Learning Objective
Describe the major cytokines, their cellular sources, functions, and relevance to immunity, inflammation, and pathology.
Activity
Cytokines Secreted by Macrophages / Innate Immune Cells
| Cytokine |
Major Function |
Mnemonic / Notes |
| IL-1 |
Fever, acute inflammation; activates endothelium for adhesion molecules; induces chemokine secretion; osteoclast-activating factor |
Hot T-bone stEAK: IL-1 = fever (hot) |
| IL-6 |
Fever stimulates acute-phase protein production |
Part of “hot” acute phase response |
| TNF-α |
Activates endothelium, recruits WBCs, vascular leak; cachexia in malignancy; maintains granulomas in TB |
Mediates fever & sepsis along with IL-1, IL-6 |
| IL-8 |
Major neutrophil chemotactic factor |
Clean up on aisle 8 |
| IL-12 |
Induces Th1 differentiation; activates NK cells; facilitates granuloma formation |
Bridges innate and adaptive immunity |
Cytokines Secreted by T Cells
| Cytokine |
Major Function |
Mnemonic / Notes |
| IL-2 |
Stimulates proliferation of helper, cytotoxic, and regulatory T cells; activates NK cells |
Hot T-bone stEAK: IL-2 = T-cell growth |
| IL-3 |
Supports bone marrow stem cell growth; functions like GM-CSF |
Stimulates multiple leukocyte lineages |
| IFN-γ |
Secreted by Th1 and NK cells; activates macrophages; promotes IgG switching; inhibits Th2 differentiation; increases MHC expression |
From Th1 cells: activates macrophages, granuloma formation |
Cytokines Secreted by Th2 Cells
| Cytokine |
Major Function |
Mnemonic / Notes |
| IL-4 |
Differentiation of Th cells to Th2 promotes B cell growth; class switching to IgE & IgG |
Ain’t too proud 2 BEG 4 help: B = IgE, E = IgG |
| IL-5 |
Promotes B cell growth; class switching to IgA; eosinophil growth & differentiation |
I have 5 BAEs: B = B cells, A = IgA, E = Eosinophils |
| IL-10 |
Attenuates inflammatory response; decreases MHC II and Th1 cytokines; inhibits activated macrophages & dendritic cells |
Anti-inflammatory; secreted also by Tregs |
| IL-13 |
Promotes IgE production; alternative macrophage activation |
ThirtEEn promotes IgE |
Activity
