What are the types of cytokines?

There are four main types of cytokines. 

1. Interferons – These are released by the host’s immune system cells in response to an invasion by a toxic organism. Interferons don’t suppress or kill the invader directly. Instead they work by stimulating the production of antiviral proteins through cell surface receptors. They also strengthen the action of macrophages, T lymphocytes, and natural killer cells, boosting the immune system’s antiviral ability. 
2. Chemokines – Chemokines play a key role in chemotaxis. They act as signals that guide specific immune cells towards the site of invasion. There are about 50 different types of chemokines. 
3. Interleukins – Interleukins refer to a group of cytokines with highly complex immunomodulatory functions including cell proliferation and growth, development of B cells, activation of dendritic cells and T-cells, and production of antibodies.  They primarily work as antiviral cytokines and can be synthesized by almost all cells in response to a viral infection. 
4. Tumor Necrosis Factor (TNF) – This is a multifunctional group of cytokines involved in various pathological and physiological processes. Tumor necrosis factor is a proinflammatory cytokine. It is released by inflammatory cells and is thought to be involved in inflammation-associated carcinogenesis. TNF plays crucial roles in a wide range of cellular events such as cell proliferation, differentiation, survival, and death.