Autoimmune diseases II Flashcards
In autoimmune disease, what is tolerance lost to
self-antigens
What immune responses are directed towards normal body components in AID
chronic adaptive immune responses
2 things AID’s can do to cells/tissues
destroy or alter their functions
antigens
molecules or molecular fragments that can be bound by an MHC molecule and presented to a T-cell receptor
autoantigens
self-antigens (an antigenic component / amino acid sequence) of the body that can provoke an immune response by the individual’s own immune system
2 types of inappropriate autoimmune responses to self-antigens
humoral mechanisms - B-cells and antibodies
cell-mediated mechanisms - T-cells and cytokines
whats the function of b cells
Create antibody proteins
What activates b cells to produce antibodies (produced when the t helper cell receptor is activated)
cytokines
clonal selection
immune cells recognize and respond to specific antigens by producing clones of cells that are specific for that antigen.
in autoimmune disorders, clonal selection refers to the expansion of autoreactive clones of B or T cells that recognize self-antigens
central tolerance
Regulation of B- & T-cells proliferating in the thymus & bone marrow. they are un-reactive to self-antigen
what can cause central tolerance to be disrupted in autoimmune disease, leading to the development of autoreactive immune cells
genetic mutations or viral infections
what selects and eliminates auto-reactive of T-cells in central tolerance
the thymus
what does the thymus do to T-cells with high binding
for self-antigens
negatively selects, and induces apoptosis to them
Thymocytes
immature T cells derived from stem cells, that develop in the thymus gland
what part of the thymus contains only mature single- positive T cells, which leave and enter the bloodstream
medulla
what Thymocytes are eliminated or inactivated through negative selection
Those that recognize self-antigens too strongly
how can Autoimmune T-cells can be activated in a non-specific way by infection
inflammation/reduced regulation by cytokines
Inappropriate expression of what activates B- or cytotoxic T-cells
class II MHC
pancreatic b-cells express high levels of class II MHC in what disease
diabetes
What release by T cells do viruses promote which can increase class II MHC expression and help induce an autoimmune disease following a viral infection
Interferon-g release
whats Interferon-g (IFN-g)
a type of cytokine produced by activated T cells and natural killer (NK) cells
what does IFN-g contribute to in AID
development of chronic inflammation and tissue damage
where do B cells that successfully pass central tolerance checkpoints leave the bone marrow and travel to to be subjected to further tolerance mechanisms
the spleen
what has to be available when autoreactive B-cells migrate to the T cell area of secondary lymphoid tissues to cause disease
T cells
What transcription factor plays a crucial role in preventing the development of autoimmune diseases
AIRE (Autoimmune Regulator)
what disorders are due to mutations in the AIRE gene
Autoimmune Polyendocrinopathy Syndrome Type I
in Autoimmune Polyendocrinopathy Syndrome Type I disorders, what don’t function properly
multiple endocrine glands (parathyroid and adrenal)
what cells (regulatory elements) are critical in maintaining immune tolerance and homeostasis of the immune system
FOXP3+ regulatory T (Treg) cells
3 things tregs can express
Express CD4/CD25 & FoxP3
whats foxp3 crucial in
immune suppression
4 mechanisms treg cells use
inhibitory cytokines
cytolysis
metabolic disruption
targeting dendritic cells
4 mechanisms treg cells use
inhibitory cytokines
cytolysis
metabolic disruption
targeting dendritic cells
what is peripheral tolerance
Immunological tolerance developed after autoreactive T and B cells matures and enter the periphery. It enables the immune system to recognize and tolerate self-antigens or non-harmful foreign antigens in the body.
immunological ignorance
