Interferons and natural killer cells

The interferons (IFNs) are a family of at least 16 distinct proteins and glycoproteins that exert profound biological effects in minute amounts. IFNα, IFNβ and IFNγ all have in common the ability to protect cultured cells against infection by viruses. In addition, they have a wide range of biological regulatory fuctions, including cellular proliferation, morphology, differatiation, enzyme induction, cell-surface antigen expression and function.Furthermore, the IFNs, particularly IFNγ produced by T cells are potent immunoregulatory molecules, which can affect antibody formation, antigen presentation, cell-mediated immunity and macrophage activation. Of particular interest is an immunological mechanism by which non-immunized lymphocytes, natural killer (NK) cells, can selectively lyse some tumour, embryonal and virus-infected target cells in vitro. The effector cells are non-T, non-B cells whose cytotoxic potential is regualted primilarily by IFNs. Lysis of susceptible target cells appears to be mediated by a process of vesicular degranulation and release of cytotoxic factors.With the availability of cloned IFNs, it should be possible to assess the role played by the IFN Nk cell system in preventing or restricting viral infection, and inhibiting tumour growth and metastasis.