Autoimmunity Part 2 Flashcards
What are examples of Type I hypersensitivity reactions?
asthma, allergy, and anaphylaxis
What are examples of Type II hypersensitivity reactions?
Good pasture and Autoimmune Hemolytic Anemia
What are examples of Type III hypersensitivity reactions?
SLE, Serum sickness and Arthus Reaction
What are examples of Type IV hypersensitivity reactions?
Contact dermatitis, TB infections, Type I DM, RA
Describe the immediate and late phase of type I hypersensitivity reactions?
immediate- starts minutes later and can last hours. Causes vasodilation, increased vascular permeability and smooth muscle contraction (bronchioconstriction)
late- occurs 2-24 hours later and consists of a cellular inflammatory reaction that mediates tissue damage
What is the primary effector cell of type I hypersensivity reactions?
mast cells
a circulating mast cell is called a _______?
basophil
What are some examples of direct mast cell activators?
anaphylatoxins (C5a and C3a), IL-8, some drugs, bee venom
What are the two antibody classes that can activate complement?
IgG and IgM
What are the primary antibodies in the humoral response?
IgG
What are the mediator and effector cells of type II hypersensitivity reactions?
mediator: antibodies
effectors: complement proteins and phagocytic cells
What are the four general mechanisms of type II hypersensitivity reactions?
1) opsonization and phagocytosis
2) antibody-dependent cellular cytotoxicity
3) complement and Fc receptor mediated inflammation
4) Antibody-mediate cellular dysfunction
Describe ADCC
NK cells target and kill cells with low levels of IgG on their surfaces. Cells are killed or lysed, NOT phagocytosed and NK are the effector cells, NOT T cells. This process is often used for eradication of parasitic reactions and is seen in transfusion reactions and erythroblastosis fetalis
What is an example of complement and Fc receptor-mediated inflammation?
Good pasture
What is an example of antibody mediated cellular dysfunction?
Graves disease and myasthenia gravis; results in dysfunction of targets cells without inflammatory or direct cellular injury
Type IV hypersensitivity reactions are directed against _______.
intracellular pathogens
_______ result from chronic or persistent exposure to DTH-inducing antigen
granulomas
a mutation in the AIRE gene results in what disease?
autoimmune polyendocrinopathy
What are the 4 mechanisms of peripheral tolerance?
1) anergy
2) suppression of regulatory T cells
3) clonal deletion by activation-induced cell death
4) antigen sequestration
What cells express CD25?
regulatory T cells
What is the function of regualtory T cells?
act to locally inhibit autoreactive T cells by the secretion of IL-10 and TGF-B
What is IPEX?
an autoimmune disease resulting from mutations in Foxp3, a TF needed for activation of regulatory T cells. I- immune dysregulation, P- polyendocrinopathy, E-enteropathy, X-x-linked
an ANA test is _____ for lupus, but not _______
sensitive (everyone has it); specific (because other diseases have ANAs too)
antibodies to ____ and _____ are specific to lupus
dsDNA and Sm (smith) antigens
