Grant S. Hansman, University of Heidelberg and the German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ), Germany, and colleagues have found a morphology change of norovirus virus-like particles (VLPs), which have the same surface properties as the real norovirus, when treated with citrate buffer. Citrate binds at the histo-blood group antigen binding pocket in the protruding (P) domain of the virus. It is involved in attaching to host ligands for norovirus infections.

Moreover, the researchers found that after citrate treatment the epitopes, the part of an antigen that is recognized by the immune system, on the P domain were more readily accessible to antibodies.

The researchers concluded that citrate, e.g., from a lemon, might protect against norovirus infections. They now test if it can also ease the disease if somebody is already infected.

• Treatment of norovirus particles with citrate,
  Anna D. Koromyslova, Peter A. White, Grant S. Hansman,
  Virology 2015, 485, 199–204.
  DOI: 10.1016/j.virol.2015.07.009