Beyond Recombinant Proteins: The Native Antigen Company Molecular Engineering Expertise
Most scientists know The Native Antigen Company (TNAC) for its recombinant proteins, antibodies and virus-like particles. However, the same molecular biology and protein engineering expertise that supports diagnostic and vaccine development can also be applied to a very different challenge: creating traceable microbial strains and biological materials for test and control manufacturers.
Through capabilities spanning vector design, genetic engineering, recombinant expression and custom development across bacterial, insect and mammalian systems, TNAC supports complex molecular biology projects that extend well beyond recombinant protein production.
The Challenge: Distinguishing Real Contamination from Control Carryover
False positive results remain a significant concern in food microbiology laboratories. A positive result may lead to product holds, repeat testing, delayed release and increased operational costs. In some cases, the challenge is not the test itself but determining whether a signal originates from genuine contamination or inadvertent carryover from a positive control.
As testing requirements become increasingly stringent, manufacturers are seeking ways to improve traceability and confidence throughout the testing workflow.
An Industry Challenge That Sparked Innovation
This was not simply a hypothetical problem. The challenge was brought to TNAC by a renowned manufacturer of microbiological control materials seeking an innovative way to distinguish genuine contamination events from positive control carryover. The objective was to create microbial strains that could integrate seamlessly into existing testing workflows while remaining uniquely identifiable.
Leveraging our expertise in molecular biology, genetic engineering and recombinant systems, TNAC explored approaches based on stable genomic integration of fluorescent markers, demonstrating how the same scientific capabilities used to express complex recombinant proteins through development of stable mammalian cell lines can also be applied to the next generation of microbiological controls and reference materials. The project focused on engineering GFP-expressing bacterial strains with chromosomally integrated markers designed for long-term stability and minimal impact on the behaviour of the parent organisms.
The outcome was a practical demonstration of how advanced molecular engineering can bring traceability directly into microbial controls. By incorporating a stable fluorescent marker into the bacterial genome, control manufacturers can create organisms that are instantly distinguishable from true contaminants, reducing uncertainty and increasing confidence in testing results.
Figure 1. PCR performed on parental wildtype E. coli O157, intermediate E. coli O157:pKM208 harboring the plasmid-based Lambda-Red recombinase system, and the E. coli O157:GFP with the gnomically integrated GFP expression cassette. Primers were designed to span the GFP integration site, and strain and plasmid specific primers were used to show strain specificity and absence of pKM208 plasmid in the E. coli O157:GFP
Figure 2. Propagation of parental wildtype E. coli O157, intermediate E. coli O157:pKM208 harboring the plasmid-based Lambda-Red recombinase system, and the E. coli O157:GFP with the gnomically integrated GFP expression cassette on non-selective and LB-Amp agar plates. The streak of E. coli O157:GFP shows fluorescence when illuminated by a BlueBox or UV lamp, whereas propagation on selective agar shows that the resulting E. coli O157:GFP is cured of the pKM208 plasmid.
Applying TNAC's Engineering Expertise
TNAC's molecular biology team has explored the engineering of GFP (Green Fluorescent Protein)-expressing bacterial strains, including E. coli, Salmonella, Listeria and Cronobacter reference organisms. These projects utilize genomic integration strategies designed to provide stable fluorescence while maintaining growth characteristics that closely resemble the parent strain. Key development objectives included avoiding antibiotic resistance markers and ensuring long-term construct stability through chromosomal integration rather than plasmid-based expression.
At the heart of this approach is a simple concept: build traceability directly into the organism. Rather than relying on external identifiers or unstable genetic elements, fluorescent markers can be integrated into carefully selected genomic locations, creating strains that remain genetically stable and consistently identifiable over time.
Unlike plasmid-based systems, chromosomal integration offers greater stability and consistency, helping ensure reliable signal generation across batches while maintaining characteristics that closely resemble the original reference strain.
Opportunities for Control Manufacturers
For manufacturers of microbiological controls, proficiency testing materials and assay verification products, traceable organisms offer several potential advantages:
Importantly, the underlying engineering principles are not limited to GFP or E. coli. Similar molecular approaches can be applied to a wide range of microorganisms, opening opportunities for tailored solutions across food safety, environmental testing and clinical microbiology applications, and engineering of a number of Salmonella strain is already under way.
How TNAC Can Help
While TNAC is best known for delivering recombinant antigens, antibodies and VLPs, our custom development capabilities extend far beyond protein production alone.
Our scientists routinely design expression constructs, engineer recombinant strains, develop custom cell lines, optimize expression systems and create bespoke biological materials for customers worldwide. From feasibility assessment and molecular design through to development and characterization, we help customers solve technically challenging problems using advanced molecular biology approaches.
For organizations developing microbiological controls, assay verification reagents or specialized reference materials, these capabilities provide access to the same molecular engineering expertise that underpins TNAC's recombinant protein portfolio.
What TNAC Does and Does Not Provide
As an ISO 9001-certified organization, TNAC can support the research, development and engineering of custom microbial strains and biological materials. However, we do not manufacture or supply finished microbiological control products intended for routine quality control testing.
For customers seeking commercialized controls, proficiency testing products or certified reference materials, we can recommend other specialist businesses within the LGC Group that focus specifically on these applications and offer established portfolios of control and quality assurance products.
Expanding the Possibilities of Molecular Engineering
The GFP-traceability project demonstrates how TNAC's expertise can be applied to challenges that extend beyond recombinant proteins and antibodies. By combining molecular biology, genetic engineering and custom development capabilities, we can help manufacturers explore innovative approaches to improve traceability, reduce testing uncertainty and develop the next generation of biological reference and control materials.
Whether the goal is producing a complex recombinant antigen, engineering a custom microbial strain or developing a novel biological material, TNAC provides the scientific expertise needed to transform challenging concepts into practical solutions.