SYnAbs

Gosselies, 
Belgium
http://www.synabs.be
  • Booth: 2040

Booth Profile

SYnAbs' vision is to fill the gap in the marketplace for innovative antibodies against poor immunogenic compounds and complex antigens. Targeting lipids, peptides, neo-epitopes, toxins, epigenetic modifications and polysaccharides, SYnAbs has developed a strong expertise in immunology to break immunotolerance in rat and guinea pig species to generate unique monoclonal antibodies of extreme specificity and higher affinity.


 Press Releases

  • Hemoglobinopathia are diseases associated with a genetic abnormality of hemoglobin, blood protein used to transport oxygen. Hemoglobin is found basically inside red blood cells (erythrocytes), which gives them their red color.

    Human hemoglobin consists of four identical chains :

    -       two α chains

    -       two β chains

    Each of these channels is associated with a prosthetic grouping called heme. The name of hemoglobin comes from two words: heme and globin, symbolized by "Hb".

    The alpha and beta genes of globin are coded respectively on the chromosomes 16 and 11. But like many proteins, chains hemoglobin present various mutations that have the most often no impact clinical. These diseases are autosomal recessive Mendelian transmission, meaning that the disease appears only in children whose both parents are carriers of the anomaly, it is the homozygous form. In the heterozygous form (only one affected parent), the disease is most often silent, remaining transmissible.

    More than 500 hemoglobins abnormal have been listed and they fall into two broad categories.

    1. Sickle cell disease

    Also called hemoglobinosis S, sicklemia or cell anemia falciformes, Sickle cell disease is a hereditary disease, autosomal recessive, which is characterized by an alteration of hemoglobin. The red blood cells of homozygous individuals, HbS / S, do not practically only contain HbS. These molecules have the property of polymerizing when deoxygenated, giving rise to training of fibers that deform the globule and give it an appearance in sickle.

    More than 50 million people worldwide are affected by the Sickle cell disease, and more than 250'000 children with a serious form are born each year with the genetic anomaly. Sub-Saharan Africa, Middle East, India, Brazil are the main locations of Sickle cell disease.

    • Manifestations of the disease are multiple and can be listed as
    • "Vaso-occlusive" crises, caused by the obstruction of capillaries
    • Acute pain episodes due to vaso-occlusive seizures
    • Hand-foot or dactylitis syndrome
    • Hemolytic anemia
    • Acute chest syndrome
    • Stroke, Cerebrovascular accident
    • Increased susceptibility to infections
    • Chronic complications (Heart attack, kidney, dermatological, PAH, Retinopathy, Priapism, cholelithiasis…)

    So far, there is no cure for this genetic disease, except hematopoietic stem cell transplantation. The diagnosis is currently made:

    • by examining the shape of the red cells,
    • by analyzing hemoglobin by electrophoresis
    • by genetic testing.

    Under the agreement, SYnAbs will develop pair of monoclonal antibodies against different confidential types of Sickle cells diseases, to produce sandwich ELISA assay. Thanks to its unique expertise, coupled with rat and guinea pig monoclonal antibodies technologies, SYnAbs is able to target mutations and generate immune response against very specific parts of poor immunogenic antigens. All financial terms of the deal are not disclosed.

    1. Thalassemia

    Thalassemia are hereditary diseases, autosomal recessive are characterized by a

    lack of production hemoglobin :

    • Beta-thalassemia
    • Alpha-thalassemia

    Beta-thalassemia affects mainly people from Mediterranean region, the Middle East, Asia (China, India, Vietnam, Thailand) and Black Africa. It reaches as many women than men. Around 200.000 people suffer from beta-thalassemia worldwide. Adult hemoglobinopathy testing market is growing by 3,9% (CAGR) and thalassemia market is estimated to reach 3,53$ billion by 2022.

    According to the fact that the production of beta chains of globin is absent

    or only reduced, we distinguish:

    • ß-thalassemia major (Cooley anemia)
    • Intermediate ß-thalassemia
    • ß-thalassemia minor

    ß -thalassemia major

    The first signs of ß-thalassemia major appear only after the age of 6 months because the newborn's blood still contains a lot of fetal hemoglobin HbF (alpha2 / gamma2), under a often very heterogeneous form according to individuals:

    • Severe hemolytic anemia
    • Fewer
    • Irritability
    • Hepatomegaly
    • Splenomegaly
    • Ictery
    • Developmental delay

    To compensate for massive hemolysis, erythropoiesis is increased in bones leading to bone deformities. In the child the facial bones get thicker (deformation of the jaws,

    flattening of the root of the nose, excessive spacing of the eyes).

