NEET BIOLOGY

Detailed explanation-1: -Interferons are proteins synthesized in various host cells, encoded by the host genes, in response to double-stranded RNA (dsRNA). Interferon circulates and has the role to protect uninfected cells by inhibiting viral protein synthesis.

Detailed explanation-2: -The correct answer is Virus. Interferons are synthesized in response to the Virus. Cells infected by viruses produce interferon which is an antiviral protein.

Detailed explanation-3: -Interferons (IFNs)-the body’s first line of antiviral defence-are cytokines that are secreted by host cells in response to virus infection. By inducing the expression of hundreds of IFN-stimulated genes, several of which have antiviral functions, IFNs block virus replication at many levels.

Detailed explanation-4: -Interferons act via autocrine and paracrine pathways to induce an antiviral state in infected cells and in neighboring cells containing interferon receptors. Interferons are the frontline defenders against viral infection and their primary function is to locally restrict viral propagation.

Detailed explanation-5: -Type I interferon (IFN-alpha and IFN-beta) is secreted by virus-infected cells while type II, immune or gamma interferon (IFN-gamma) is mainly secreted by T cells, natural killer (NK) cells and macrophages.