P1 Spring Cells Hypersensitivity Reactions

Front 1

List features of type 1 hypersensitivity reaction.

Back 1

•anaphylactic ("atopy") reactions
•IgE mediated
•allergen cross links IgE on mast cells and basophils which degranulate
•Th2 response instead of Th1 (Th2 cells activate B cells, which produce IgE instead of IgG)
•lots of eosinophils (and neutrophils)
•runs in families (chromosome 5)
•eg hay fever, asthma, hives, food allegies, eczema, allergic rhinitis

Front 2

List features of type 2 hypersensitivity reaction.

Back 2

•characterized by ADCC: "antibody dependent cell cytotoxicity"
•IgG or IgM (mediated), they attach to Ag on cells
•complement is activated
•target cells are destroyed
•eg blood transfusions, erythroblastosis fetalis, autoimmune hemolytic anemia

Front 3

List features of the type 3 hypersensitivity reaction.

Back 3

•immune complex mediated reaction
•Ag-Ab induces complement
•infiltration of neutrophils
•eg Arthus reaction, serum sickness, necrotizing vasculitis, glomerulonephritis, RA, systemic lupus ("SR SNAG" is not immune to anything, and snags all of these)

Front 4

List features of type 4 hypersensitivity reaction.

Back 4

•Cell mediated (delayed hypersensitivity)
•sensitized Th1, Th2, or CTLs release cytokines that activate macrophages or Tc cells, that damage cells
•eg contact dermatitis, tubercular lesions, graft rejection

Front 5

What (specifically) causes degranulation of mast cells and basophils, and what aids this?

Back 5

Ca+ causes degranulation.

ionophores increase membrane permeability to the extracellular Ca+.

Front 6

What are the cytokines released during type 1 HS (hypersensitivity)?

Back 6

IL-3
IL-4
IL-5
IL-13
TNF
GM-CSF
prostaglandin D2
leukotriene A4
(NOTE) Histamine is a neurotransmitter, not a cytokine

Front 7

What recepter is crosslinked in type 1 HS?

Back 7

FceRI

Front 8

List the type 1 HS pathways that occur after crosslinkage.

Back 8

•PLC cleaves PIP2 -> IP3 and DAG
•DAG activates PKC
•IP3 releases Ca+ from ER
•Adenylyl cyclase converts ATP to cAMP
•PLA2 (phospholipase A2) is activated, producing leukotrienes and prostaglandins

Front 9

What substances increase in the cytoplasm prior to the release of histamine during type 1 HS?

Back 9

cAMP and Ca+

Front 10

Classify the type 1 HS (hypersensitivity) inflammatory mediators.

Back 10

1.primary type 1 (histamine mainly)
2.secondary type 1 (leukotrienes, prostaglandins, cytokines)

Front 11

What do the primary type 1 mediators target?

Back 11

histamine receptors (H1 - H4)

Front 12

What does attachment to histamine receptor H1 cause?

Back 12

Anti parasite effects:

1. smooth muscle contraction (expel parasites)
2. inc mucous secretion by goblet cells

Front 13

What does attachment to histamine receptor H2 cause?

Back 13

1.inc vasopermeability (of caps?)
2.inc vasodilation (of caps?)
3.inc acid secretion by gastric cells (stomach)
4.suppresses degranulation (neg feed of mast and baso cells)

Front 14

List properties of leukotrienes and prostaglandins, and what they cause.

Back 14

•secondary type 1 HS inflammation mediators
•they're synthesized and released after primary type 1 mediators.
•more potent and longer lasting than primary type 1 med.
•their rate limiting enzyme is PLA2
•they cause bronchoconstriction, inc vascular perm, inc mucous secretion

Front 15

List properties of cytokines in reference to HS reactions.
List 3 examples.

Back 15

•secondary type 1 inflammation mediators
•enable local infiltration by eosinophils & neutrophils
•include IL-4 and IL-13 (stimulate Th2 response)
•include IL-5 (recruits/activates eosinophils)

Front 16

Cause and result of systemic anaphylaxis?

Treatment?

Back 16

CAUSE:
•allergens get into the blood
RESULT:
•systemic vasodilation → huge drop in BP
•bronchial smooth muscle contraction → difficulty breathing
TREATMENT:
•epinephrine (inc CO, relaxes SM)

Front 17

List cause and symptoms of asthma.

Back 17

CAUSE:
•mast cells degranulate in lower respiratory tract
SYMPTOMS:
•bronchoconstriction
•respiratory edema
•inflammation
•mucous secretion (fatal: mucous plugs)
PNEUM: asthma is "BRIMing" with symptoms

Front 18

What occurs during phase 1 of asthma, and what is responsible?

Back 18

•vasodilation, bronchconstriction, some mucous
•histamine, leukotrienes, prostaglandins are responsible

Front 19

What occurs during phase 2 of asthma, and what is responsible?

Back 19

•recruitment of eosinophils and neutrophils
•damage to ECs, more mucous
•cytokines are responsible