    Secondary complications due to iron overload following hemolysis / continuous transfusion may appear :

    • Endocrine and metabolic abnormalities
    • Hypogonadism 40-55%
    • Growth retardation 33%
    • Diabetes 6-13%
    • Hypothyroidism 10%
    • Heart complications
    • Cardiac insufficiency (hemosiderosis)
    • Arrhythmias
    • Cholelithiasis 

    The diagnosis is currently performed :

    • Clinical suspicion (signs, symptoms, origin ...)
    • Blood smear (hypochromic anemia, microcytic)
    • Biochemistry: Hemolysis (free biliary, LDH, Haptoglobin)
    • Serum iron, ferritin
    • Electrophoresis of hemoglobin (HbA2 3.5-8% HbF 1-2%) 

    Treatments are composed of :

    o Blood transfusion

    o Folic acid

    o Iron Chelator

    Intermediate ß-thalassemia

    In intermediate beta-thalassemia, both beta genes are altered, but they still allow the manufacture hemoglobin in a reduced amount. The symptoms are therefore much less important than in Cooley anemia :

    o Hypochromic microcytic anemia

    o Bone abnormalities (+/-)

    o No stunting

    ß -thalassemia minor

    Beta-thalassemia minor is due to mutation of only one of the two beta genes.

    Generally, this form does not have consequence on health, since the other gene is able to compensate for the anomaly and make enough beta chains for produce a normal hemoglobin level or close to normal.

    α-thalassemia

    Alpha-thalassemia is very common. It mainly affects populations from Asia (Cambodia, Laos, Burma, Thailand in particular), in its intermediate or serious forms, from Africa equatorial, and the Mediterranean basin in its minor forms. Alpha-thalassemias occurs on chromosome 16, 2 genes, encode for the alpha strings of the globin.

    The diagnosis is currently performed by:

    -       Blood smear

    -       Electrophoresis of hemoglobin

    Under the agreeement, SYnAbs will develop monoclonal antibodies against different and confidential types of thalassemia, under the forms of pairs to produce sandwich ELISA assay. Thanks to its unique expertise, coupled with rat and guinea pig monoclonal antibodies technologies, SYnAbs is able to target mutations and generate immune response against very specific parts of poor immunogenic antigens. All financial terms of the deal are not disclosed.

    About Zentech : ZenTech is a Belgian biotechnology company specialized in the development, production and marketing of IVD solutions dedicated to diseases occuring at an early stage of life. ZenTech headquarters are located in LIEGE Science Park, Belgium. ZenTech is a biotechnology company highly specialized in the diagnostic of pathologies occurring in the early life stages, from birth to adolescence (newborn, toddler and child) and in the diagnostic of chronic diseases affecting both children and adults.

  • Introduction

    Monoclonal antibodies represent therapeutics of great conditions such as cancer, inflammatory disease, organ transplantation, cardiovascular disease, infection, respiratory disease and even ophthalmologic disease.

    Monoclonal antibodies have also been widely used in biological research and in-vitro diagnosis (IVD) for over 40 years. Köhler and Milstein1 were the first to generate a monoclonal antibody in mice in 1975 using the hybridoma technique when they fused single B-cells from the spleen of a mouse to myeloma (cancer) cell line.

    The main feature of monoclonal antibodies is their monospecificity. They bind to a single epitope of their target as they are produced by a single B-lymphocyte clone. This method of producing monoclonal antibodies is still the standard. However, in recent years, alternative methods of molecular biology linked with recombinant technologies have appeared and new recombinant versions of the antibody can be validated for specificity to the target. This engineering approach has the big advantage of avoiding the loss of precious clones that do not have reliable stability. Diaclone has over 30 years of expertise in monoclonal antibody development by hybridoma technique and has a team of molecular biologists dedicated to antibody rescue and genetic engineering as well as phage display technology. To secure some high valued antibodies obtained by the hybridoma technique and to avoid troubles like hybridoma instability, molecular biology is very useful in the optimization of the coding sequence and in the reformatting of some promising antibodies

    At the end of the engineering process, the recombinant antibody needs to be tested against the target for validation. The XelPleXTM system from HORIBA Scientific is a perfect tool for this validation step. This technology belongs to a new generation of label-free interaction analysis platforms and is capable of accurate affinity determination in a multiplex mode.

