Scientists at Oklahoma State University in Stillwater and the University of Texas Health Science Center in San Antonio have revealed new details about how poxviruses disable the human immune system (Krumm B et al. Proc Natl Acad Sci U S A. 2008;105:20711-20715).
Orthopoxviruses, such as the virus that causes smallpox, trick the human immune system by creating their own version of human interleukin 18 binding proteins (IL-18BP). These virus proteins bind to human interleukin 18 (hIL-18), preventing the immune system from mounting an effective defense. But the precise details of how these molecules bind have been elusive. The researchers used an x-ray crystallography technique, the single-wave anomalous dispersion method, to elucidate the crystalline structure of an orthopoxvirus IL-18BP as it binds to IL-18.
Kuehn BM. Picturing Poxvirus. JAMA. 2009;301(9):924. doi:10.1001/jama.2009.244