doi: 10.1111/j.1365-2796.2010.02222.x To kill or be killed: how viruses interact with the cell death machinery

how viruses interact with the cell death machinery (Symposium).J InternMed2010; 267: 473–482. A virus (from the Latin virusmeaning toxin or poison) is a small infectious agent that can only replicate in-side the cells of another organism. Viruses are found wherever there is life andhave probably existed since living cells first evolved. Viruses do not have their ownmetabolism and require a host cell to make new products. The range of structural and biochemical (i.e., cytopathic) effects that viruses have on the host cell is extensive. Most viral infections eventually re-sult in the death of the host cell. The causes of death include cell lysis, alterations to the cell’s surface membrane and various modes of programmed cell death. Some viruses cause no apparent changes to the infected cell. Cells inwhich the virus is latent and inactive show few signs of infection and often func-tion normally. This causes persistent infection and the virus is often dormant for manymonths or years. Some viruses can cause cells to proliferate without causing malignancy, whereas others are established causes of cancer. Human organisms use a geneti-cally controlled cell death programme that prevents the spreading of viral infection and kills the virus. Between 19 and 21 November 2009, with sponsor-ship from the Journal of Internal Medicine, the Swedish Research Foundation and the Swedish Cancer Society hosted a conference in Stockholm entitled: ‘Tokill or tobekilled.Viral evasionstrategies and interference with cell death machinery’. Four comprehensive reviews from this conference are presented in this issueof theJournal of InternalMed-icine. These reviews include descriptions of: the modulation of host innate and adaptive immune defenses by cytomegalovirus; the impact of gamma-chain family cytokines on T cell homoeostasis in HIV-1 infection and the therapeutic implications; approaches to killing tumours by depriving them of the mechanisms for detoxification; and viral strate-gies for theevasionof immunogeniccelldeath