"Cytokines (Greek cyto-, cell; and -kinos, movement)
are small cell-signaling protein molecules that are
secreted by numerous cells and are a category of signaling
molecules used extensively in intercellular communication.
Cytokines can be classified as proteins, peptides, or
glycoproteins; the term "cytokine" encompasses
a large and diverse family of regulators produced throughout
the body by cells of diverse embryological origin...."