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Neutralization Assay

(neutralizing antibody)

BioReliance provides additional assays in analytical services, including cell-based bioassays.  These assays are specifically used to measure the biological response of test material and are customized to client-specific requirements.


One of these types of cell-based assay is the neutralization assay. In this assay, neutralizing antibodies inhibit biological activity of a target, and cell viability or plaque reduction is the endpoint.


These assays can be used for:

  • Toxin Neutralization
  • Virus Neutralization
  • Detection of Anti-drug antibodies

BioReliance research professionals have performed thousands of neutralization assays for clients in Biopharma. We can provide a fast turn around time and the highest quality testing for neutralization assays.


Contact our experienced scientific staff to learn about neutralization assays that are best for your project needs – click here to talk to a scientist.


The toxin neutralization assay

Toxin neutralization assays assess the ability of antibodies within a tested sample to protect cells in culture from toxins. Cells are exposed to sample biological product (monoclonal, recombinant protein, etc), which is then serially diluted. Toxins are added, and effects are measured as follows.

Any live cells are visualized using cell staining reagents, which will be metabolized by giving a measurable color read out. Cells closer to death retain less color. Neutralizing antibody specific to the toxin found in the sample should bind and reduce the effects of the toxin on the cells.

To find the neutralization assays you need, use the search tool to the right. 


The virus neutralization assay


Neutralization of a virus is defined as the loss of infectivity through reaction of the virus with specific antibody. Virus and products containing a neutralizing antibody are mixed under appropriate conditions and then inoculated into cell culture.


The presence of unneutralized virus is detected by plaque formation. A loss of infectivity is caused by interference by the bound antibody with any of the steps leading to the release of the viral genome from the host cells including attachment, infection, or viral release.


There are two main types of neutralization:

1. Reversible neutralization - This neutralization process can be reversed by diluting the antibody-virus mixture within a short time of neutralization. The process requires the saturation of the surface of the virus with antibodies.  This is typical of antibody interference with viral attachment.

2. Stable neutralization – Antibody-virus complexes become more stable and the process cannot be reversed by dilution. The number of neutralizing antibody molecules required for stable neutralization is less than that of reversible neutralization. This is typical of antibody interference with viral release from the cell.

The neutralizing antibody is typically titrated in the neutralization assay against its homologous virus. The time and temperature for incubation varies with different viruses and with different cell types.

Contact us for a consultation on the neutralization assay that meets the needs of your project goals.