    A monoclonal antibody developed at SYnabs SA (Belgium) by a new hybridoma technology for Guinea pig monoclonal antibody has been rescued and produced by Diaclone. That monoclonal antibody was highly specific to a steroid hormone (undisclosed) of 290 Da molecular weight and was analyzed using the XelPleXTM system.

    The affinity of the hormone / antibody model, as well as the limit of detection of the hormone, was determined. Thanks to the array-based format of the SPRi sensor chips, it is easy to extend these results to multiple interactions and to quickly integrate the XelPleXTM system into the validation of rescued recombinant monoclonal antibodies from Diaclone.

    As seen in Figure 1, the 3rst steps of the Mab development process are immunization, followed by cell fusion, and then cell cloning to obtain monoclonal clones by limited dilution. The rescue step begins by performing molecular biology experimentations: cell pellets from a hybridoma Mab candidate is used to obtain Heavy (VH) and Light (VL) nucleotide sequences.

    The VL and VH sequences are then sub-cloned in expression vectors which are used for transient transfection in mammalian cells to produce the recombinant antibody. After 14 days of production, the antibody is puri ed by af nity chromatography.

    Among recombinant monoclonal antibodies rescued by Diaclone according to the process described above, one well-characterized antibody binds speci cally to a 290 Daltons steroid hormone. Thanks to the XelPleXTM system (based on SPRi technology), this was evaluated.

    As seen in Figure 1, the 3rst steps of the Mab development process are immunization, followed by cell fusion, and then cell cloning to obtain monoclonal clones by limited dilution. The rescue step begins by performing molecular biology experimentations: cell pellets from a hybridoma Mab candidate is used to obtain Heavy (VH) and Light (VL) nucleotide sequences.

    The VL and VH sequences are then sub-cloned in expression vectors which are used for transient transfection in mammalian cells to produce the recombinant antibody. After 14 days of production, the antibody is puri ed by af nity chromatography.

    Among recombinant monoclonal antibodies rescued by Diaclone according to the process described above, one well-characterized antibody binds speci cally to a 290 Daltons steroid hormone. Thanks to the XelPleXTM system (based on SPRi technology), this was evaluated.

    Binding study between a 290 Daltons hormone and a speci c recombinant antibody by Surface Plasmon Resonance imaging (SPRi) technology

    Materials and methods


    Antibodies immobilization using SPRi-CFM on a SPRi-BiochipTM CMD-200MD

    The SPRi-BiochipTM CMD-200MD is a hydrogel made of carboxymethyl dextran. The SPRi-BiochipTM CMD-200MD is characterized by a thickness of 200 nm and a medium

    density. It is activated using an EDC/NHS solution in preparation for amine coupling.
Prior to the immobilization process, the antibody of interest was prepared at a concentration of 0.7 μM in 10 mM sodium acetate at pH4.0 and at pH5.0. These antibody preparations were used to immobilize the antibody on the SPRi- BiochipTM-activated surface using the SPRi-Continuous Flow Microspotter (SPRi-CFM).

    The SPRi-CFM uses continuous ow deposition to immobilize up to 48 molecules in a single printing run. Three printing runs can be performed on a single biochip (and up to 144 spots per chip can be generated). The micro uidic immobilization improves the spot homogeneity and gives a higher immobilization level. For this experiment, the ow rate oftheSPRi-CFMwassetto15μL/minandthecontacttime to 30 minutes.

    Two reference antibodies were also immobilized:
- a Diaclone negative control antibody which was prepared at the same concentration of 0.7 μM in 10 mM sodium acetate buffer at pH5.0 only, for

    referencing purposes;
- and an HFR positive control antibody which was

    prepared at 0.7 μM in 10 mM sodium acetate at pH4.0, to check for chip reactivity.

    Each antibody was immobilized in triplicates (Figure 2).

    After the immobilization procedure, the SPRi-BiochipTM was blocked using 1 M ethanolamine.

