cytokine secretion trait interferon secretion trait IFN secretion Any measurable or observable characteristic related to the controlled release of proteins secreted by vertebrate cells in response to a wide variety of inducers; they confer resistance against many different viruses, inhibit proliferation of normal and malignant cells, impede multiplication of intracellular parasites, enhance macrophage and granulocyte phagocytosis, augment natural killer cell activity, and show several other immunomodulatory functions. Trait.ontology VT:0008555