Alterations in immune response Flashcards
what are the two arms of adaptive (acquired) immunity
1) humoral (B cells)
2) cellular (t vells)
what do humoral cells do?
produce antibodies for bacteria and viruses
what do cellular (t cells) do?
react directly with antigen (protein) on cell surface
- deal with viruses and cancer cells
what is hypersensitivity?
Excessive or inappropriate immune response to an antigen that results in disease or damaged to the host
- includes allergy, autoimmunity, and alloimmunity
- may be either antibody mediated (b cells) or cell mediated (t cells)
what is an allergy?
Harmful effects of hypersensitivity to environmental (exogenous) antigens
what is the def of autoimmunity?
Disturbance in the immunologic tolerance of self-antigens
- breakdown of self-tolerance
- body recognizes self-antigens as foreign
- cause isnt understood
what is the def of alloimmunity?
Immune reactions to tissues of another individual (transplant, graft rejection)
what is most likely to cause a type 1 allergy?
-Against environmental antigens (allergens)
which antibody does a type 1 allergy rely on?
IgE
what is an antigen that causes an allergic reaction called?
allergen
what happens after IgE has attached to the mast cell?
It is sensitized, when a second exposure happens, the antigen binds to the mast cell and cause it to degranulate, releasing no inflammatory mediators (histamine)
what does histamine do in an allergic reaction?
It binds to HI, and causes smooth muscles around bronchi to contract = airways get smaller =difficult to breathe, causing blood vessels to dialte. Allergen is more easily able to squeeze through blood vessels, causing edema, and can lead to hives
which systems are most affected by a type 1 allergy?
skin, respiratory, and GI tract
what are some manifestations of a type 1 allergy?
itching urticaria (hives) conjunctivitis (inflammation of conjunctiva (eye) rhinitis (inflammation of nose) edema GI cramps and malabsorption
what can happen in a type 1 allergy?
anaphylactic reaction (life threathening allergic reaction)
can people be genetically predisposed to an anaphylactic reaction?
yes (atopic)
what occurs inside the body during an anaphylactic reaction?
wheezing difficulty breathing increased heart rate hypotension (decreased bp) nausea, vomiting, diarrhea possible respiratory arrest or failure
what can be used to treat anaphylactic reaction?
first line: epinephrine (main tx)
other; corticosteriod, anithistatime
what does a type 2 hypersensitivity reaction rely on
IgG and IgM (produced by B cells)
is a type 2 allergy tissue-specific or cell-specific
tissue specific
how does a type 2 allergy happen?
When some self-reactive immune cells escape their primary lympoid organs (thymus for T cells, Bone marrow for B cells)
These self reactive cells cacn then attack healthy tissue
what do self reactive B cells produce?
IgM and IgG
how does a type 2 allergy cause damage to cells?
the making of a antibody-antigen complex initiates the compliment system which attracts neutrophils, which dump enzymes that are highly cytotoxic to the cell = tissue damage