    Antibodies immobilization using SPRi-Arrayer™ on a SPRi-Biochip™ CH-LD

     The SPRi-Biochip™ CH-LD is made of a self-assembled monolayer of polyoxyde ethylene glycol. A low density (LD) of reactive polyoxyde ethylene glycol is mixed together with non-reactive polyoxide ethylene glycol. The SPRi-Biochip™ CH-LD was activated using an EDC/sulfo-NHS solution in preparation for amine coupling. The antibody of interest and a negative control antibody (prepared in 10  mM sodium acetate at pH  5.0) were immobilized in replicates on the SPRi-Biochip™-activated surface at a concentration of 7 µM using the SPRi-Arrayer™ (Figure 3). The SPRi-Arrayer™ is an automatic and compact system used in the HORIBA Scientific SPRi platform for immobilizing ligands in a multiplex format onto a SPRi-Biochip™ or a SPRislide™. This versatile instrument uses direct contact spotting and is suitable for printing on bare or 2D-functionalized SPRiBiochips™ or SPRi-Slides™. Contact spotting allows for fast and flexible microarray printings. The diameter of the printing pin can be adapted to the number of required spots in the matrix. Here, the diameter of the printing pin was 500 µm. After the immobilization procedure, the SPRi-Biochip™ was blocked using 1 M ethanolamine.

    SPRi experimental details

    The printed SPRi-Biochip™ was loaded into the XelPleXTM system. The interactions were monitored using EzSuite software. The running buffer was 10 mM PBS pH 7.4 and the working temperature was set to 25°C. Then, 200 µL of the hormone were injected into the fluidic system at a flow rate of 50  µL/min. The hormone was injected at six increasing concentrations, following a threefold dilution series: 0.5, 1.5, 4.6, 14, 41 and 125  nM. A regeneration cycle was performed between each hormone injection by flowing a 0.1 M glycine-HCl pH2.0 solution with a contact time of 30 seconds.

    Results and discussion

    Optimization of the immobilization buffer pH for the antibody of interest

    The antibody of interest was immobilized using two different immobilization buffers on a single biochip in order to evaluate and select the best immobilization buffer. The large working area of the SPRi-Biochip™ and the multiplexing capabilities of SPRi systems allow for the immobilization of different molecules and/or testing of different immobilization conditions on a single biochip. Figure 4 compares the averaged and reference-subtracted kinetic curves obtained for the antibody of interest immobilized using 10 mM sodium acetate buffer at pH 4.0 and at pH 5.0.

    Specific binding monitoring was observed for the antibody of interest while injecting the hormone at different concentrations for the two immobilization buffer pH levels. Specific hormone binding responses retained on the spots of the antibody of interest are represented in Figure 5. For each injected concentration, the specific binding responses were measured during the dissociation phase of hormone injections at the same time point. Values are reference-subtracted and spot-averaged.

    Validation of Antibody Specificity

    The unique binding of a monoclonal antibody characterizes its specificity. Figure 6 compares averaged and referencesubtracted kinetic curves obtained for the antibody of interest immobilized using 10  mM sodium acetate buffer at pH5.0 after the injections of the hormone and a structural analogue. Both molecules were injected at the same concentrations following a three-fold dilution series (from 125 to 0.5 nM).

    For the highest concentrations of the hormone, binding responses obtained were higher for the immobilization buffer at pH5.0 than for the immobilization buffer at pH4.0. According to the data analysis, we can conclude that:

    ü  The optimal immobilization buffer pH for the antibody of interest is pH5.0.

    ü  The limit of detection of the hormone is 1.5 nM (~ 0.45 ng/mL).

    ü  The saturation level is reached at 14 nM (same signal observed for higher concentrations).

    A regeneration step was performed between each molecule injection using 0.1  M glycine-HCl pH2.0 solution with a contact time of 30 seconds. Specific binding responses were observed for the antibody of interest while injecting the hormone at different concentrations, whereas no binding response was observed while injecting the analogue at the same concentrations. From this, it can be concluded that the antibody of interest is specific to the 290 Daltons steroid hormone.

    Kinetic analysis of the antibody / hormone interactions The kinetic curves were analyzed using the EzFit software. This software is suitable for processing multiplexed data intuitively. The SPRi signal obtained on reference spots (i.e. Diaclone negative control antibody) were used for referencing. Then, the data was fitted locally (i.e. Rmax (maximum of reflectivity) different for each curve) using a 1:1 interaction model (see Figure 7; orange curves correspond to the 1:1 model fits). The kinetics curves obtained showed a more linear binding profile rather than an exponential one as used in the standard fitting model. This corresponds to mass transport limited kinetics. Directly after the analyte injection starts, the binding of the analyte to the ligand is faster than diffusion, creating a shortage of analyte at the surface. This mass transport limitation was integrated in the fitting model by the addition of a km constant in the results table of Figure 7. To avoid mass transport effect, the ligand density can be reduced, or the flow rate can be increased. The affinity between the antibody and the hormone is estimated around 0.2 nM and has a high affinity interaction model. This model was also tested by using a contact spotting system to immobilize the antibody of interest on a CHLD surface chemistry to evaluate the performance of this combination “SPRi-Arrayer™ / 2D chemistry”

