Alpha and beta interferons are produced by virus-infected cells during the peak of virus replication 2-3 days post-infection. The enveloped RNA viruses are especially good at stimulating interferon. Gamma interferon is produced by dividing T cells and activated macrophages. It is much more potent than alpha and beta interferon and has a very important role in downgrading virus translation and upgrading MHC turnover for antigen presentation.

Macrophages

Macrophages, along with lymphoid natural killer cells, are able to kill virus-infected cells once they are activated by interferon.