immunodeficiency Flashcards
what is immunodeficiency
dysfunction/deficiency of one or more components of adaptive or innate immune system
what is immunosuppression
inhibition of one or more components of adaptive or innate immune system
match the condition with the most probable cause:
a. immunodeficiency
b. immunosuppression
1. iatrogenic
2. acquired or genetic
immunodeficiencies are usually acquired or genetic, which immunosuppression is often iatrogenic
what are primary immunodeficiencies
inherited genetic abnormalities that cause the deficiency of one or more components of the immune system.
examples of primary immunodeficiency
chediak-higashi syndrome
SCID
canine x-linked severe combined immunodeficiency
equine agammaglobulinemia
selective immunoglobulin A deficiencies in dogs
what causes SCID in arabian foals
mutation in DNA-dependent phosphokinase results in non-functional VDJ assembly and recombination, and TCRs are not assembled. Therefore, no functional T cells emigrate from the thymus. THIS IS A PRIMARY IMMUNODEFICIENCY
what is the pathogenesis of canine x-linked severe combined immunodeficiency
a mutation in the gene that codes for IL-2 and IL-4 receptors results in impaired lymphocyte proliferation, leading to atrophied lymph nodes and thymus
what is equine agammaglobulinemia
horses have a defective BTK enzyme, which is required for light-chain gene rearrangement in B cells to occur. As a result, the horse gets no antibodies (rip)
what is selective immunoglobulin A deficiency in dogs
an IgA deficiency common in shar peis.
what are the six different secondary (acquired) immunodeficiencies/immunosypressions?
- virus induced
- malnutrition induced
- exercise/stress induced
- drug/toxin induced
- microbial/parasitic induced
6 age induced
what is an example of a viral induced immunosuppression
FIV
what are the five stages of FIV
- acute infection
- asymptomatic carrier
- persistent generalized lymphadenopathy
- AIDs-related complex (ARC)
- acqquired immunodeficiency syndrome (AIDS)
after the development of ARC or AIDS, cats survive how long
less than one year
what main thing is lost as viral load of FIV/HIV goes up
CD4
malnutrition induced immunosuppression
starvation results in suppression of T cell, macrophages, and NK functions. lots of nutritional deficiencies (zn, vit D, vit E) can affect the immune system
exercise induced immunosuppression
overtraining/ stress leads to increased cortisol, can impact antibody levels
drug induced immunosuppression
corticosteroids and cytotoxic/chemotherapeutic drugs cause immunosuppresion
what are the four types of drug therapies for cancer
chemotherapies
hormonal therapies
targeted therapies
immunotherapies
immunotherapeutic agents aim to stimulate ____
leukocytes
how do chemotherapeutic and immunotherapeutic drugs work synergistically
chemo kills rapidly dividing cells, which releases tumor antigens. immuno stimulates leukocytes to find these released tumor antigens and prime an anti-tumor immune response
what are monoclonal antibodies used for in vetmed
B-cell lymphoma, T-cell lymphoma, atopic dermatitis, osteoarthritis, canine parvovirus. Mostly for dogs
what is tolerance
immunological unresponsiveness to an antigen (tolerogen)
what is autoimmunity
breakdown in tolerance to self antigens leading to an adaptive immune response to self
what are two ways tolerance is acheived
- negative selection (exclusion) of self reactive T and B cells
- T regulatory function
what is central tolerance
clonal deletion or negative selection during initial B and T cell development
what is peripheral tolerance
acitvation of induced cell death if a B or T cell has a signal 2 response to an auto-antigen but no signal 1
anergy if there is no co-stimulation
tolerogens vs immunogens
tolerogens:
- present in generative organs
- no second signal in costimulation
- longlived
Immunogens:
- not in generative organs
- give costimulation (second signal)
- shortlived
three reasons for autoimmunity
- genetic predisposition
- environmental triggers
- other factors (hormones, stress, neoplasia)
what are some mechanism of autoimmunity
-autoreactive T cells get out of thymus
- failure of peripheral tolerance
- release of sequestered antigen
-polyclonal activation
-molecular mimicry
what is genetic predisposition of autoimmunity linked to
MHC alleles with inbreeding
what are some environmental triggers of autoimmunity
inflammation
infection
drugs
UV
what is a sequestered antigen
antigens that cannot interact with immune system during development as they are anatomically sequestered. lymphocytes specific for sequestered antigens are not deleted
what is molecular mimicry
sequence similarities between foreign and self-peptides is sufficient to result in cross activation of autoreactive T or B cells by pathogen derived peptides
what is poly clonal activation
T cells unrelated to antigen being presented get activated
what is the autoimmune component to diabetes mellitus
CTLs infiltrate the pancrease and activate macrophages, then autoantibodies are released, leading to complement activation or ADCC by NK cells. eventually this leads to a DTH response in which there is an autoimmune attack against beta cells in the pancreas
