Cytokines Flashcards
What is a Cytokine
Communicating proteins
Bind to autocrine,paracrine and endocrine cells
Regulate immune responses
Alter gene expression
Can be pleiotropic
Which molecules are cytokines
IL
Monokines
Lymphokines
Chemokines
Chemical structure of cytokines
Low molecular weight proteins
High affinity for receptors
Active in picomole amounts
What is the action of cytokines
Autocrine
Paracrine
Endocrine
Pleiotropy
Affects multiple cell types
Ex: IL-4 effects B cells, Thymocyte and mast cells for proliferation
Redundancy
Multiple cytokines affects cells of the same type
Ex: IL-2,IL-4,IL-5 all effect B cell for proliferation
Synergestic
Cytokines acting in concert on the same cell
Ex: IL-4 + IL-5 effect B cell to induce class switch to IgE
Antagonistic
Competing cytokines
IL-4 effects B cell to class switch to IgE
IFN-y effects B cell to block the effects of IL-4
Cascade induction of Activated T helper cells
Activated helper T cell— IFN-y— Macrophage— IL-12 — activated T helper cells— IFN-y, TNF ,IL-2 and other cytokines
Where do cytokines coming from
Macrophage
Granulocyte
Fibroblast
Endo cells
Mast cells
Lymphocytes
Produced also by non immune cells= fibroblasts,endo cells
Cytokine interactions
Direct contact
Release of soluble mediators
Innate immunity cells
Monocytes
DC cells
Macrophages
Neutrophils
NK cells
Megakaryocytes
Granulocytes
All of them do differentiation
Adaptive immunity cells
TC cells
Tree cells
TH1 cells
TH2 cells
B cells
Plasma cells
Role of cytokines in innate immunity
Inducing inflammation
Inhibiting viral replication
Promoting T cell responses
Limiting innate immune responses
Main cell source of TNF
Macrophages
T cells
Cellular targets and biological effects of TNF
Endo cells= inflammation, coagulation
Neutrophils = Activation
Hypothalamus = Fever, muscle and fat catabolism
Many cell types= apoptosis
Main source of IL-6
Macrophages
Endo cells
T cells
Cellular targets and biological effects of IL-6
Liver= synthesis of acute-phase proteins
B cells= proliferation of ab-producing cells
T cells= T helper 17 differentiation
Cellular targets and biological effects of IL-15
NK cells= proliferation
T cells= proliferation of memory CD8 cells
TNF mainly produced by
Macrophages
DCs
TNF is mediator of
Acute inflammatory response to bacteria and other infectious microbes
IL-1 şs the mediator of
Acute inflammatory response
Major cellular source of IL-1
Activated mononuclear phagocytes — Macrophages, Neutrophils, Epi cells, Endo cells
IL-6 is an important cytokine in
*Acute inflammatory responses
Induces the synthesis of acute phase reactants by liver
Stimulates neutrophil production in BM
Promotes differentiation of IL-17 producing helper cells
** Rheumatoid arthritis
Cytokines that have a multiple local and systemic inflammatory effects
TNF
IL-1
IL-6
*Functions of IL-2
Stimulates the survival, proliferation and differentiation of ag-activated T cells
Required for the survival and function of regulatory T cells
Effector T cells
Defining cytokines
Principal target cells
Are used for Helminths?
Effector T cell= TH2
Cytokine= IL-4,IL-5,IL-13
Target cells= Eosinophils
