Diseases of Immune system Flashcards
define innate immunity
mechanisms that react to infections before infection to recognize and combat microbes
define adaptive immunity
mechanisms stimulated by microbes that recognize microbial/nonmicrobial substances
what are the major components in innate immunity
mucose membranes, phagocytic cells, NK cells, and plasma proteins
what are major components in adaptive immunity
lymphocytes and their products
what immunity involves memory
adaptive
what are the two types of adaptive immune responses
- antibody-mediated immunity (humoral immunity)
- cell mediated immunity (cellular immunity)
what lymphocyte is found in antibody mediated immunity
B lymphocytes
what lymphocyte is found in cell mediated immunity
T lymphocytes
what is the function of antibody mediated immunity
antibodies provide protection vs extracellular microbes in body fluids
what is the function of cell mediated immunity
T cells provide protection vs intracellular microbes by killing infected cells or activating phagocytic cells by cytokines
naturally acquired active immunity is defined as
antigens entering body naturally; body induces antibodies and specialized lymphocytes
naturally acquired passive immunity is defined as
antibodies passed on from mother to fetus
artificially acquired active immunity is defined as
antigens introduced by vaccines; body produces antibodies and specialized lymphocytes
artificially acquired passive immunity is defined as
preformed antibodies in immune serum are introduced by injection
how are T lymphocytes activated in cell mediated immunity
Naive T lymphocytes are activated by antigen
what is the mechanism of action seen in cell mediated immunity
active T lymphocytes proliferate and differentiate to site where antigen is
hypersensitivity is defined as
reflection of excessive or aberrant immune response
what do CD4+ helper T cells secrete
they secrete cytokine IL-2 which stimulates proliferation
T cells express CD40L that engages with
CD40 that activates macrophages and B cells
in antibody mediated immunity, B lymphocytes proliferate and differentiate into
plasma cells and secrete antibodies
what are the different pathways that antibody mediated immunity can result in
- neutralization of microbes and toxins
- opsonization and phagocytosis of microbes
- antibody dependent cellular cytotoxicity (NK cell)
- activation of complement activation
hypersensitivity reaction type 1 is characterized by
- immediate hypersensitivity
- manifests in minutes
- interaction of antigen with IgE on surface of mast cells
what are the three phases in type 1 hypersensitivity
- sensitization phase
- activation phase (early allergic response)
- late allergic response
once mast cells are activated, what occurs
they release chemical mediates
what is the immediate response seen in mast cell activation
- vasodilation
- vascular leakage
- smooth muscle spasm
what is late phase reaction seen in mast cell activation
- leukocyte inflitration
- epithelial damage
- bronchospasm
hypersensitivity reaction type 2 disease are caused by
antibodies directed against target antigens on surface of cells
type 2 hypersensitivity involves what antibodies that causes what
IgG or IgM that induces damage to self cells
mechanism of antibody mediated diseases are
- opsonization and phagocytosis
- inflammation
- antibody mediated cellular dysfunction
in hypersensitivity reaction type 3 what occurs
antigen-antibody deposit in blood vessels resulting in complement activation and acute inflammation
what are the phases of disease in hypersensitivity reaction type 3
- formation of Ag-Ab complexes in the circulation
- deposition of immune complexes in various tissues
- inflammation reaction and destruction of host tissue
what is mechanism of cytokine-mediated inflammation
CD4+ T cells activated by exposure to antigen and differentiate into TH1 & TH17 effector cells. Subsequent exposure results in cytokine secretion causing inflammation
self tolerance is the
lack of immune responsiveness to one’s own antigens
autoimmunity results from
failure to self tolerance
in central tolerance what occurs
immature lymphocytes that recognize self antigenes killed by apoptosis; in B cells, they switch to new antigen receptors that are not self reactive
in peripheral tolerance what occurs
mature lymphocytes that recognize self antigens become inactive, suppressed or die
what are common autoimmune disease
- systemic lupus erythematosus
- rheumatoid arthritis
rejection in transplants involves
both cell and antibody mediated reactions
what are the different types of transplants
autograft, allograft, isograft, xenograft
what is the function of Helper T lymphocytes
stimulate B lymphocytes to make antibodies
what is the function of cytotoxic T lymphocytes
kill infected cells
what is the function of regulatory T lymphocytes
limit immune response and prevent reaction against self antigent
what is the function of B lymphocytes
produce antibody molecules
what is the function of dendritic cells
they are antigen presenting cells that initiate T cell response
what different functions do macrophages have
- phagocytosized microbes and protein antigens present peptide fragments to T cells
what is the function of NK cells
destroy virus infected cells and tumor cells
autograft are
transplant of tissue to the same person
allograft are
transplants of organ/tissue between two genetically non identical members
isograft are
transplants from donor to genetically identical recepient
xenograft are
transplant of organs/tissue from one species to another
what is mechanism of T-cell mediated cytotoxicity
CD8+ TCLs recognize antigen and kill cells
what is mechanism in direct recognition of allograft
Host T cells recognize allogenic MHC on graft cells
what is mechanism in indirect recognition of allograft
Host CD4+ T cells recognize donor MHC
