Purification of a chimeric virus-like particle from a complex culture medium
© Pedro and Ferreira; licensee BioMed Central Ltd. 2006
Published: 10 October 2006
Virus-like particles are promising delivery vectors for molecular therapy since they combine the major advantages of viral vectors with minimal, or even with complete depletion of the viral vectors disadvantages. A chimeric Simian – Human Immunodeficiency virus-like particle (VLP) have been constructed by fusion of Simian matrix protein (p17) and HIV-1 p6 protein which assemble as viral-like particles and when produced in HEK 293T cells are released to the culture medium . The purification of these VLPs from a complex culture medium involves an ultrafiltration/dialysis step, using a membrane which excludes proteins above 300kDa, and an anionic chromatography in which the particle is eluted at high salt concentrations.
293 cells were transfected with the vectors encoding the chimeric protein SIV p17-HIV p6. The chimeric protein has a molecular weight of about 24kDa that assemble in spherical structures of about 80 nm. Preliminary studies with analytical ultracentrifugation indicated that this spherical structure has a molecular weight above 1000 kDa. Therefore we expect particle retention in 300 kDa cut-off membranes, which were thus used as primary purification/concentration step.
Purified virus-like particles were obtained from a complex mammalian culture medium using a simple two-step purification process: a concentration/dialysis step, using an ultrafiltration membrane, and an anionic chromatography.
Financial support from Fundação para a Ciência e a Tecnologia, project number POCI/BIO/62476/2004, is acknowledged.
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This article is published under license to BioMed Central Ltd.