    Antibodies immobilization comparison between flow printing on 3D chemistry and contact spotting on 2D surface chemistry

    Figure 8 compares averaged and reference-subtracted kinetic curves obtained for the antibody of interest immobilized using the SPRi-CFM on a SPRi-BiochipTM CMD-200MD and the SPRi-ArrayerTM on a SPRi-BiochipTM CH-LD.

    Specific binding monitoring was observed for the antibody of interest while injecting the hormone at different concentrations for the two immobilization methods. Specific hormone binding responses retained on the spots of the antibody of interest are represented in Figure 9. For each injected concentration, the specific binding responses were measured during the dissociation phase of hormone injections at the same time point. Values are reference subtracted and spot-averaged. Binding responses obtained were about 3 times higher for the flow printing on 3D chemistry than for the contact spotting on 2D surface chemistry for the 3 highest concentrations of the hormone injected. However, using contact spotting and 2D surface chemistry, the limit of detection of the hormone is 1.5 nM (~ 0.45 ng/mL). The saturation level in the case of the contact spotting on 2D surface chemistry is reached at 4.6  nM. These results are correlated with the features of 3D chemistry since a hydrogel consists of a network of reactive groups, increasing the immobilization amount capacity and consequently the binding amount capacity without any steric hindrance issue. The kinetic curves obtained in the case of contact spotting on 2D surface chemistry were analyzed using the EzFit software. The curves profile was linear, similar to the flow printing on 3D chemistry. However, a successful fit wasn’t possible by integrating the mass transport limitation option. This is probably because of the low binding responses obtained in these conditions.

    Conclusion

    A recombinant monoclonal antibody rescued by Diaclone using molecular biology was evaluated using the new labelfree interaction analysis platform from HORIBA Scientific, the XelPleXTM system. This antibody binds specifically to a 290 Daltons steroid, a low molecular weight molecule. The limit of detection of the hormone was determined to be ~ 1.5 nM (~ 0.45 ng/mL). This limit of detection was obtained with a flow printing of the antibody on 3D chemistry as well as with a contact spotting technique on 2D surface. A low molecular weight molecule is very challenging to analyze with “contact spotting / 2D surface chemistry”, but the antibody of interest specific to the hormone showed that the detection of a 290 Daltons molecule is possible with this combination. This confirms that the produced antibody is of high quality. The specificity of the antibody was also verified by flowing an analogue hormone at the same concentrations. No binding response was observed with the antibody of interest while injecting the analogue hormone in the XelPleXTM system. The kinetic curves profile showed mass transport limited kinetics. An affinity of 0.2  nM for the hormone / antibody interaction was calculated with this mass transport effect taken into account in the EzFit software by the addition of a km constant. The XelPleXTM system performed well and it allowed for a complete analysis of the antibody of interest. Thanks to the array-based format of the SPRi sensor chips, the XelPleXTM system can easily extend its performance to multiple interactions and quickly integrate into biomolecule production processes such as Diaclone’s monoclonal antibodies production process at the validation step.

  • 1.    A virus 100% fatal in humans who are not vaccinated

    8.6 billion USD annual global burden.

    1 death every 10 minute in the world.

    59,000 annual deaths.

    40% of the victims are children under 15.

    This is just a few figures about rabies virus, an entity 100% fatal.

    Rabies is probably one of the oldest known virus, already depicted before 2300 BC in many ancient texts from Mesopotamia, Egypt, Persia and Palestine. Greek litterature fervently describes virus transmittion through the saliva of infected animals, like dogs, bats, cats, rabbits and horses.

    Rabies is a fatal form of encephalomyelitis caused by viruses of the Lyssavirus genus of the Rhabdoviridae family. The rabies virus is in the form of a bullet which measures on average 180 nm long and 75 nm in diameter. The genetic information is stored in a single strand of linear RNA. This RNA of about 12,000 nucleotides encodes five proteins: the nucleoprotein (N); the matrix protein (M); the glycoprotein (G), which represents the major antigen target of the protective immune response, phosphoprotein (P) and virion transcriptase (L), mainly devoted to the transcription and replication.

