Immunology Cytokines

Th1 function

- cell mediated and antiviral

- inhibit Th2 functions

- enhance macrophages

- promotes Ig class switch: IgG

Th1 cytokines

IL-2, IL-12, IFN-gamma

IL-2

Th1 cytokine

- Induces T cell proliferation and supports their growth

- Enhances cytotoxic activity of NK cells and CTL

IL-12

Th1 cytokine

- Tells Th0 to become Th1

- produced by APC

- inducer of IFN-gamma

- promotes Th1

IFN-gamma

Th1 cytokine

- proinflammatory

- produced by and enhances macrophages

- inhibits Th2

- Enhances cytotoxic activity of CTL and NK cells

- Class switch: IgG

Th2 function

- humoral and antiparasitic (basophil, mast cells, B cells, and eosinophils)

- inhibits Th1

- involved in development of allergies

- inhibit Th1, CTL, NK, and Th17 function

Th2 cytokines

IL-4, IL-5, IL-6, IL-10

IL-4 and IL-5

Th2 cytokines

- Produced by TH2 cells, and mast cells

- Promotes proliferation and differentiation of B Cells

- Induces Ig class switch: IgE and IgG1

- Promotes TH2 proliferation and mast cell growth

- Receptor expressed on Th0 cells and will phenotypically change them to Th2 cells.

IL-6

Th2 cytokine

- aids in B cell development

- mostly proinflammatory

- pleiotropic

- wound healing

- longer half-life

IL-10

Th2 and Treg cytokine

- anti-inflammatory and mucosal immunity

- role in tolerance

- regular Th2 functions

Th17 function

- inflammatory and antibacterial and antifungal

- enhance neutrophil response

Th17 cytokines

IL-17

IL-17

Th17 cytokine

- proinflammatory

- multiple types of IL-17 with similar structures

- mycobacterial surveillance

- autoimmune diseases

- allergy

Tfh function

- T dependent antibody response

- Goes to lymphoid follicle after differentiation

- Activates B cells (T dependent antibody production)

- B+Tfh results in formation of germinal center

- Promotes class switch to all isotopes (like IgG, esp. IgG1) => “master regulator”

Tfh cytokines

IL-21

also produces IL-4 and induced by IL-6

Treg

• Anti-inflammatory; promotes mucosal immmunity

• Promote healing & tissue differentiation

• Suppress other immune responses

• Induce Ig class switch: Treg → TGF-β → IgA