Hyper 1 Flashcards
Type 1 H/S rxns are triggered by IgE-sensitized ___ cells
mast
main mediator in type I hyper rxn; occurs in response to an a____
IgE; allergen
which interleukin plays a vital role in the conversion to IgE in activated B cells?
IL-4; released by T cells. Induces isotype switch (tells B cells to switch) from IgM to IgE
two main proteoglycans found in mast cells:
heparin (anti-coagulant) and histamine
stimulation of mast cells: explodes to release h___, but also liberates ___ acid, which results in which two pathways?
histamine, arachidonic acid release: produces cyclooxygenase pathway and lipoxygenase pathway
3 main fxns of histamine (and other general stuff released by MCs) [VBC]
vasoDILATION, bronchoCONSTRICTION, chemotactic agent
-overall goal of histamine: mediates ITCHING
what does each pathway produce?? ***
cyclooxygenase: prostaglandins
lipoxygenase: leukotrienes
name the eosinophil chemotactic factor that is produced in the lipoxygenase pathway. What does it release/do?
LTB4; releases histaminase to limit H/S rxn (B/d histamine)
name the two types of mast cells: which produces histamine? Which is more active in producing prostaglandins (rather than leukotrienes)?
CT MCs, Mucosal MCs
CT (connective tissue) MCs DO produce histamine and more PG than leukotrienes
SAID drugs inhibit production of ____, while NSAIDs inhibit production of ____
SAID: no arachidonic acid (so no COX1 or 2; no prostaglandin pdtn)
NSAIDs: no COX1 specifically; no constitutive pathway (no promotion of platelet activity)
two main mechanisms of mast cell stabilizers:
- prevent IgE crosslinking (block Ca flux)
- inhibit IgE isotype switching
T/F: mucosal mast cells are involved in asthma d/t their histamine release
FALSE; mucosal mast cells (as opposed to CT MCs) DO NOT RELEASE HISTAMINE). they ARE involved, however, d/t their release of leukotrienes and tryptases
