The use of aqueous two-phase systems to concentrate and purify bovine leukemia virus outer envelope protein gp51.
Enzootic bovine leucosis is a chronic lymphoproliferative disease of cattle. The causative agent, bovine leukemia virus (BLV), is related to the human retroviruses HTLV-I and -II. The external env-protein of BLV, a glycoprotein of 51 kDa, carries neutralizing epitopes and should be an essential component in a vaccine against the virus. Problems have been encountered with the concentration and purification of intact virions of BLV and other retroviruses. During centrifugation procedures the external env-proteins are to a great extent detached and consequently poorly recovered with the virion particles. Therefore, other methods are sought to obtain a high yield of the external glycoproteins. The use of two-phase systems based on water soluble polymers is described for the extraction of BLV-gp51 from culture medium. Several polymer systems were tested and the results showed that some were attractive for large scale application. The classical combination dextran-polyethylene glycol gave promising results; a partition coefficient of about 0.02 was obtained for the distribution of the gp51 between the top and combined inter- and bottom phases. In a single extraction step it was possible to obtain 45% of the glycoprotein in a small volume bottom phase and at the same time about 15-fold purified. That should be compared with a recovery of less than 20% with the conventional centrifugation procedures. It is concluded that extraction in phase systems based on water soluble polymers is a methodology well suited for the concentration and purification of BLV-gp51.
Hammar
L
L
Department of Veterinary Virology, Biomedical Center, Uppsala, Sweden.
Merza
M
M
Malm
K
K
Eriksson
S
S
Morein
B
B
D000818:Animals; D002460:Cell Line; D003377:Countercurrent Distribution; D003911:Dextrans; D004591:Electrophoresis, Polyacrylamide Gel; D015151:Immunoblotting; D001909:Leukemia Virus, Bovine / Q000032:analysis*; D011092:Polyethylene Glycols; D012190:Retroviridae / Q000032:analysis*; D012995:Solubility; D014759:Viral Envelope Proteins / Q000302:isolation & purification*; D014867:Water
D003911:Dextrans; D014759:Viral Envelope Proteins; D014867:Water; D011092:Polyethylene Glycols