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Rekom Biotech

Quality

Rekom Biotech is committed to ensuring the highest level of quality in the design and manufacture of our IVD reagents.

Rekom Biotech is committed to ensuring the highest level of quality in the design and manufacture of our IVD reagents. Our products are designed, developed, manufactured, and distributed in accordance with our quality system, which is certified under the ISO 9001 and ISO 13485 standards. Our IVD reagents are manufactured following Standard Operating Procedures (SOPs) and undergo rigorous quality control in our laboratories. You can consult our system policy if you're interested.

We are authorized to work with genetically modified organisms (GMOs), under license number A/ES/19/I-22, issued by the National Biosafety Commission.

We are registered as an INNOVATIVE SME.

Quality Controls

Each batch undergoes various quality controls:

Since the precise determination of extinction coefficients is direct, ultraviolet absorption spectroscopy is preferred over chemical methods, such as the Lowry or Bradford methods. Protein concentration measurement is performed using the theoretical extinction coefficient of the recombinant protein obtained from Gill and vonHippel, 1989.

However, for proteins that do not contain Trp residues, experience shows that this may result in more than 10% error in the calculated extinction coefficient. Therefore, we measure protein concentration using the colorimetric assay based on the interaction between Coomassie Brilliant Blue and arginine and aromatic residues (Bradford method) with a maximum absorption shift from 470 nm to 595 nm (Bradford, 1976).

Reproducibility analyses are performed through SDS-PAGE, SEC, and ELISA assays. Excellent replicability of the production process.

SDS-PAGE Analysis
ELISA Analysis
SEC Analysis

Relative stability is performed with immunoassay analysis under different environmental conditions.

For recombinant proteins produced in Pichia pastoris, N-glycosylation and O-glycosylation are analyzed.

N-Glycosylation
O-Glycosylation

Western BLOT

Figure 1. Western blot analysis of the polyclonal Ab against the catalog numbers: RAG0053 (P1), RAG0051 (ChimMp1) and RAG0041 (P30).

ELISA

Figure 2. The dot plot graph illustrates the distribution of positive and negative sera by an indirect IgG ELISA with a protein coating of 0.025 μg/ml. Pre-validated sera by chemiluminescence (Abbott   Architect) with confirmatory test by immunofluorescence, were used in this analysis. The chart shows the optical density at 450/620 nm for positive (blue) and negative (grey) IgG sera.

Our in vivo monobiotinylated antigens are analyzed using a western blot assay with conjugated streptavidin (A) and several ELISA assays (B), including an indirect ELISA on streptavidin-coated microtiter plates (Figure 1B), and a capture ELISA with the biotinylated recombinant antigen used as a detector with streptavidin-HRP (Figure 2B).

(A)
Figure 1B. Binding capacity to a streptavidin-coated plate. The plate was coated with streptavidin at 2.5 µg/ml; increasing amounts of the monobiotinylated protein were attached, and the system was developed using the calibrator (2 µg/ml) and an anti-rabbit IgG labelled with HRP. As seen in this ELISA assay, the reactivity of the protein can be adjusted to a 4PL, reaching its maximum at a protein concentration on the plate of 0.1 µg/ml.
Figure 2B. Capacity to develop the assay. For this purpose, an anti-rabbit IgG was used to coat the plate (2.5 µg/ml), capturing the calibrator (2 µg/ml). Subsequently, increasing amounts of monobiotinylated protein were used in the assay, revealing the same by using peroxidised streptavidin at a dilution of 1:1000. The reactivity of the protein can be adjusted to a 4PL, reaching its maximum at a protein concentration on the plate of 0.4 µg/ml.

Upon client request or as an internal quality control for a capture ELISA format, we occasionally conjugate our antigens with peroxidase. For analysis, we perform a capture ELISA using a commercial test and an in-house assay.

1.A A capture ELISA assay was performed by using three different dilutions of the Rekom ChimCMV1 in order to develop a reference capture commercial test (CMV-IgM-eLA test PKS medac).
1.B. A capture ELISA assay titration was performed by using different dilutions of the Rekom ChimCMV1-HRP with 2.5 μg/ml of anti-human IgM.

All polyclonal antibodies are titrated against their immunogen by varying the antibody concentration against a fixed amount of immunogen on the plate. The resulting curve is then fitted to a four-parameter logistic regression, or 4PL.

Figure 1. Titration of the polyclonal Ab diluted in a twofold series against constant antigen concentration in plates, RAG0053 (P1) 1 μg/ml. A 4-parameter logistic regression (4PL) model was used to fit the sigmoidal standard curve.

Boost your laboratory with custom reagents

At Rekom Biotech, we design and manufacture high-quality, validated, and versatile IVD reagents for reliable and effective in vitro diagnostics.

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As manufacturers, we can tailor our products to your needs.

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