Baculovirus Titer Assay

Proteos utilizes a robust economical plate-based flow cytometry assay for baculovirus titer determinations, allowing reproducible optimization of infection parameters in baculovirus infected insect cell cultures for protein production.

Understanding the multiplicity of infection (MOI) is an important step in the production of recombinant proteins using baculovirus mediated expression platforms.  The MOI is a measure of the number of infectious virus particles used for infection relative to the number of insect cells in the culture.  Based on our experience, an accurate MOI – which relies on an accurate titer assay – is essential for predictable infection kinetics and reproducibility during multiple production runs. 

The titer (infectious units (IU) per milliliter) of a baculovirus stock is determined by measuring the expression of gp64 (a baculovirus envelope protein) on the surface of infected insect cells eight hours post infection (hpi).  Our method measures the number of infected cells, in triplicate, over a series of nine dilutions of the baculovirus stock ranging from 1:2 to 1:100,000.  The assay is formatted for 96 well plates and requires a minimum volume of baculovirus stock.

While plaque and end-point dilution assays are laborious and add weeks to a project, our method is quick, reliable, and economical.  The assay can provide results in as little as 3-5 business days from receipt of the samples, only requires 1 mL of baculovirus stock, and is performed in triplicate so you can be confident of the results.

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