    2.    Any cure against Rabies virus ?

    In 1885, two French doctors found a solution. Pasteur and Roux produced the first vaccine for rabies by growing the virus in rabbits, and then weakening it by drying the affected nerve tissue.

    Typically, vaccines are administered before exposure to an infectious agent and are otherwise not very useful after exposure has occurred. Historically, rabies is an exception, immunization being used for both prophylatic and therapeutics purposes.

    Since Pasteur’s original work with vaccines containing nerve tissue, many adverse reactions and neurologic complications have been recognized. The solution to the problem of safety of rabies vaccines lay in the development of vaccines prepared from rabies virus grown in tissue culture free of neuronal tissue.

    Today, 42 worlwide manufacturers are producing 90 million vials for human vaccines (more than 15 million people are vaccinated each year), and 181 million vials for dog vaccines, using different successful cell culture approaches:

    -       Vero-cell rabies vaccine in India (e.g., Bharat Biotech, Wockhardt, the Human Biologicals Institute) and China (e.g., Chengdu Biotechnology, Wuhan Institute, Liaoning Yisheng, Changsheng Life Sciences) on microcarrier beads, originally developed by Sanofi Pasteur,

    -       BHK-21 cell culture vaccine was produced by the Institute of Poliomyelitis and Virus Encephalitides (Moscow, Russia), and by several institutes in China, including the Wuhan Institute of Biological Products,

    -       Duck embryo vaccine by The Swiss Serum and Vaccine Institute (Bern, Switzerland) then transferred to Zydus Cadila Pharmaceuticals in India,

    -       MRC-5 human fibroblasts at Merck & Co., Novartis AG, Serum Institute of India, Novartis (Chiron Behring) and many others.

    The technical advances leading to the development of the vaccine included the adaptation of the strain of virus to WI-38 cells, the inactivation of cell-free virus by β-propiolactone, and the concentration of virus by ultrafiltration.

    Two potentially inexpensive technologies for rabies vaccine production are expression of the G protein in genetically modified plants and the generation of recombinant plant viruses, both of which might be administered orally to humans in the future.

    3.    Rabies vaccine testing : potency issues for release

    At the end of the manufacturing process, all modern vaccines must have a potency of at least 2.5 IU/dose, as measured by the National Institutes of Health test.

    NIH vaccine release test is based on mice immunization followed by intracerebral viral challenge : because rabies is present in nervous tissue (and not blood like many other viruses), the ideal tissue to test for rabies antigen remains brain.

    But the NIH test has a number of huge limitations :

    • the use of mice, despite the efforts to reduce animal experimentation,
    • the handling of a virulent virus,
    • its long duration (28 days),
    • the route of challenge differs from the natural infection route,
    • its high inherent variability due to in-vivo testing, poorly fitting a batch-to-batch release testing method,
    • not user-friendly, requiring many manipulations.

    4.    A new alternative method has been developed

    Rabies subunit vaccines have been developed based upon the use of the mentioned glycoprotein (G). This molecule is composed of a cytoplasmic domain, a transmembrane domain, and an ectodomain, exposed as trimers at the virus surface. The ectodomain is involved in the induction of both virus neutralizing antibody (VNAb) production and protection after pre- and postexposure vaccination.

    It is commonly recognized that the G molecule consists of two immunologically active parts, each potentially ables to induce both VNAb and T-helpers cells :

    -       the NH2-terminal half containing one important conformational and discontinuous antigenic site (aa 34 to 42 and aa 198 to 200 associated by disulfide bridges, so called « site II »)

    -       and the COOH-terminal half containing the other major conformational and continuous immune-dominant epitopes (aa 330 to 338, so called « site III »).

    The idea was to develop a specific mouse monoclonal antibody (D1-25) that specifically recognizes the native G-protein, thanks to the binding of site III.

    Subsequent ELISA test is able to discriminate native from altered G protein, providing a strong alternative to NIH test :

    • No use of animals,
    • Avoid any biosafety concern,
    • Fast method with outcomes in a few hours,
    • Robust and validated in-vitro potency test
    • User friendly with few handling and minimum clear steps.

    Additional special feature !

    As site III is a highly preserved sequence between the different rabies virus strains, the D1-25 monoclonal antibody detects a boad spectrum of rabies strains.

    You want to benefit from this breakthrough innovation ? Contact us!

