Which of these is false regarding cytokines:
Mediators of inflammation
Does not mediate specific reactions
Produced by macrophages
Are soluble proteins
Cytokines mediate their effects by binding to specific high-affinity receptors on their target cells. Specific cytokines mediate specific reactions.

Other important characteristics of cytokines

Cytokines are soluble proteins produced by a wide variety of hematopoietic and non-hematopoietic cells.
They are short acting.

They are required for

Regulation of growth
Activation of the immune system
Mediation of inflammatory response