Overview of Single B Cell Screening Technology

1. Development of Single B Cell Screening Technology

In 1975 Milstein first described a method to produce monoclonal antibodies by hybridoma technology, which greatly promoted the development of immunology. Monoclonal antibodies have become an important scientific research tool and therapeutic molecule, and this technology is still the main technology for the preparation of monoclonal antibodies. It plays an important role in cell biology technology. Monoclonal antibody is an important tool in the field of medicine and immunology and plays a great role in the pathogenesis, diagnosis, and treatment of pathogens. At present, the most commonly used methods of monoclonal antibody preparation are hybridoma technology and phage display technology. Hybridoma technology is the fusion of spleen cells and bone marrow cells of immune mice to form hybridoma cells that survive in vitro for a long time secrete immune proteins and then produce monoclonal antibodies targeting the same antigen binding site, which is the most classic monoclonal antibody preparation technology. This method is mature and transparent and can produce strong specific monoclonal antibodies, but the preparation time is long, the repetitive production performance is poor, the difference between antibody batches is large, and hybridoma cells very easy to appear in the culture process chromosome loss, clonal competition, hybridoma decreased ability to secrete antibodies, etc., increase the risk of antibody development. Phage display technology inserts variable region genes of antibodies into phage genes, display the expressed antibodies to the surface of the phage, constructs a phage display antibody library, simulates the production of antibodies in vitro, and screens out antibodies against different antigens. The phage display method does not need to immunize animals, shortens the antibody preparation cycle, and has a large screening capacity, which can screen hundreds of millions of clones in a short time. However, the random combination of antibody variable region genes will lead to the loss of natural pairing of antibody heavy chain and light chain, and the modification of antibody is different from that of mammals, so the application of this method in production is limited.

In recent years, the single B cell antibody screening technology has been gradually developed, and then it has been applied to the preparation of monoclonal antibodies. This technology uses flow cell sorting to fluorescently label specific antigens and uses the principle that antigens can specifically bind to the BCR on the surface of B cells to screen out single target B cells. Then, the heavy chain and light chain genes of antibodies are obtained by PCR amplification, and the antibody genes are constructed on the expression vector. Transfected into eukaryotic cells to express monoclonal antibodies(Figure 1). Different from traditional hybridoma cell sorting technology, single-cell screening technology can directly isolate, culture, analyze, and screen single B cells, to accurately and efficiently screen out B cells secreting target antibody molecules, and then obtain the target antibody sequence by combining single-cell sequencing technology. This technique can quickly produce monoclonal antibodies against humans, rats, rabbits, alpacas, pigs, chickens, dogs, and other animals. The method is time-saving and efficient, retains the natural pairing of antibodies, and has been widely used in the research of infectious diseases such as HIV, COVID-19, and influenza.

Figure 1: Schematic diagram of the preparation of McAbs based on single B cell antibody technology

2. Significance of Single B Cell Screening Technology in Biotechnology Research

Monoclonal antibody plays an important role in the prevention, diagnosis, and treatment of diseases, especially in the study of immune mechanisms. With the development of monoclonal antibody preparation technology, single B cell antibody preparation technology has become a new generation of rapid monoclonal antibody preparation methods. Compared with traditional antibody preparation technology, this technology has the advantages of fast, efficient, and high yield, and the antibody expressed has a natural conformation, which can not only be used for the development of antibodies related to pathogenic microorganisms and the study of the mechanism of virus cross-species transmission but also plays an important role in anti-tumor therapy and anti-autoimmune. diseases.

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