Micro Cytokines Flashcards
cytokines secreted by lymphocytes
Lymphokines
cytokines secreted by monocytes/macrophages
Monokines
chemotactic cytokines, involved in
inflammation
Chemokines
secreted by leukocytes, act on leukocytes
Interleukins
Property of cytokines:
- Cytokines bind to specific receptors on target cell membranes, trigger signal-transduction pathways and alter gene expression
- Autocrine: cytokines act on the same cell its released from (Ex: IL2)
- Paracrine: cytokines act on a nearby cell (most common)
- Endocrine: cytokines goes into the circulation and bind to a distant cell
- A single cytokine can have different effects
- Different cytokines can have the same effect
- Cytokines can work in synergy
- The effect of one cytokine can inhibit another
- Cytokines can network
General Functions of cytokines:
Intercellular messenger molecules
- Cellular & humoral immunity
- Induction of inflammatory responses
- Regulation of hematopoiesis
- Cellular proliferation and differentiation
- Growth inhibition, apoptosis
- Wound healing
Induction of Humoral Immunity:
- Activation
- Division
- Differentiation
Ags are Internalized, Processed and Presented by APC → MHC+Epitope complex is recognized by T cells → Specific Th cells become activated →
→Th1 → HELP for T cells → T cells activate other T
cells and macrophages
→Th2 →HELP for B cells → B cells produce antibodies
Cytokines are: pro-inflammatory →
Act to make disease worse
IL-1, TNFa, IL-6
Cytokines are: Anti-inflammatory →
Reduce inflammation and promote healing
IL-10, IL-4, TGF
Regulation of hematopoiesis
Differentiation to different kinds of blood cells depends on the type of cytokine
Immunopathological Reactions- Cytotoxicity
Cytotoxicity - when important cells are killed for example neurons can not be regenerated so when cytokines stimulate a macrophage to target an infected neuron this neuron is lost
Immunopathological Reactions- Chronic Inflammation
Chronic Inflammation when the immune response does not stop because of continuous cytokine release and T cells activate macrophages causing joint damage as in rheumatoid arthritis Or when TNF causes cytotoxicity that kills the cells of pancreas causing diabetes
Immunopathological Reactions- Granuloma
Granuloma happens when cell is not able to eliminate infection (like intracellular tuberculosis) and cells are attracted to surround the infected cell to stop the spread of bacteria, however if the granuloma becomes large it is harmful or when the granuloma happens in a place like the brain it it harmful
Immunopathological Reactions- Excessive cytokine release
When the cytokines are released because of a an infection then spread through the blood circulation and affect different parts of the body and cause a multiple organ system failure
