Cytokines

What are cytokines?

a large group of molecules involved in cellular signalling

What are autocrines?

cytokines that affect the cell it was secreted by originally

What are paracrines?

cytokines that affect neighboring cells

What are endocrines?

cytokines that affect distant cells

What are four cytokine functions?

1. regulate the intensity and duration of immune responses

2. stimulate, activate, inhibit, differentiate cells

3. stimulate antibody secretion

4. stimulate other cytokines

What is pleiotropy?

how a cytokine can affect different cells in different ways

What is redundancy?

How two or more cytokines can exert similar functions

What is synergy?

How combined effects of cytokines can be greater than one

What is antagonism?

How reduced effects of cytokines in combination occur

What is cascade induction?

how a cytokine induces another cytokine

What is a cytokine storm?

when WBCs release cytokines all at once, usually occurs as a result of acute distress or systemic issues

What are interleukins?

IL are cytokines that are made by leukocytes for communication

• Fx: to induce inflammation

What are interferons?

cytokines produced by T-cells that inhibit viral synthesis

What are lymphokines?

cytokines secreted by lymphocytes

What are monokines?

cytokines secreted by monocytes or macrophages

What are the three classes of IFN? What are their fx?

alpha: inhibit viral replication

beta: inhibit viral replication

gamma: activate macrophages and stimulate Ab production

What is tumor necrosis factor?

TNF regulates acute inflammation of gram negative bacteria and infectious microbes

What is colony stimulating factor?

CSF stimulates the growth of WBCs or RBCs from the bone marrow

What is stem cell factor?

Compound that interacts with a tyrosine-kinase membrane receptor to cause bone marrow to respond to CSF

What are chemokines?

cytokines with chemotactic activities

• migration inhibiting factor: prevent macrophages from migrating elsewhere

• macrophage chemotaxin: attract macrophages

• soluble immune response suppressors: stop Ab production