Interferons are the sustances secreted by the virally infected cells to protect the surrounding cells from infection.
Cytokines are the signalling molecules produced by the cells during an immune response. Interferons are one such cytokines which are a group of signalling proteins produced by the infected host cells.
A virus infected cells can release numerous viral particals that can infect the neighbouring cells. The production of these interferons by the infected cell signals the surrounding cells to increase their immunity against the virus. In response to interferons, the cells produce ceratin enzymes that destroy the RNA , interfere and inhibit the process of protein synthesis of the viral particles and the infected host cells. Thus eliminating them from the body.