    1. Limits of immunization site against poor immunogenic antigen targets

    Gold standard in immunization procedures in animal

    Intraperitoneal (IP) and intravenous (IV) injections are well-established immunization procedures for raising mouse antibodies, and are considered as gold standard. But in the particular case of poor immunogenic compounds or haptens (like peptides, polysaccharides, lipids, small molecules…), traditional strategies can fail to generate large panels of mAbs and finally get a monoclonal antibody of high affinity and great specificity.

    Footpad immunization, a new way to raise monoclonal antibodies

    SYnAbs has found the solution to handle this difficult situation. Injection into footpad and the work on popliteal ganglia breaks the immuno-tolerance and triggers an immune response that would not normally occur in the animal. The antigenic presentation by activated resident APCs at the secondary lymphoid organs doesn’t occur in the same way as in the spleen area.

    Once primed, dendritic cells migrate to the draining lymph nodes, the DC population becoming more and more complex as migration progresses. It turns out that additional dendritic cell subpopulations appear during the process - whose phenotypes are non-existent in the spleen - and which interact differently with the T and B lymphocytes during the creation of the adaptive immune response. This latter route provides stronger stimulation, and results in a higher magnitude of the immune response. This may help reveal the subdominant epitopes, but does not seem to change the epitope hierarchy.

    « So if it works so well, what is the purpose of DNA immunization ? » you should ask.

    1. Why DNA plasmid immunization is mandatory

    DNA immunization solves different issues when you face the following situations :

    • Raising antibodies against difficult to express proteins, such as disulfide-rich domains or multi-spanning membrane proteins (MPs). If the proteins are naturally expressed in a membrane associated format, such as the multi-transmembrane G-protein coupled receptors (GPCRs) and ion channels, traditional approaches have difficulty producing full-length protein immunogens by the recombinant protein method,

    • Generating monoclonal antibodies against expensive antigens, when recombinant protein is limiting, due to the price to produce or purchase,

    • Raising antibodies against intracellular proteins : one may assume that it is necessary to re-direct intracellular proteins into secretory pathways by adding a signal peptide to elicit a better antibody response. However, in a number of monoclonal antibody production studies, DNA has been successfully used as immunogen.

    • Generating mAbs triggering bacteria, virus antigens or toxins, for which bioproduction in classical expression systems is problematic and the injection potentially lethal for the animal,

    • Raising antibodies targeting conformational antigens : peptides often do not accurately mimic the native conformation of a targeted protein, and peptide immunization often leads to the unpleasant surprise of not recognizing native protein during screening step. You can choose to develop different delivery systems including whole cells, membrane fractions, or membrane-derived vesicles, which retain the protein in the native membrane environment. However, the epitope typically represents only a small fraction of the total protein and thus, a large non-specific antibody response is often observed for these formats. Consequently, extensive counter-screening using multiple different cell lines is required, significantly expanding the cost and time for antibody generation.

    1. DNA immunization thanks to Delphi Genetics -  SYnAbs licensing deal

    DNA immunization as it exists today was pioneered in the early 1990s. Its initial use as a vaccination platform generated great excitement due to the overall simplicity of using DNA plasmids to deliver immunogens. One particularly attractive feature of DNA vaccines is that immunogens are produced in vivo, giving them the ability to induce T-cell immune responses through endogenous antigen processing and presentation pathways.

    But aside this last consideration, DNA immunization present many advantages :

    • Relative simplicity of manipulation and productionno antigen is needed. Antigens are sometimes difficult to express or purify and to find in catalogs because they are toxic, insoluble or unstable. When produced in recombinant way, it can be different from the native form and therefore lead to irrelevant antibodies. You consequently save some precious time and costs. There’s also no risk to inject contaminant (results of antigen production) like co-purified proteins, protein purification tags or Host Cell Proteins.

    • More useful than traditional approaches to generating mAbs against more difficult targets, especially membrane proteins. The DNA immunization approach can circumvent these problems because full-length proteins can be expressed in vivo when they are delivered in the form of genetic immunogen.

    • Effective in generating mAbs against conformation sensitive targets. It is well known that the structural integrity of proteins is critical for the induction of functional mAbs, yet these sensitive structures tend to be lost during the in vitro protein production process, regardless of whether they are produced as recombinant proteins or are extracted directly from cells. Production of functionally active mAbs is highly dependent on the conformation of the proteins. Expressing intact immunogens in vivo by DNA immunization appears to have the best chance of inducing mAbs with the desired biological activities.

