Abstract
Over the last 10 years the structure of various human interferon-α (IFN-α) and interferon-γ (IFN-γ) subtypes was elucidated by combining protein chemistry and molecular biology. In this article some key studies related to the interferon structure are reviewed. The significance of the multiplicity of IFN-α and IFN-γ subtypes is discussed in view of some current results.