Leukemia virus purification

Another application of RPC with membrane proteins is the purification of the inner core proteins and the envelope proteins of murine leukemia virus described by Henderson et al. [38]. Suspended purified virus was disrupted at pH 2.0 (TEA) by the addition of five volumes of saturated guanidine HCI. The resulting solution, which was slightly turbid, was injected. To separate this mixture of all known viral structural proteins on a /i-Bondapak phenyl column, an optimized solvent system was used (Fig. 6). A gradient of TFA in water (pH 2.0) to acetonitrile at 23°C was successively employed followed by a gradient to 1-propanol at 50°C. At 47% 1-propanol, the viral lipids were isocratically eluted. The most hydrophobic protein, pi5(E), (see also Table 1), was found in the last peak eluting from the column. Recovery of the viral proteins was nearly quantitative. 

Independent Assays for Provings Virus Removal. Retrovimses and vimses can also be present in culture fluids of mammalian cell lines (15,24). Certainly the absence of vims can be difficult to prove. Model vimses, eg, NIH Rausher leukemia vims and NZB Xenotropic vims, were spiked into fluids being purified, and their removal subsequently vaUdated when subjected to the same purification sequence as used for the product. 

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