltrate rich in eosinophils, neutrophils, and T cells
what does histamine do in type 1 responses
major amine that causes the dilation of small blood vessels and increases vascular permeability
what do proteases do in type 1 reactions
cause damage to local tissues
who do prostaglandins do in type 1 reactions
vascular dilation
what do leukotrienes do in type 1 reactions
stimulate prolonged smooth muscle contraction
hyperthyroidism and graves disease is associated with what type of hypersensitivity
type 2
what type of hypersensitivity is myasthenia gravis associated with
type 2
what is different between type 2 and 3 hypersensitivity
the Ag in 3 is in circulation (soluble) while type 2 is typically tissue Ag
what is the major mechanism triggering damage in type 3 hypersensitivity
classical activation of complement and recruitment of leukocytes
what type of sensitivity is SLE associated with
type 2
what are the major triggers of type 4 hypersensitivity
autoimmunity, exaggerated or persistent responses to environmental Ags, and some microbial Ags
what autoimmune diseases are mediated by type 4 hypersensitivity
MS, rheumatoid arthritis, and type 1 diabetes
what Th cells are involved the most in type 4 hypersensitivity
Th1 and Th17 (the cytokines that they produce)
what interleukins are particularly involved in production of Ag-specific T cells in type 4
IL-12 and IL-2
what do inhibitors of calcineurin, Jaks and other kinases cause
inhibition of signaling
what do anti-IL-2r do
block T cell proliferation
what do Anti-IL-17 do
block inflammation
what do anti-p40 do
block Th1 and Th17 responses
what do anti-integrins do
block adhesion
what do anti-TNF, Anti-IL-1, and Anti-IL-6R do
block inflammation
what do CTLA4-Ig do
block costimulation
what are the principal clinical manifestations of SLE
rashes, arthritis, and glomerulonephritis
what are the most frequent auto-Abs found in SLE
anti-DNA Abs
what is the principal diagnostic test for SLE
presence of anti-nuclear Abs
what type of reactions is rheumatoid arthritis mediated by
type 2/3 hypersensitivity reactions
