Antibody production in B cells is a fundamental step in the body’s immune response to foreign antigens, and an important puzzle piece in a bigger picture in immunology.
The immune system is a complex and remarkable defense network that safeguards our bodies against harmful pathogens and foreign invaders. At the heart of this intricate defense system lie the B lymphocytes, small but powerful components that play a pivotal role in the production of antibodies – the frontline soldiers of immunity.
In this blog post, we will embark on an enlightening journey into the world of B cells and their extraordinary abilities to produce antibodies. From their historical discoveries to their role in recombinant antibody production, we will uncover seven captivating facts that shed light on the significance of B cells and B cell antibody production.
As part of the adaptive immune response, B cells play an important role in recognizing and responding to antigens – foreign invaders that threaten our well-being. Once activated, B cells wield B cell receptors (BCRs) to lock onto specific antigen epitopes with astonishing precision. This essential recognition process allows B cells to act as efficient antigen-presenting cells (APCs), presenting captured antigens to helper T lymphocytes and launching a coordinated immune response.
Subscribe to our Newsletter
Get all the latest updates, and learn about our advancements in antibody production.
Subscribe now
Upon successful activation, B cells transform into antibody-secreting plasma cells, churning out a diverse array of immunoglobulins (IgM, IgG, IgA, IgE) tailored to neutralize the invading pathogens. This armory of antibodies forms the cornerstone of humoral immunity, the branch of immunity that combats pathogens circulating in the body fluids. On that account, it is noteworthy that B cells are considered the only blood cells in the immune system capable of antibody production.1
Read more on: What is an antibody?
The discovery of antibody production by B cells has been marked by significant milestones that shaped our understanding of these remarkable cells. Early in the 20th century, scientists identified B cells as a distinct population of lymphocytes found in the spleen and lymph nodes. In the 1970s, the discovery of B cell receptors (BCRs) provided insights into how B cells recognize specific antigens, revealing their prowess as antigen hunters.2
The 1980s brought a revolutionary breakthrough with the development of monoclonal antibodies, allowing researchers to isolate and produce specific antibodies for therapeutic purposes. These advances opened new possibilities for targeted treatments in various diseases.3
Advancements in genomics and single-cell analysis in the 21st century have deepened our knowledge of B cells’ diversity and complexity, shedding light on their maturation, activation, and differentiation processes, along with the mechanism of antibody production resulting from B cell response. These advancements can also be used in hybridoma technology, where B cells are fused with immortal myeloma cells to produce recombinant antibodies.
Today, armed with the knowledge of B cell activation, memory B cells, class switching, somatic hypermutation and plasma cells (also known as plasmablasts), we are at the forefront of developing novel therapies and vaccines that harness the power of B cells to combat infectious diseases, autoimmunity disorders and certain cancers (e.g. based on cell-mediated cytotoxic effects).
In the intricate orchestra of the immune system, B cells emerge as the conductors of adaptive immunity, orchestrating a precise and powerful defense against invading pathogens. Central to this process is the remarkable ability of B cells to recognize antigens and trigger a coordinated immune response.
When a pathogen enters the body, specialized antigen-presenting cells (APCs), such as dendritic cells, capture and process the foreign invaders. These APCs then present fragments of the antigens on their cell surface, acting as beacons for B cells and helper T cells.
Naive B cells, in a state of readiness, patrol the lymphoid organs, seeking their specific antigen match. When a naive B cell encounters an antigen that perfectly fits its B cell receptor (BCR), an intricate activation process is set in motion.
Upon antigen recognition, the activated B cell undergoes a series of transformations . Cell proliferation is increased, giving rise to a clone of B cells that differentiate into two primary effector cell types: plasma cells and memory B cells.
The plasma cells are antibody-secreting factories, releasing a torrent of immunoglobulins tailored to neutralize the invading pathogen. These antibodies (IgM, IgG, IgA, IgE) circulate through the body, binding to the pathogens and flagging them for destruction by other immune cells, e.g. by macrophages.
Simultaneously, memory B cells are formed, poised to provide long-lasting protection against future encounters with the same pathogen. These memory cells possess a heightened ability to recognize and respond swiftly, enabling a faster and more potent immune response upon re-exposure to the pathogen.
Crucially, B cells don’t act alone. They collaborate with helper T cells, which recognize the same antigen presented by the APCs, further fueling the immune response. The interactions between B cells and helper T cells are regulated by a complex network of cytokines, ensuring a harmonious and effective immune reaction.
Human B cell development begins with hematopoietic stem cells in the bone marrow. These stem cells give rise to B cell precursors, which undergo differentiation and acquire specific cellular markers as they commit to the B cell lineage.
During maturation, immature B cells undergo genetic rearrangements to assemble their B cell receptor (BCR), a specialized protein crucial for antigen recognition. Through recombination, diverse combinations of heavy chains and light chains form, providing B cells with a vast repertoire of BCRs capable of recognizing a wide range of antigens.
