Antibodies are proteins made by the body to fight off invaders. Antigens are foreign molecules recognized molecularly by the immune system, leading to the selective development of antibodies that bind the antigen. Antibodies are proteins produced by B lymphocytes that travel through the body’s circulatory system and bind to their respective antigens, eliminating them.
Animal immune systems’ capacity to generate antibodies with the ability to bind precisely to antigens has been exploited to develop probes for detecting molecules of interest in a wide range of research and diagnostic settings. No other technique today permits scientists to create such targeted molecular recognition tools.
Antibodies have several useful properties that make them ideal candidates for use as probes, the most notable of which is their high specificity. Antibodies, for instance, have a reasonably homogeneous and well-characterized protein structure, except the regions that govern antigen binding. That allows them to be isolated, tagged, and detected in a predictable and reproducible fashion using generic approaches.
1. Transgenic Animals
Transgenic animals are used in Antibody Production. Transgenic animals have had their DNA altered to express a new gene or combination of genes. Production of antibodies in high quantities for research and therapeutic purposes has significantly benefited from the use of transgenic animals.
Transgenic animals are created by inserting the genes that code for the desired antibody into an animal’s genome, usually a mouse, rabbit, or goat. Antibodies can be extracted from the animal’s blood or milk once the genes have been inserted into its genome. Since the animal can be bred and kept providing a constant supply of the antibody, this method is beneficial for manufacturing huge quantities of the antibody.
However, the antibodies created using transgenic animals may need to be modified before they can be used in humans. That is because animal antibodies are often created against mouse or rabbit proteins, which may not be fully compatible with the human immune system.
The use of transgenic mice for antibody production has various benefits despite this drawback. One benefit is the speed with which vast amounts of antibodies may be manufactured. Since the animal may be produced and kept indefinitely, a steady supply of the antibodies can be guaranteed. And the antibodies produced by transgenic animals are often of high quality and may be readily purified for research or therapeutic applications.
2. Bacterial Display
The method was created as an alternative to phage display to expand the size of displayed proteins beyond what was possible at the time. It shares some of the benefits of phage display, including high-transformation rates and simplicity of use. Most current fusion systems include the insertion of the foreign protein into an accessible loop in the carrier protein.
That is usually required because the host organism needs both the N- and C-terminal domains to function normally. Seeing as how to stop codons would truncate the fusion protein, this limits the size of insertions to around 100 amino acids and creates issues when displaying both natural proteins and random libraries.
Bioabsorption, bioconversion utilizing a whole-cell biocatalyst, and the generation of live vaccines are the only possible uses for microbial cell-surface display. However, it has never been employed to showcase a cDNA library. On the other hand, cell display has certain benefits over in vitro and phage-display methods.
3. Phage Display
This combinatorial technology has generated much interest because of its potential implications for the pharmaceutical industry’s future. Peptide discovery can use several other molecular display methods outside phage display, including yeast and bacterial display, ribosome display, messenger RNA display, complementation in situ hybridization, and covalent antibody display. In the phage display technique, the phage’s coat protein is modified to produce antibodies or peptides with an arbitrary sequence on the outside.
Target-ligand binding assays are then performed using the phage library. This strategy effectively identifies peptide drugs in the drug-discovery process. The phage display technique allows scientists to quickly build libraries and separate and detect protein interactions of molecular targets. In addition, this method is helpful in locating ligands for receptors, finding enzyme inhibitors, observing protein-DNA interactions, testing cDNA expression, tracing antibody epitopes, developing engineered antibodies, and creating vaccines.
Compared to more conventional screening methods, phage display is advantageous due to its high throughput screening ability of peptide and peptide variations, low cost, and flexibility.
4. Yeast Display
Using yeast surface display (YSD) has proven to be a useful platform technology for discovering antibodies. However, the conventional three-step approach for building antibody Fab libraries entails making heavy chain and light chain display plasmids in separate haploid yeast strains and then mating them.
One yeast cell carrying the plasmid encoding the target protein and adorned with hundreds of copies of the protein is the unit of selection in yeast display. DNA preparation and molecular biology can be performed in E. coli, whereas display and sorting can be accomplished with Saccharomyces cerevisiae.
Because of its versatility and efficiency, yeast surface display has been used in various fields, including biology, medicine, and biotechnology. Unlike ribosome and phage display, which require soluble protein expression and purification stages, yeast display is compatible with flow cytometric analysis, allowing for quantitative on-cell measures of protein expression level, stability, affinity, and specificity.
5. Hybridoma Technology
The majority of monoclonal antibodies are created using this technique. By fusing a B cell (which naturally produces the required antibody) with a cancer cell, a hybrid cell (hybridoma) can perpetually produce the antibody in question.
Final Thoughts
Antibodies provide vital functions in biology, chemistry, and medicine. Preformed antibodies are commonly offered in an antiserum for rapid, passive immunization against venomous snake venom or tetanus. These antibodies are isolated from the blood serum of previously infected humans or animals. To protect against a specific pathogen, vaccines prime the immune system to mount an attack on that pathogen. Antibody-making B cells are permanently sensitized after being triggered by a vaccine and are prepared to respond should the antigen re-enter the body later.
