Deliberately added hepatitis B surface antigen (HBsAg) and hepatitis B virus (HBV) could be removed by hydrophobic interaction chromatography from a concentrate of coagulation factors II, VII, IX and X. Chromatography in high concentrations of salt, preferably on octanoic acid hydrazide-Sepharose 4B, resulted in 104 -105 -fold reduction of HBsAg. The binding properties of HBsAg and HBV to the hydrophobic gels were similar and the chromatographic method seems particularly useful in removing low concentrations of virus-related material from protein solutions. The yield of protein from the coagulation factor concentrate was about 85% and the material showed the same stability and biological activities as before the chromatography.
