Immuno - Autoimmunity Review

drraythe's version from 2015-06-15 00:57


Question Answer
How does having an immune privileged site run a risk of auto-immunity?Usually places like the testes, lens of eye, brain, things inside cells like mitochondria, do not make contact w/ lymphocytes. If there is tissue damage, these cells are exposed, & since the body has never seen them, will form Abs against them. In short, damage to immune privileged site can cause exposure & Ab formation
Explain "molecular mimicry" autoimmune dzIf a self-cell shares epitopes w/ an Ag, the body might form an Ab against that epitope & attack itself
Explain "molecular alterations" autoimmune dzWhen an Ab binds to an Ag, it changes a little. Abs might change their conformation into to the changed Abs. (ex: rheumatoid arthritis)
Explain "loss of tolerance/regulation" autoimmune dzUsually the body makes a bunch of random T-cells, & then it kills off the ones that react to self. If there is a problem w/ the Thymus/receptor used to kill the bad T-cell, they will escape & then attack the body
Explain what is happening in canine rheumatoid arthritisMOLECULAR ALTERATIONS! (Ab binds to Ag, which changes the Ab. Abs are formed against the changed Ab.) THEN immune complexes form as more & more antiAb-Ab binding happens. Then the complexes have the macrophages release pro-inflammatory cytokines which have neutrophils enter & release enzymes which damages the cartilage
Explain what is happening in a milk allergy in cattleHYPERSENSITIVITY TYPE 1 RXN. Delayed milking causes an increase in pressure & forces milk protein (casein) into circulation, where Abs (IgE!!) are formed for a Th-2 response against the casein.
Explain immune-mediated cytopeniasTYPE 2 HYPERSENSITIVITY RXN (Abs to cell Ags). AutoAbs (or complement) against cell-surface Ags (can do coombs test)
Explain myasthenia gravisTYPE 2 HYPERSENSITIVITY RXN. (Abs to cell Ags) Abs against ACH receptor on mm cell (Abs block the receptors, signals don't get through) (2 grave to think about)
Explain lymphocytic thyroiditis in dogsTYPE 2 (Abs to cell Ags) & TYPE 4 (DTH-delayed Type hypersensitivity & CTLs -th-1 response, not Abs) HYPERSENSITIVTY RXN. Cytotoxic t-cells attack thyroid epi & Abs formed against T3, T4, & Thyroglobin (causes HYPOTHYROIDISM) - common in beagles, great danes, etc.
How would you confirm lymphocytic thyroiditis in dogs?Need to see Abs in serum & need biopsy to show characteristic lymphocytic infiltration (CTLs & ADCC-Antibody-Dependent Cell-Mediated Cytotoxicity at play here)
Explain pemphigus folieaceousAb attaches to adhesion proteins in the skin, which allows for activation of complement (Type two) tissue destruction (sloughing of keratanocytes) AB-AG INTERACTION ALLOWS FOR COMPLEMENT ACTIVATION (antibody binds to cell antigen & activates complement to damage tissue)
Explain SLE (systemic lupus erythematosis)TYPE 3 HYPERSENSITIVITY- autoAbs form immune complexes w/ self-antigens which can then cause inflammation. ABS TO NUCLEAR MATERIAL, SUCH AS DNA
Explain polymyositisTYPE IV HYPERSENSITIVITY. Has autoreactive T-cells & antibodies. Targeted destruction of myocytes expression MHC-1
Explain insulin-dependent Diabetes MellitusType-IV hypersensitivity. Immune system destroys insulin-secreting cells in the pancreas.
How can there be a genetic predisposition to autoimmune diseases?MHC genes are linked to almost every autoimmune disorder. Also probs w/ deleted or overexpressed genes. Having breeds = lack of genetic diversity = recessive genes expressed
What hypersensitivity is milk allergy?Type 1 (think allergies)
What hypersensitivity is immune-mediated cytopenias?Type 2 (Abs to cell Ags)
What hypersensitivity is myasthenia gravis?Type 2 (Abs to cell Ags)
What hypersensitivity is lymphocytic thyroiditis?Type 2+4 (Abs to cell Ags & also delayed Type Hypersensitivity & Cytotoxic T lymphocytes, ie: Th-1 response)
What hypersensitivity is pemphigus folieaceous?Type 2 (Abs to Ags)
What hypersensitivity is SLE?(Systemic lupus erythematosus) Type 3 (autoantibodies form immune complexes w/ self-antigens)
What hypersensitivity is polymyositis?Type 4 (delayed Type hypersensitivity & cytotoxic t lymphocytes, ie: Th-1 response)
Self-antigen in milk allergy?Casein
Self-antigen in immune-mediated cytopenias?RBC, thrombocyte, leukocyte
Self-antigen in myasthenia gravis?ACH receptor
Self-antigen in lymphocytic thyroiditis?Type 4 part = CTLs attack thyroid epi. Type 2 part = Abs to T3+4
Self-antigen in pemphigus?Adhesion protein
Self-antigen in SLE?Nuclear material, usually DNA
Self-antigen in polymyositis?Myocytes w/ MHC-1
What are the three Type 4 hypersensitivity diseases?Lymphocytic thyroiditis has a 4 component, polymyositis, & insulin dependent Diabetes
What are the 2 Type 3 hypersensitivity disease?SLE (lupus), & rheumatoid arthritis
How do you treat most autoimmune disorders?Immunosuppressant drugs
What kind of immunosuppressive drugs do we use? Ex’s?Glucocorticoids (prednisone, dexamethasone)

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