Autoimmunity Flashcards
central tolerance
deletion of lymphocytes specific for self antigens in primary lymphoid organs
peripheral tolerance
deletion of lymphocytes that recognize self antigens in secondary lymphoid organs
central tolerance to tissue-specific antigens
individual organs of the body express tissue-specific antigens (retina, ovaries) –> AIRE will allow expression of these antigens in the thymus for deletion of tissue-reactive T cells
absence of AIRE
T cells reactive to tissue-specific antigens mature and leave the thymus
sequestered antigens
some self antigens are sequestered in specialized tissues and cannot be expressed in thymus or bone marrow so there will be no induction of self-tolerance –> exposure in periphery results in T cell activation
immunologically privileged sites
brain, eye, testis, uterus
molecular mimicry
viruses and bacteria possess antigenic determinants similar to normal host cell components so once effect is formed to these antigens, self antigens will now be attacked after activation
polyclonal B cell activation
viruses and bacteria can induce nonspecific polyclonal B cell activation, inducing proliferation of B cells to secrete IgM in absence of CD4 help; leads to activation of self-reactive B cells
type II hypersensitivity autoimmunity
antibodies to tissue antigens (usually some type of NT receptor)
examples of type II autoimmunity
hemolytic anemia, thrombocytopenic purpura, goodpasture’s syndrome, pemphigus, and rheumatic fever, grave’s, myasthenia gravis
goodpasture’s syndrome
antibodies towards to the basement membrane (type iv collagen) causes glomerulonephritis
grave’s disease
autoimmune B cells make antibodies to TSH receptor, stimulating thyroid hormone production
myasthenia gravis
antagonist antibodies to AchR prevent Ach from binding causing muscle weakness
type III hypersensitivity autoimmunity
antibodies to soluble antigens
type III autoimmune diseases
lupus and arthritis
