Aminoglycosides (AGs) Hapten Design and Synthesis
Hapten is generally described as a substance that is not immunogenic as such but can bind to specific antibodies (hapten-specific antibodies). A hapten may be made immunogenic by coupling it to a carrier (the immunogenic protein). The artificial antigen conjugate is then immunogenic not only to the carrier epitope but also to the hapten.
Aminoglycosides (AGs) are natural or semi-synthetic antibiotics produced by actinomycetes. They are among the first antibiotics to be introduced for clinical routine and several examples have been approved in humans. As a leading service provider of antibody construction, Creative Biolabs has extensive experience in developing polyclonal/monoclonal antibodies for small-molecule compounds. Particularly, haptens are a type of valuable but hard to solve targets for antibody preparation. Our scientists are skilled at offering the best solutions and excellent platforms for AG hapten design and synthesis, with the eventual goal of generating anti-hapten antibodies for global clients.
Introduction to AGs
AG antibiotics make up a large family of water-soluble, polycationic pseudo-oligosaccharides. Common to all members is the neamine core. The neamine core consists of a 2-deoxystreptamine (six-member aminocyclitol) glycosidically linked to a glucosaminopyranose. Other glycosyl substituents are attached at position 5 or 6 of the 2-deoxystreptamine moiety to form various pseudo-oligosaccharides classified as 4,5- or 4,6-aminoglycoside antibiotics. AGs are broadly divided into four subclasses based on the identity of the aminocyclitol moiety:
- no deoxystreptamine, such as streptomycin with a streptidine ring;
- a mono-substituted deoxystreptamine ring, such as apramycin;
- a 4,5-di-substituted deoxystreptamine ring, such as neomycin, ribostamycin;
- a 4,6-di-substituted deoxystreptamine ring, such as amikacin, gentamicin, tobramycin, plazomicin.
Fig.1 Structures of representative aminoglycosides. (Krause, 2016)
The core structure is modified with a number of amino and hydroxyl substitutions that directly influence the mechanisms of action and susceptibility to varieties of aminoglycoside-modifying enzymes (AMEs) correlated with each of AGs. As a class of potent, broad-spectrum antibiotics, AGs function through inhibition of protein synthesis. A key subgroup of AGs that have been used clinically as antibacterial agents, including kanamycin, tobramycin, amikacin, dibekacin, and arbekacin, represents the kanamycin group of 4,6-disubstituted 2-deoxystreptamines.
Hapten Design & Synthesis Services at Creative Biolabs
Immunoassay-based analysis for antigen-antibody interaction has several remarkable features, such as being quick, sensitive, accurate, and high throughput. Many studies indicated that if the molecular weight of certain analyte is less than 300 Da, an antibody will be difficult or even impossible to obtain. There’re a variety of small molecules with very low molecular weight, including AGs. Thus, it’s necessary to strengthen research on antigen preparation and antibody production for these molecules.
Our Design Strategies
As known, AGs are characterized by a core structure of amino sugars linked by glycosidic bonds to a dibasic aminocyclitol, which is most commonly 2-deoxystreptamine. The basic skeletal structure in AGs is stable in most environments (e.g. alkali, acid, or heating), but they will hydrolyze under strong alkali or acid conditions. At Creative Biolabs, we have launched a series of rapid, cost-effective strategies to design and synthesize high-quality haptens to AGs and other antibiotics as required. Our comprehensive hapten custom services cover a whole process from hapten design, hapten modification, to carrier selection and coupling reaction.
- Hapten design (e.g. preparation of hapten derivatives);
- Hapten modification (e.g. the choice of modified sites);
- Selection of carrier and coupling reaction (e.g. coupling methods and conditions);
- Purification of artificial antigens.
The preparation of qualified antigens is a precondition for generating a high-affinity and -sensitive antibody. As analyzed above, AGs hold many amino acids in their molecular structures and will display a greater activity at an appropriate pH. Therefore, it is desirable for antigen conjugation without complex design. For AG hapten-carrier conjugates, there’re various choices of the carrier, including bovine serum albumin (BSA), rabbit serum albumin (RSA), human serum albumin (HSA), keyhole limpet hemocyanin (KLH), rabbit and chicken gamma globulin, etc. Besides, a new carrier, glutaraldehyde (GA), can transport haptens and evoke immune responses by identifying haptens on the carrier. It’s a time-saving efficient coupling agent capable of inserting a five carbon-chain link-arm between the hapten derivative and carrier protein. Consequently, the successful preparation of GA after optimization allows antibodies better recognizing the structure of haptens.
Our Multifaceted Platforms for AG Antibiotics
AGs of streptomycin, kanamycin, and gentamicin, having a large positive charge, exist as the original rather than the metabolite in humans. The residues of AGs would produce common side effects, including ototoxicity and renal toxicity. Furthermore, AGs like amikacin or kanamycin can selectively cause cochlear and vestibular nerve injuries owing to the damages to the eighth cranial nerve. Among all the AGs, higher nephrotoxicity is observed in kanamycin, gentamicin, and florimycin. According to different types of AGs, our groups also provide hapten design platforms for specific antibiotics including but not limited to:
- Optimized strategies for hapten design and synthesis, based on the analysis of AG physicochemical properties
- Practiced technicians with more than 10 years of experience in antibody preparation and development
- Strict standards for quality controls (QCs) at the end of each phase, enabling super-low risk and reasonable costs
- One-on-one full service to protect clients’ rights and interests
AGs synergize with many other antibacterial drugs, which, in combination with the sustained increase in the emerge of multidrug-resistant bacteria and the potential to enhance the safety and efficacy through improved dosing regimens, have attracted a renewed interest in these broad-spectrum and rapidly bactericidal antibiotics. The essential step to developing an immunoassay for small molecular compounds is to synthesize artificial antigens with suitable immunogenicity. With strong capacities in antibody production, Creative Biolabs has multiple efficient strategies to design ideal AG haptens based on accurate chemical structures and offers custom development services of anti-hapten antibodies for global clients. If you’re interested in our services, please don’t hesitate to contact us.
- Krause, K.M.; et al. Aminoglycosides: an overview. Cold Spring Harb Perspect Med. 2016, 6(6): a027029.