Autoimmunity/ immunodeficiency Flashcards
___________________ results from self reactive B and T cells
Autoimmunity
How can a normal immune response lead to autoimmunity
Previously hidden antigens
- > tissue damage leading to exposure of intracellular molecule s
- > molecular structural alterations
- > newly synthesized antigens
Molecular mimicry
-> microbe has similar antigens to self
How does an abnormal immune response lead to autoimmunity?
Failure of regulatory control
- > failure of apoptosis
- > viral infections - cytokine production leading to inflammatory and Tcell activation
- > microchimerism (eg scleroderma in women with fetal cells)
How can cross reactions with self antigens lead to autoimmunity ?
Normally a Tcell does not bind a self antigen -> no activation of immune response
Foreign antigen that is similar to a self antigen is processed and presented to a Tcell -> which activates the B cell -> Bcell produces antibodies that are reactive against both foreign and self antigens
Viruses can activate an autoimmune response by what two pathways?
Molecular mimicry
Bystander activation
Describe molecular mimicry by virus lead to autoimmune response?
Virus coats itself in host self-antigens
Virus processed by APC -> self antigen is presented to Tcell
Leads to cross reaction
What is the bystander activation and how does it lead to autoimmunity?
An infection leads to Tcell production of cytokines
Cytokines cause activation of resting Tcells -> activated Tcells produce non specific activation of immune cells
What are predisposing factors to autoimmunity?
Genetics Breed Internal microflora Type 1 hypersensitivity -> milk allergy Type 2 hypersensitivity Type 3 hypersensitivity Type 4 hypersensitivity
Production of antibodies against triiodothyronine and thyroxine produces ___________
Autoimmune thyroiditis
An insulin depended diabetes mellitus can be due to antibodies against _______________________
Glutamic acid decarboxylase
A pemphigus foliacus on the surface of the skin is due to antibodies against _______________
Squamous cell desmosomes
A pemphigus vulgaris in the epidermis, superficial to the BM is due to antibodies against _____________
Desmosomes
A bulbous pemphigoid in the dermis, deep to the BM is due to antibodies against ________________
Type XVII collagen
What is the difference between extravascular and intravascular hemolysis?
Extravasular - antibody bound to RBC is bound by macrophage, phagocytosed and lied within the cell
Intravascular- antibody bound to RBC activates complement system and is lysed within the blood stream
What is the pathogenesis of myasthenia gravis?
How can it be treated
ACh receptors are destroyed preventing neurotransmitter transmission
Anticholinesterase drugs are used to prevent recycling of ACh -> ACh remains in neuromuscular junction -> enhancing signal transmission
What are the two most common autoimmune diseases?
Rheumatoid arthritis
Systemic lupus erythematosus
During infection, genetics or defect in apoptosis leads to abnormalities in __________ cell which causes excessive B cell production of _____________
Tcells; antibodies
In systemic lupis erythematosus, autoantibodies can be produced against?
Nucleic acids
Organ specific -RBC, muscle, skin
What can lead to an abnormal immune response in joints?
Abnormal Ig glycosylation
Genetics
Infectious agents
What T cell promotes inflammation in rheumatoid arthritis
Th17 cell
Antibodies bind IgG, type II collagen, and glycosaminoglycans to form complexes which causes _______________ accumulation leading to tissue destruction of the joints
Neutrophil
Type III hypersensitivity
_______________ is the impairment of part or parts of the immune system that renders the patients more susceptible to infectious disease
Immunodeficiency
What are the two types of immunodeficiency ?
Primary-> mutation of a gene (inherited)
Secondary-> due to age, infection, medical therapy, or chronic disease (acquired)
What signalments can be used to diagnose primary immunodeficiencies?
Breed
Occurring in young littermates
Chronic recurring infection/ infection in multiple body sites
Failure to respond to antibiotic therapy and vaccination
Infection by environmental saphrophytes (normally nonpathogenic)
Persistent lymphopenia
What are the levels of primary immunodeficiency
Pluripotent stem cells Committed stem cells Tcell development Bcell development Bcell maturation to plasma cell Ig production Phagocyte production Complement production
Severe combined immunodeficiency is a ____________ immunodeficiency caused by a deficit in?
Primary
TCR and BCR defects
_____________ is characterized by a lack of T lymphocytes and poor development of hair coat
Thymic aplasia
Primary immunodeficiency
How do zinc associated disorders lead to immunodeficiency?
Zinc is important in normal activity of T cells -> lymphocyte dysfunction
Eg Acrodermatitis in bull terriers
A neutrophil disorder is a primary immunodeficiency that results from failure to produce?
Functional phagocytic cells
What level of primary immunodeficicy is the worst and results in the death of an animal at a very young age?
Failure of pluripotent stem cells
Selective immunoglobulin deficiency results from a low level of _______ resulting in mild-chronic recurring mucosal infections
IgA
There is no complement activation in a _____ deficiency
C3
Failure to regulate activation of the complement pathway is caused by _______ deficiency
Factor H
Is primary or secondary immunodeficiency more common?
Secondary
What can cause medical immunosuppression?
Chemotherapy Immunosuppressive therapy (eg transplants)
What infections can lead to secondary immunodeficiency ?
FIV or FeLV
Affect WBC- decreased function
What is immunosenesence?
Gradual deterioration of the immune system due to old age
CD4 Tcells decrease -> decreased triggering of immune response
CD8 Tcells increase
Susceptible to infection and autoimmune disease, and neoplasia
