Immune cells Flashcards
development of TH1 cells is triggered by what transcription factors
STAT4 and T-bet
development of TH2 cells is triggered by what transcription factors
STAT6 and GATA
what triggers differentiation of TH1 cells
IL-12
what triggers differentiation of TH2 cells
IL-4
what do TH1 cells release
INF-γ, IL-2 and TNF-β
what do TH2 cells release
IL-4, IL-5, IL-6, IL-10 and IL-13
what are the main effector cells of TH1 cells and what do they activate
Macrophages, cytotoxic T cells, B cells - mainly cell mediated immunity
what are the main effector cells of TH2 cells and what do they activate
B cells - activating humoral immunity
what does overactivation of TH1 cells cause
hypersensitivity and autoimmunity
what does overactivation of TH2 cells cause
allergy and hypersensitivity
what are the two receptors of IgE antibodies
1 Fc epsilon receptor 1 (High affinity)
2 Fc epsilon receptor 2 (aka CD23) (Low affinity)
where is the FcεRI found and what does binding of antigens to IgE-FcεRI lead to
expression is inducible in eosinophils by IL-5, is constitutively expressed in mast cells and basophils
Binding of antigens to IgE already bound by the FcεRI cells causes cross-linking of the bound IgE and the aggregation of the FcεRI,
Inducing signaling cascade -> leading to the degranulation
what does FcεRII do
Regulates IgE levels by competing and breaking the cycle at B cell and Eosinophil (stops degranulation)
(only when IgE levels high)
eosinophils make up ___ of WBCs
1%
basophils make up ___ of WBCs
0.1%
what are eosinophils
white blood cells that contain small granules that release chemical mediators
(eosinophilia)high levels of eosinophils in your blood and tissues usually indicates
a parasitic infection, an allergic reaction or cancer.
eosinophils cause IgE/FcεRI mediated release of what two things
– eosinophil peroxidase (cytotoxic)
– major basic protein (cytotoxic and induces mast cell and basophil degranulation)
how long do eosinophils persist in circulation for and how long can they remain in the tissues
Eosinophils persist in the circulation for 8–12 hours, and can survive in tissue for 8–12 days in the absence of stimulation.
what are basophils
a types of white blood cell that release granules to fight fungal or bacterial infections and viruses.
what do basophils release
– pre-formed mediators (from the granules): serine proteases, histamine, serotonin, heparin
– newly formed lipid mediators: prostaglandin D2, leukotriene C4, platelet-activating factor
– newly formed cytokines: eosinophil chemotactic factor, Interleukin 4
what is the critical cytokine in the development and production of IgE
IL-4
what does heparin do
anti-coagulation - decreases clotting ability in blood
