Design and Synthesis of Compound-specific Haptens (Aring /B ring) for Steroid Hormones
Steroid hormone haptens will not be able to stimulate the animals to produce specific antibodies directly. However, they can be modified to introduce an accessible functional group as well as a connecting arm and then combined with a macromolecular carrier, such as a protein, and in turn, they can induce strong immune responses to produce anti-hapten antibodies. With years of experience in antigen design and antibody development, Creative Biolabs holds specific expertise in the design and synthesis of haptens and coupling of haptens to a best-fit carrier, as well as subsequent preparation of anti-hapten antibodies.
Why do Steroid Hormones Haptens need to Be Re-designed?
Steroid hormones are a group of small molecules characterized by three six-member rings (A, B, C) and one five-member ring (D) called a cyclopentanophenophenanthrene ring system. If containing active groups such as -COOH, -NH2, -OH, etc., the steroid hormones can be used as haptens that can be directly coupled to the carrier for the preparation of artificial antigen. However, under some conditions, the haptens must be re-designed and modified:
- There are no active groups available on the hapten;
- The active groups on the hapten can not be conjugated because they are very important to maintain the hapten immune characteristics and structural features;
- After coupling to the carrier, the hapten structure is easily affected by the local micro-chemical environment or steric resistance of the carrier.
Fig.1 Structure diagram of steroid hormones with the crucial difference in D ring.
What Should Be Considered During Hapten Design and Modification?
The basic principle of hapten design is to maintain the original molecular structure of the steroid hormones and to make the hapten to be exposed to the surface of the carrier as much as possible. To prepare a perfect immunogen, namely steroid hormones hapten-carrier complex, you should choose: an appropriate active group, optimal modification site(s) and linking spacer, best-fit carrier and conjugation ratio of the hapten and carrier molecules, suitable coupling method & conditions & rate, etc. Then, you can obtain the best steroid hormone hapten which can stimulate the animal to produce specific immune responses and generate high affinity and high specificity antibodies.
Design and Synthesis Compound-specific Haptens (Aring /B ring) for Steroid Hormones
Numerous studies have shown that the specificity spectrum of the resultant antibody is largely related to the hapten spacer site that connected with carrier proteins. Creative Biolabs deeply understand and obey the following basic principles to determine the best-fit spacer site: 1) the linking spacer should be far from the functional groups or the most distinctive groups to avoid affecting recognition of antibodies to the hapten. 2) The length of the spacer arm should be appropriate. 3) Spacer arm should not contain strong determinants such as the aromatic ring, conjugated double bonds or heterocyclic, etc.
Because most of the steroid hormones share a nearly similar structure of A and B rings, with the crucial difference in ring D. When performed hapten modification, if choosing the D ring as the linker site, the characteristic structure of different steroids is hard to be exposed on the surface of the artificial antigen, so it would be difficult for the animal immune system to identify the hapten, leading to the production of low affinity and low specificity antibody. Therefore, A and B ring modification is an accessible approach to obtain compound-specific hapten and high-specificity antibodies that can well recognize different steroid compounds.
Based on steroid hormones, we provide a one-stop service on hapten design and synthesis.
Creative Biolabs has accomplished several cases in designing & preparing haptens and developing associated small molecular antibodies with the desired specificity. For questions or a personal consultation, do not hesitate to contact us.