How do body cells respond when attacked by viruses?

The body has two immune response processes to combat viruses.

The first is called Innate Immunity and works within a few hours of an infection. With this reaction, inflammation occurs which is triggered by Toll-like receptors (TLR). These TLRs are pattern recognition receptors. They activate the Interferon (IFN) regulatory pathway, and in turn, the infected cell secretes IFN-beta. IFN-beta warns neighboring cells of the infection, and triggers the PAX/STAT pathway which leads to the production of antiviral agents and chemokines to increase the flow of macrophages and Natural Killer (NK) cells to the site of the infection.

After a few days, the second immune response, adaptive immunity kicks in. Here dendritic cells (antigen-presenting cells) are infected and carry the virus to the lymph organs. In the lymph organs the virus triggers the proliferation of B and T cells (lymphocytes that are each specific for a particular antigen) which produce antibodies to combat the infection.