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Sorcerer Colony Counter in the Development of Meningitis Vaccines

The Health Protection Agency (HPA), and several other vaccine development units around the world, choose to use Sorcerer Colony Counter for conducting the Serum Bacteriocidal Assay (SBA).  The plates and colonies are illuminated using technology designed specifically for the SBA.

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Vaccines developed against a killer disease

Meningitis is a deadly disease which can kill within hours.  There are vaccines that provide excellent protection against some forms of meningitis, but not all.  Several organisms and viruses can cause meningitis.  Meningococcal meningitis is a bacterial form of meningitis: a serious infection of the meninges that affects the brain membrane. It can cause severe brain damage and is fatal in 50% of cases if untreated.

Within the Meningococcal bacteria, Neisseria meningitidis has the potential to cause large-scale epidemics. Twelve serogroups of N. meningitidis have been identified, six of which (A, B, C, W135, X and Y) have been reported to cause epidemics.

Licenced meningococcus vaccines exist against serogroups A, C, W135 and Y, however the vaccine for serogroup B (MenB) is still under development.   MenB is the cause of most bacterial cases in the UK and Ireland and research continues into developing a fully licenced vaccine.

The Health Protection Agency

The Vaccine Evaluation Unit at the HPA in Manchester, UK, is doing crucial work in the evaluation the serological responses to various bacterial and viral vaccines.  In particular, the HPA in Manchester has worked toward inter-laboratory standardisation of the serum bactericidal antibody (SBA) assay using human samples after vaccination with MenBvac (which is a potential MenB vaccine, developed from outer membrane vesicles (OMV) from the bacteria).

A vaccine for serogroup B was developed in Cuba in response to a large outbreak of meningitis B during the 1980s.  This vaccine was based around OMV technology.  Subsequent OMV vaccines were shown to be protective against serogroup B meningococci outbreaks in Norway, Brazil, and New Zealand, although there is still no global vaccine against serogroup B meningococci.

Interest in OMVs as vaccine carriers is growing as research exposes more of the molecular intricacies of vesiculation and how the vesicles can be co-opted to fight infectious bacterial agents.

The SBA method

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 an automatic colony counter.

Sorcerer: maximum productivity

The scientists at the HPA use Sorcerer every day of the week and have been instrumental in the adaption of Sorcerer Colony Counter in other meningitis vaccine research labs in Europe and Africa.

Sorcerer provides instant lane counts which are  shown on screen after each measurement and appear instantly in a Microsoft Excel workbook. The count data is saved as a Microsoft Excel file for analysis using in-house macros. It is possible to open up an Excel workbook containing sample codes, dilution factors etc. and instruct Sorcerer to carry out measurements directly.

The Sorcerer Colony Counter has been used in the HPA Vaccine Evaluation Unit since 1997 and has proved to be accurate, reliable and labour saving.

GLP regulations and standardised methods

Sorcerer Colony Counter has all the features you need to comply with GLP guidelines and linking the system to our user access management program, System Access Manager, allows complete compliance with the FDA 21 CFR part 11 rule on electronic records and electronic signatures.

Sorcerer Colony Counter is designed to conform to international GLPs and other regulatory requirements. The program includes highly detailed encoded audit trail files which automatically record all system activity including settings, measurement data and edits. All audit data can also be sent to Oracle databases for additional security.

It is also possible to activate GLP prompts for reasons such as: deleting a measurement or exiting without saving data.

The upcoming World Health Organisation (WHO) guidelines on the SBA assay guidelines will recommend the use of Sorcerer Colony Counter for the SBA assay.