    • DNA immunization does not require the production or purification of proteins from a pathogen, which avoids any concerns related to biosafety.

    • As a simple and flexible immunogen design approach, DNA immunization offers a wide range of options to produce novel immunogen inserts. Antigen can be full length, sub-units, fragments, novel formats, fusion proteins…mAb Expert group valorizes the synergy between SYnAbs and RDBiotech companies, the tailor-made antibody generator on one hand and the molecular biology expert on the other hand.

    • One unique feature of DNA immunization is the convenience of using the same DNA vaccine constructs to express antigens and for mAb screening step. Cell-associated antigen-based screening has been widely and successfully used for mAbs targeting transmembrane proteins, viral envelope proteins and intracellular proteins. In these cases, cells expressing the immunogens are used without the need for protein purification to screen the binding activity of mAbs by either fluorescence-activated cell sorting analysis, whole cell enzyme-linked immunosorbent assay (ELISA), or immunohistochemistry (IHC) methods.

    • DNA prime-protein boost combo. One approach that presents a great advantage for the induction of high-titer and high-quality antibody responses is the heterologous prime-boost approach. In this approach, the DNA vaccine is delivered as the priming immunization, followed by a boost with protein antigens as recombinant proteins or peptides. One finding regarding DNA priming immunization is their ability to induce higher-level of antigen specific B-cell responses.

    Thanks to the licensing-out of Delphi Genetics, SYnAbs has now the capacity to offer DNA immunization to its partners. Under the terms of the agreement, Delphi Genetics will transfer its know-how and patents to SYnAbs, which will have full access to technology and portfolio.

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    About SYnAbs

    Founded in 2015, SYnAbs is a Belgium CRO that offers tailor-made solutions in monoclonal antibodies generation. SYnAbs' vision is to fill the gap in the marketplace for innovative antibodies against poor immunogenic compounds and complex antigens. Targeting lipids, peptides, neoepitopes, toxins, epigenetic modifications and polysaccharides, SYnAbs has developed a strong expertise in immunology to break immunotolerance in rat and guinea pig species to generate unique monoclonal antibodies of extreme specificity and higher affinity.. SYnAbs is part of mAb Expert group with sister companiesRDBiotechDiaclone and QVQ.

  • SYnAbs and Univercells, two neighboring companies based in Gosselies, Belgium, today announce strategic deal signature. Under the terms of the agreement, SYnAbs will develop an immuno-assay in order to measure a confidential biosimilar monoclonal antibody developed by Univercells.

    Univercells is a technology company delivering novel biomanufacturing platforms, aiming at making biologics available & affordable to all. They’ve developed the biosimilar version of a blockbuster monoclonal antibody and like to attest batch-to-batch variability and to confirm its biosimilarity compared to the original version.

    Thanks to its anti-idiotype monoclonal antibody generation expertise, SYnAbs (https://www.synabs.be/) will develop a custom ELISA. The format of the immuno-assay will be sandwich-type enzyme immunoassay ELISA in which the biosimilar binds to the antigen on the microtiter plate and a biotinylated anti-idiotype antibody recognizes the complex. 

    The recognized antigen can be produced in E.Coli expression system by RD-Biotech (https://www.rd-biotech.com/) - SYnAbs sister company, based in France – thanks to its fermentation capacities and know-how.

    SYnAbs will determine the best conditions for the antibody pair and will optimize the different features of the assay, including but not limited to, the best suited ELISA plate, coating conditions, denaturing agents, antigen and antibody concentrations, and incubation time.

    At the end of the process, Diaclone (https://www.diaclone.com/) - SYnAbs sister company, based in France - will then perfom a bioassay efficacy testing in order to check the antibody activity on cells through EC50 measurement.

    About SYnAbs

    Founded in 2015, SYnAbs is a Belgium CRO that offers tailor-made solutions in monoclonal antibodies generation. SYnAbs' vision is to fill the gap in the marketplace for innovative antibodies against poor immunogenic compounds and complex antigens. Targeting lipids, peptides, neoepitopes, toxins, epigenetic modifications and polysaccharides, SYnAbs has developed a strong expertise in immunology to break immunotolerance in rat and guinea pig species to generate unique monoclonal antibodies of extreme specificity and higher affinity.. SYnAbs is part of mAb Expert group with sister companies RDBiotech, Diaclone and QVQ.