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Fleet expertise

Proof-of-Concept & Feasibility Immunoassays

More than one assay architecture can potentially be employed to achieve any given diagnostic aim. So at the proof-of-concept stage – as well as assessing different antibody combinations – multiple assay formats may be compared to identify the most promising options.


The anticipated output from this stage of development – typically confirmed by a design review – is a single prototype assay design. 

Generally this design will then undergo further optimisation, but sometimes it is adequate per se for the required purpose – for example allowing the value of a new biomarker to be realistically assessed in clinical collaborations.

Western blot
Alzheimer's disease
ELISA plate

Example Projects

Infection marker for cystic fibrosis

To develop a novel ELISA for a bacterial toxin implicated in cystic fibrosis, Fleet managed the generation of a number of novel polyclonal and monoclonal antibodies. These were evaluated alongside commercially-available alternatives in an assay feasibility program, from which a combination of two in-house polyclonals in an immunometric format was shown to be effective at achieving the required assay sensitivity. 

An important factor in this choice of critical reagents was its economic viability; some commercial antibodies gave equivalent performance but were prohibitively expensive. The resulting assay was used in a successful clinical study to detect exacerbations of bacterial infections in CF patients.

Redevelopment of Alzheimer's assay

A UK client had identified a potential marker and therapeutic for Alzheimer's. Whilst a prototype immunoassay had been developed, this assay was problematic to run at desired throughput, and subject to considerable non-specific binding and matrix effects. Fleet was able to quickly redevelop the assay to address these issues, allowing the client to proceed with their research.

Feasibility demonstrated for novel veterinary immunoassay

Fleet's experts designed and developed an ELISA for measurement of a fungal contaminant of equine feed, which is believed to be associated with laminitis. The resulting assay was compatible with pasture samples, allowing researchers to investigate their hypothesised mechanism.

Point of care proof of concept

A UK client approached Fleet regarding development of a point of care assay for an anaesthetic agent. No suitable antibodies were available commercially, so Fleet carried out immunogen design and manufacture, liaising with the third party carrying out the immunisations to ensure that the resulting antisera met the project aims for cross-reactivity. Fleet went on to develop a proof of concept assay using the antisera that showed the required promise, such that the client was able to approach investors and research bodies for the funding of further development.

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