Like an office building using a surveillance system and a man to identify and prevent unwanted visitors from entering the premises, the immune system uses an army of specialized cells and organs to identify, and prevent foreign invaders from debilitating our bodies. An indispensable part of the body’s defense system includes B and T cells which are special units of the immune system. They play a crucial role 24/7 in searching and destroying the relentless onslaught of harmful viruses, bacteria, cancer cells and toxins.
What are B-Cells (B Lymphocytes)?
B-cells are a type of white blood cell called lymphocytes. B-cells mature in the bone marrow and make proteins called antibodies, that play a vital role in protecting the body against infection, cancer and foreign substances. The antibodies target pathogens in extracellular bodily fluids, humoral immunity.
It’s an adaptive immune response, meaning a person’s defense system responds to the invasion of a specific antigen. (An antigen is any substance that causes the immune system to produce antibodies.) B-cells store the “faces” of deadly intruders in its memory bank so that the next time, for example, the same viruses invade the body, the protective antibodies snap into action to neutralize them.
Where are B-Cells Found?
The process of producing white blood cells begins before birth and continues throughout life. B-cells are located in different areas of the body. In fetuses, the liver makes B- cells. After birth, B-cells develop from blood making stem cells in the bone marrow that eventually become B-cells. Mature B-cells can be found in the spleen and lymph nodes.
What Are the Types of B-Cells
There are two types of B-cells:
- Plasma cells release antibodies in response to antigens. Antibodies are molecules the body makes to fight germs. They bind to pathogens, toxins and foreign bodies to neutralize them. Mature plasma cells can release up to two thousand antibodies per second. And they have a shorter life span compared to memory cells.
- Memory Cells remember the antigen so that the immune system can identify, locate and quickly target it in the future. Memory cells can circulate in the bloodstream for decades. Plasma cells can become memory cells.
Why Study B cells? From Science to Medicine to Patient — Immunotherapy
Scientists continue to work to get a better understanding of how B-cells function to battle diseases and improve the well-being of patients. For instance, by studying the workings of B-cells, scientists have generated monoclonal antibodies, also called mAbs. They are proteins engineered by researches in the laboratory that act like our body’s antibodies. They attack and neutralize specific substances (antigens) in the extracellular fluid to restore the body to good health using humoral immunity.
By studying B-Cells scientists created mAbs drugs to treat many diseases including several types of cancer. Some cancers that are treated with monoclonal antibodies drugs include:
- Chronic lymphocytic leukemia
- Head and neck cancer
- Colorectal cancer
- Breast cancer
How are monoclonal antibodies manufactured?
- Scientists select the target antigen (harmful foreign substance, e. g., cancer cells) against which the monoclonal antibody will be developed.
- In the laboratory researchers produce the genetically engineered desired monoclonal antibodies. The antibodies are grown in a cell culture.
- The mAbs are harvested and filtered to remove cells, debris, and purified
- The purified monoclonal antibodies are formulated into a stable liquid. The final product is filled into vials, syringes, or cartridges, and sealed.
Basic research on how B cells function has led to treatment choices for doctors in managing patients with cancer and other diseases. Monoclonal antibodies have been used to target specific cancer cells. Patients should discuss with their oncologists, cancer doctors, the success rate, side effect and cost of such treatment.
Glossary
Plasma cells are white blood cells that produce large amounts of a specific antigen. They are also called plasmacytes, and effector B cells, and can become long-lived memory cells.
Immunotherapy is the study of the immune system It works to fight diseases and foreign substances.
An effector cell is any cell that actively initiates an immune reaction in response to a stimulus and effects some change. Effector B cells are plasma cells and respond to foreign intruders by secreting antibodies. Activated T-cells carry out cell-mediated responses and include helper cells, cytotoxic cells and regulatory cells.
An antigen is any substance that triggers an immune response in the body, especially with the production of antibodies against that specific substance. The antigen is a kind of “marker,” a protein, with a unique shape found on the outside of cells that the immune system reads like a nametag. Your body recognizes your own antigens as “self” and harmful, non-body antigen intruders as “non-self.”
An adaptive immune response is the body’s ability to react to a specific antigen. It involves lymphocytes such as B and T cells.
The “T” in T-cells stands for thymus.
The “B” in B cells stands for bone marrow. The “B” has also been referred to as “bursa” which comes from the Bursa of Fabricus, a lymphoid organ in birds that was discovered in the 1960’s to be responsible for antibody production. B-cells are also called B lymphocytes.
Cytokines are chemical messengers between cells that help to coordinates and regulate immune responses. They’re called signaling proteins that play a crucial role in the regulation of inflammation in the body.
References
- Daniel H. D. et al; The 2019 Lasker Award: T cells and B cells, whose life and death are essential for function of the immune system; Cell Death Diff., Dec 2019
- Alberts B, Johnson A, Lewis J, et al. B Cells and Antibodies; Molecular Biology of the Cell. 4th edition; New York: Garland Science; 2002.
- Laleh Khodadadi et al; The Maintenance of Memory Plasma Cells; Front. Immunol., April 5, 2019
- Christel Weiss; One in Four Dies of Cancer. Questions About the Epidemiology of Malignant Tumours; Cancer Res, 2021
- Devon Carter; T cells, B cells and the Immune System; MD Anderson Center, November 10, 2021
- Cleveland Clinic; Antigen, 08/16/ 2022
- Lumen; B and T Lymphocytes; Biology for Majors 2
- Joseph R. Anticaglia, MD; Doctors Column HC Smart; A Snapshot of the Immune System, 2017
A future article will discuss T cells.
This article is intended solely as a learning experience. Please consult your physician for diagnostic and treatment options.