Cracking the Immune System’s “Source Code”: Why Is B-Cell Technology the Ultimate Path to Antibody Discovery?-Special topic on antibody modification-Tekbiotech-Yeast and Phage Display CRO, Expert in Nano-body and Antibody Drug Development

Cracking the Immune System’s “Source Code”: Why Is B-Cell Technology the Ultimate Path to Antibody Discovery?

Why do some antibodies that perform exceptionally well in animal models fail in the human body—or even trigger a strong immune response? Ultimately, it is because the antibodies are foreign substances. One of the core functions of the immune system is to recognize exogenous pathogens or antigens and produce specific defense molecules. B cells are the only immune cells responsible for synthesizing and assembling functional antibodies in this process; this characteristic inherently makes them the “natural reservoir” for antibody screening. For now, let’s set aside the technical details and return to the basics.

First, we need to understand what B cells are. They are not ordinary cells; rather, they are the “commanders” of the immune system.

The skin and mucous membranes form the body’s first line of defense. While they react quickly, they lack specificity and cannot precisely eliminate specific pathogens. The second line of defense is also non-specific, consisting of phagocytes and antimicrobial substances in body fluids. The key lies in the adaptive immunity of the third line of defense, with T cells and B cells at its core.

In the bone marrow, B cells “shuffle the genetic deck” (V, D, and J gene segments) to generate an initial repertoire of billions of different receptors, endowing them with innate diversity. When the body encounters an antigen, the immune system initiates a “humoral immune response”—naive B cells are activated by antigen stimulation and in coordination with helper T cells, and undergo “somatic hypermutation” (only B cells expressing antibodies with higher affinity receive a survival signal, while the rest are eliminated) and “class switching” (producing different antibody subtypes such as IgG and IgA), ultimately differentiating into plasma cells capable of continuous antibody production and rapidly responding memory B cells. This is why Super SingleB? is able to obtain antibodies by isolating B cells from recovered patients or immunized individuals.

The core requirement of Super SingleB? is to identify molecules that can precisely bind to the target antigen. B cells are inherently capable of “antigen-specific recognition” within the immune system; each B cell’s surface bears a unique BCR (essentially a “membrane-bound form of an antibody”), and a single BCR can recognize only one specific antigenic epitope. When an antigen enters the body, only B cells whose BCRs can bind to that antigen are activated and proliferate by the immune system—this is equivalent to the immune system having already completed a “preliminary screening,” retaining only those B cells “capable of recognizing the target antigen.” Single B-cell technology leverages this immune characteristic by labeling antigens to create probes and screening for antigen-specific B cells.

Antibodies obtained through phage display technology “may not be as stable as those naturally selected in vivo,” and mouse-derived antibodies produced via hybridoma technology require complex humanization modifications. However, the “immunological maturation process” that B cells undergo within the immune system effectively addresses these technical challenges and ensures high-quality antibodies: within the immune system, the heavy and light chains of a B cell’s antibody are naturally assembled and paired during B cell development and undergo “affinity maturation” through the immune response; Antibodies produced by B cells undergo “correct protein folding” and “post-translational modifications” (such as glycosylation). When antibody genes obtained via Super SingleB? are transferred into a mammalian expression system, they can mimic the modification processes of the human immune system to produce functional, complete antibodies.

This explains why leading pharmaceutical companies choose to base their antibody research on B cells—the answer lies entirely within the human immune system.

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Figure 1: Differentiation of B Cells

TechBio (Tianjin) Co., Ltd. has established a comprehensive single B-cell antibody discovery platform dedicated to providing high-quality single B-cell antibody development services to scientists worldwide. This platform enables the efficient and rapid generation of fully human antibodies. We offer a one-stop service solution to provide robust support for our clients’ research projects and the development of next-generation therapeutic antibodies targeting intractable diseases.

References

[1] Kometani K,Kurosaki T. Differentiation and maintenance of long-lived plasma cells. Curr Opin Immunol. 2015;33:64-9.

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