Virus-like particles

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Virus-Like Particles Based Vaccines
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Content
03.
Culture Modes
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Part 01
Types of Virus-like Particles
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Types of Virus-like Particles
Virus-like particles consist of one or more
structural proteins that, when expressed
recombinantly, have the ability to self-assemble.
Proteins can be arranged in single, double or
triple layers. The VLPs of human papilloma virus
(HPV) are formed by a single structural protein
that forms the basic capsid of the particle.
Other more complex VLPs contain several
structural proteins. For example, the VLPs of the
Reoviridae family are formed by two to four
different proteins arranged in several layers.
VLPs may have an external lipid envelope such as
HIV-1 VLPs. Influenza virus VLPs are also formed
by the protein core and hemagglutinin spikes
which are displayed on its surface. 1 Since
envelope-VLPs will contain proteins expressed on
their membranes, the choice of producer cell line
will be crucial.
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Types of Virus-like Particles
Different virus-like particles
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Part 02
Production Methods
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Production Methods
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Part 03
Culture Modes
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Culture Modes

• Batch mode the most used culture mode and has
  been used for many types of VLP, including HIV,
  Chikungunya virus, and Ebola virus. All the
  elements needed are added at the beginning of the
  culture with the advantage that the medium is
  well utilized, and the product is highly
  concentrated.
• Fed-batch mode small quantities of nutrients or
  medium are added during the culture to supply the
  cells with specific components depleted. Such
  strategies can extend the exponential growth
  phase and be used to reach high cell
  concentrations.
• Continuous cultivation mode fresh medium is
  added while the conditioned medium is extracted.
  This system presents a short turn-around time
  (reduces the cost associated with cleaning and
  filling of the bioreactor) and a small number of
  production steps. However, continuous production
  requires large amounts of medium, which is hard
  to adapted to large-scale production.
• Perfusion mode large volumes of media and
  cell-medium separation devices are needed.
  Although enhancing cellular growth and protein
  expression, the perfusion system impact
  negatively on cellular growth rate, protein
  expression and production cost.

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