Optimization of chimeric HIV-1 virus-like particle production in a baculovirus-insect cell expression system.
A baculovirus-insect cell expression system potentially provides the means to produce prophylactic HIV-1 virus-like particle (VLP) vaccines inexpensively and in large quantities. However, the system must be optimized to maximize yields and increase process efficiency. In this study, we optimized the production of two novel, chimeric HIV-1 VLP vaccine candidates (GagRT and GagTN) in insect cells. This was done by monitoring the effects of four specific factors on VLP expression: these were insect cell line, cell density, multiplicity of infection (MOI), and infection time. The use of western blots, Gag p24 ELISA, and four-factorial ANOVA allowed the determination of the most favorable conditions for chimeric VLP production, as well as which factors affected VLP expression most significantly. Both VLP vaccine candidates favored similar optimal conditions, demonstrating higher yields of VLPs when produced in the Trichoplusia ni Pro insect cell line, at a cell density of 1 x 10(6) cells/mL, and an infection time of 96 h post infection. It was found that cell density and infection time were major influencing factors, but that MOI did not affect VLP expression significantly. This work provides a potentially valuable guideline for HIV-1 protein vaccine optimization, as well as for general optimization of a baculovirus-based expression system to produce complex recombinant proteins.
Pillay
Sirika
S
Department of Molecular and Cell Biology, University of Cape Town, PB X3, Rondebosch 7701, South Africa.
Meyers
Ann
A
Williamson
Anna-Lise
AL
Rybicki
Edward P
EP
D016915:AIDS Vaccines / Q000235:genetics / Q000378:metabolism; D000818:Animals; D016367:Baculoviridae / Q000235:genetics* / Q000502:physiology; D002460:Cell Line; D015870:Gene Expression; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D018411:Spodoptera; D014776:Virus Cultivation / Q000379:methods*; D014779:Virus Replication; D054301:gag Gene Products, Human Immunodeficiency Virus / Q000235:genetics / Q000378:metabolism
D016915:AIDS Vaccines; D011994:Recombinant Proteins; D054301:gag Gene Products, Human Immunodeficiency Virus