Interleukin-4 is a member of the cytokine regulators of the immune system. Cytokines are proteins produced by the genes they include interleukins, tumor necrosis factor and interferons. Some cytokines clearly promote inflammation and are called proinflammatory cytokines, whereas other cytokines suppress the activity of proinflammatory cytokines and are called anti-inflammatory cytokines. In summary, the cytokines both promote and prevent inflammation. Some fight pathogens while others shut down defense against pathogens.
Cytokines modulate the numerous immune functions.
There is growing evidence that viruses have used strategy of that type to overcome host defense during the course of their evolution. However, genetic modification will greatly hasten the mixing of regulatory cellular genes and virus genes. Gene therapy experiments may create dangerous pathogens , but can crop genetic engineering lead to creation of dangerous pathogens. Cytokine genes from human and animals have been extensively introduced intomcrop plants which have been tested in the open environment in field crops. Such experiments could easily lead to production of insect baculoviruses bearing human genes by recombination between the human genes in crops and the insect viruses.