Not all B cells successfully assemble a functional BCR. Non-functional B cells undergo apoptosis, maintaining the immune response’s quality.
Mature B cells exit the bone marrow and patrol the secondary lymphoid organs, waiting to encounter antigens. The microenvironment in these organs plays a critical role in supporting B cell maturation.
Humoral immunity hinges on the remarkable ability of B cells to produce antibodies, specialized proteins that combat invading pathogens. When B cells encounter antigens matching their receptors, they undergo activation, leading to the formation of plasma cells. These plasma cells act as antibody factories, churning out a diverse array of immunoglobulins, including the isotypes IgM, IgG, IgA, IgE, and IgD.
Each class of immunoglobulin serves distinct roles in our immune defenses. IgM, the first line of defense, is rapidly produced during initial infections. IgG, the most abundant, provides long-lasting protection and can even be passed from mother to child. IgA is found in bodily secretions, offering localized protection on mucosal surfaces. IgE plays a role in allergic responses and defense against parasites, while the exact function of IgD is still being explored.
Antibodies work like skilled keymakers, crafting keys (antibodies) that precisely fit the locks (antigens) of invading pathogens. Once bound to the pathogen’s surface, antibodies can mark them for destruction by other immune cells or neutralize their harmful effects.
Memory B cells are essential guardians of our immune system, providing lasting antigen-specific protection against recurring infections. Formed during the immune response, they establish immunological memory.
Upon encountering antigens, some B cells become memory B cells, ready for a swift antibody response upon re-exposure. Through affinity maturation, their B cell receptors (BCRs) fine-tune to recognize specific antigens with heightened precision.
Circulating in the body and residing in lymphoid organs, memory B cells spring into action when a familiar pathogen returns. They differentiate into antibody-secreting plasma cells, producing high-affinity antibodies that neutralize the pathogen, preventing severe illness.
Vital for vaccination’s success, memory B cells ensure a rapid and efficient response to known pathogens, safeguarding our health with long-lasting immune protection.
B cell antibody production plays a pivotal and decisive role in maintaining overall health and combating diseases. In healthy individuals, B cells produce a diverse repertoire of antibodies that target and neutralize harmful pathogens, fortifying our immune defenses. These antibodies also contribute to the formation of immunological memory, ensuring lasting protection against recurring infections.
Conversely, dysregulation of B cell antibody production can lead to serious health implications. In autoimmune diseases, B cells may mistakenly target the body’s own tissues, resulting in chronic inflammation and tissue damage. Additionally, B cells’ role in lymphomas underscores the significance of maintaining proper B cell function to prevent uncontrolled proliferation and the development of malignancies.
Along the past few chapters, we have discussed different processes regarding in vivo mechanisms of B cells, with a focus on their ability to produce antibodies. However, there are several strategies for in vitro antibody production, and not all of them are based on B cells.
When relying on B cells, though, one frequent approach is the aforementioned hybridoma technology – antibody-producing B cells are combined with immortalized myeloma cells, allowing researchers to express recombinant antibodies in vitro.
Another frequent technique in recombinant antibody production is based on CHO cells – an approach that does not directly involve live animals in recombinant antibody production, since the cell line used originates from one individual (a chinese hamster) and was cultured since then. RAb production in CHO cells brings a variety of additional advantages, such as fast turn-around times and a high quality, as well as compliance with regulatory standards.
This is also why we at evitria focus on transient recombinant antibody expression services based on CHO cells – because we are convinced that this technology is ideal to produce a variety of antibodies suited for different purposes.
Germinal centers are specialized microenvironments within secondary lymphoid organs where B cells undergo intense proliferation, affinity maturation, and class switching. These centers play a crucial role in refining the B cell response to antigens, resulting in the production of high-affinity antibodies that are more effective in neutralizing pathogens.
B cell subsets are distinct populations of B cells with varying functions and maturation stages. Two essential subsets are follicular B cells and transitional B cells. Follicular B cells reside in the follicles of lymph nodes and spleen, actively participating in the immune response. Transitional B cells represent an intermediary stage between immature B cells from the bone marrow and mature B cells in peripheral lymphoid organs.
Interleukins are signaling molecules that play a critical role in regulating B cell activation and differentiation. Interleukin signals influence B cell responses, guiding them towards specific effector functions, such as antibody production, and shaping the immune response.
The B cell antigen receptor (BCR) is a membrane-bound protein that recognizes and binds to antigens on the surface of pathogens. BCRs have two components – heavy and light chains – which form a unique binding site for specific antigens. Additionally, B cells can also interact with major histocompatibility complex (MHC) molecules on antigen-presenting cells, a process essential for B cell activation and antibody production.