Low-pH increases the binding of haemorrhagic septicaemia rhabdovirus to membrane phospholipids

The rhabdovirus causing viral haemorrhagic septicaemia (VHS), a disease of coldwater fish, especially salmonids, binds to sonicated radioactively labelled membrane phospholipids [phosphatidylserine (PS), phosphatidylethanolamine (PE) and phosphatidylcholine (PC)]. The extent of binding of VHSV to membrane phospholipids is dependent on pH, occurring at physiological pH, but being maximal at about pH 5.5 and suggesting that a pH-induced conformational change is needed for the VHSV to maximally bind phospholipids. VHSV bound PS more effectively than either PE or PC, as demonstrated by ultracentrifugation and competition experiments.