Hypersensitivities IV Flashcards
Type IV is antibody mediated. True or false?
FALSE
What is the timing of clinical signs with type IV?
2-3 days if prior sensitized
What cells are involved in type IV?
Th1, CTLs, macrophages
What Ig classes are involved in type IV?
none
Clinical syndrome type IV?
granulomas or cellular apoptosis induced by CD8s
Type IV reactions are ____-mediated tissue injuries.
cell
What is the immune mechanism for type IV reactions?
antigen sensitized Th1 CD4 T-cells and CD8 T-cells accumulate and release Th1 cytokines (IFN-y, TNF-a)
activated macrophages and cytotoxic T cells
When does a type IV reaction occur (time)?
at 72 hours- swelling, induration, or granuloma at site of antigen due to accumulation of macrophages and lymphocytes
What are the effector mechanisms of type IV?
cytokine mediated inflammation –> tissue injury
T cell mediated killing of host cells–> cell death and tissue injury
What is the bystander effect?
when molecules are being secreted to get rid of a pathogen end up damaging host cells/ tissue
What does a positive TB skin test mean?
Th1 immune response to myobacterium tuberculosis antigens
What antigens act as haptens and bind skin cells?
penicillin, poison ivy, metal ions
TB skin reaction is a ________ response to ______________.
memory Th1 ; myobacterium tuberculosis
What is the procedure for TB skin test?
purified protein derivative of M. tuberculosis (PPD) is injected into skin, it is processed by APCs and attracts memory affector T cells (mostly CD4) and macrophages
How long does it take to get a positive TB skin test?
48-72 hours
What is a negative TB test?
no swelling or induration
What is induration?
redness, firm swelling
What does a positive TB test mean?
the animal was previously exposed
Poison ivy oil acts as a ______ and binds to _______.
hapten; skin proteins
How does poison ivy cause a rash?
stimulates CTL’s to induce apoptosis of keratinocytes
What is the result of a topical reaction to penicillin?
contact dermatitis
What chemicals can cause contact dermatitis?
formaldehyde
nickel
How does formaldehyde cause contact dermatitis?
binds proteins easily causing skin hypersensitivity and asthma
How does nickel cause contact dermatitis?
nickel hapten binds to keratinocytes causing cytotoxic T cells to induce apoptosis of keratinocytes
What is the difference between in vivo and in vitro tests?
In vivo for cell-mediated immunity; invitro for T helper proliferation or cytotoxic T cell activity to antigen
How do you treat type IV?
avoid contact with chemical or substance
anti-inflammatory drugs
glucocorticoids
antibiotics if secondary infection
Organ skin grafts- antigen expressed by __ chromosome.
Y
Female tissue may be rejected by males. True or false?
False- male tissue may be rejected by females
Organ graft rejection is mainly due to ____ disparity.
MHC class 1
______ in immunosuppressed recipient destroys recipient’s cells and tissues.
foreign lymphocytes
When would a sperm granuloma develop?
develops in testicular tissue when spermatozoa leaks out following trauma
What is happening with the immune response to develop a sperm granuloma?
Th1 immune response with CTLs and activated macrophages
Sperm granulomas can lead to development of anti-___ antibodies.
sperm
