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The serum bactericidal assay (SBA) and opsonophagocytic assay (OPA, also known as OPKA) are important tools used for the evaluation of novel vaccines. The end-point of these assays is enumeration of bacterial colonies cultured in appropriate culture media.
The SBA is a globally accepted method for measuring the functional activity of serum antibodies against meningococcus. The assay is used to determine whether a subject, or a population, is seropositive against invasive meningococcus.
The SBA assay is mediated by antibody and complement resulting in lysis of the bacterial cells. To date, the SBA has proved to be the best surrogate of protection for all serogroups and is referred to as the ‘gold standard’ for monitoring meningococcal vaccine efficiency.
The end point of the SBA assay is the counting of colony forming units. The bacteria are placed in serial dilutions on blood-based agar plates. The plates are then tilted at 45 degrees and the solution runs down the plate forming ‘lanes’. The plates are incubated and after the colonies have grown, they can be counted using Sorcerer Colony Counter.
The OPA is commonly used for evaluating pneumococcal vaccines (vaccine against Streptococcus pneumoniae, which causes pneumonia and other complications) and for measuring antibody function. The opsonophagocytic assay has become an important tool in assessing pneumococcal vaccine immunogenicity.
Similar to the SBA, the end point of the assay is the counting of colony forming units. Sometimes whole plate counts can be used, but the ‘lane’ approach is also popular. Often, many samples (or dilutions) can be grown together on one large plate. After incubation, these colonies can be counted by Sorcerer Colony Counter.
We have provided Sorcerer Colony Counters to many laboratories conducting serum bactericidal assays (SBA) and opsonophagocytic assays (OPA also known as OPKA) around the world. We have worked alongside the scientists and researchers to configure and optimise Sorcerer so that it can provide fast, accurate and robust data.
Find out more about Sorcerer Colony Counter.
"Innovative software solutions for genetic toxicology assays"
Perceptive Instruments help you integrate data acquisition, auditing and reporting for your genetic toxicology assays. With over 20 years' experience, we have always delivered highly effective solutions along with excellent customer service. We have a reputation for quality and operate a quality management system to IS0 9001:2008. Over 90% of our sales are made internationally; we have extensive experience in selling, shipping, installing and supporting our products to a global market.
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