B cells are a type of lymphocyte that are responsible for the humoral immunity component of the adaptive immune system. These white blood cells produce antibodies, which play a key part in immunity. Each B cell contains a single round nucleus.
Lymphocytes account for about 25% of white blood cells, and B cells represent approximately 10% of total lymphocytes.
B cells both originate from and mature in the bone marrow, which is the soft fatty tissue inside bones.
B cells produce antibodies, or Y-shaped chromosomes that are created by the immune system to stop foreign substances from harming the body. B cells have B cell receptors (BCRs) on their surface, which they use to bind to a specific protein.
Once the B cells bind to this protein, called an antigen, they release antibodies that stick to the antigen and prevent it from harming the body. Then, the B cells secrete cytokines to attract other immune cells. They also present the antigens to T cells, which they recognize using their T cell receptors (TCRs). The T cells destroy the antigens.
When infectious agents, such as bacteria, enter the body, pieces of their machinery can be visible on the surface of their cells. These pieces are called antigens, and B cells activate when they encounter and recognize antigens.
B cells have B cell receptors (BCRs) on their surface, and these BCRs bind to specific antigens. Once the cell binds to the antigens, activation begins.
B cells recognize infectious agents by the shape of the antigens on their surfaces. The cells descended from a single B cell produce the same antibodies and remember the invader and antigens that led to their formation. This memory means that B cells produce the antibodies that counteracted the original antigen, protecting the immune system from a second attack.
B cell isolation is the separation of B cells from other cell populations. B cells are identified by their surface markers, CD19 and CD20.
Activated B cells become plasma cells and produce large amounts of antibodies. These activated B cells can be identified using the CD138 marker.
The same cell isolation methods used for T cell isolation can be used for B cell isolation.
There are a few different approaches to B cell isolation.
One method is selection. Positive selection is when B cells are targeted by the removal mechanism and retained for downstream analysis. On the other hand, negative selection is when other cell types are removed to leave the B cells untouched. For more information on these selection methods, read our article on Positive Selection vs. Negative Selection.
B cell depletion is another approach, where a single cell type—in this case, B cells—is removed from a biological sample.
There are two types of lymphocytes: B cells and T cells. They are both critical parts of the immune response and are interconnected, because T cells are required to activate B cells.
While both B cells and T cells are involved in triggering the immune response, the main difference between the two is that T cells can only recognize viral antigens on the outside of infected cells and B cells can only identify the surface antigens of the infectious agents themselves.
An unusually high B cell count can indicate several issues in the human body:
A low B cell count could be a sign of acute lymphoblastic leukemia or a disease that weakens the immune system, such as HIV. Additionally, lymphocytopenia (also known as lymphopenia) can be caused by a low lymphocyte count.
Yes. DNA is encased in the nucleus of cells, and B cells have nuclei.