Interferons refer to small proteins discharged by the stimulated lymphocytes, virus-affected tissues, and macrophages. They activate antiviral proteins in the cytoplasm of the nearby cells. They do not inhibit the entry of viruses, however, they interfere with the replication of viruses. It also instigates the activities of natural killer cells and macrophages. The three types of interferons are alpha interferons, beta interferons, and gamma interferons.
The complement system refers to a segment of the immune system, which elevates or complements the tendency of the phagocytic cells and antibodies to clear the destructed cells and microbes from an organism, attacks the pathogen's plasma membrane, and promotes inflammation.