T cells and B cells differ in their functions, like T cells are known to develop various immune response such as invading bacteria from body’s immune system, virus attacks, not supporting the organ transplant, etc., while B cells produce antibodies against the antigen. Despite showing variance in their working, T and B cells struggle with the same aim of destroying the invader or foreign particles which are harmful to the body.
Our body’s immune system is supported by many essential cells, among them, lymphocytes are one of them. As these are such white blood cells which are produced in bone marrow and further become specialized in two main parts which are T cells and B cells. When the body is attacked by the virus or bacteria or any parasites, suddenly the immune alarm activates and starts with the chain of reactions of cellular activity in the body’s immune system.
Other cells like macrophage, basophil, dendritic cells or neutrophils also start working for the defensive system, but when there is the demand of more sophisticated attack, there is a need of the T and B cells. In this content, we will differentiate the T and B cells, with a brief discussion on their work.
Content: T cells Vs B cells
|Basis for Comparison||T Cells||B Cells|
|Meaning||One of the types of lymphocyte, whose maturation occurs in thymus, while originating in bone marrow. They are helpful in identifying viruses and microorganisms by the antigens present on their surface.||Another type of lymphocyte, whose maturation and origination is in bone marrow only in mammals, while in birds it is in bursa of fabricus. B cells can recognize the antigen (foreign body) and produce antibodies against it.|
|Originate and mature in||T cells originate in bone marrow and mature in the thymus.||B cells originate in bone arrow and also mature there.|
|Situated in||They (mature T cells) are situated inside the lymph nodes, that is in the lymphoid sheath of spleen and cortex of the lymph nodes.||They (mature B cells) are situated outside the lymph nodes, that is in the respiratory tract, spleen, gut, germinal centers, in the medular and sub-capsular cords of the lymph nodes.|
|Receptors||They have the T-cell receptor, also known as TCR.||They have the B-cell receptor, also known as BCR.|
|Lifespan||They have the long lifespan.||They have the short lifespan.|
|Surface antigens||Do not have surface antigens.||They contain surface antigens.|
|Percentage in blood||T cells occupy 80% of the total lymphocytes present in the blood.||B cells occupy remaining 20% of the total lymphocytes present in the blood.
|Types||Cytotoxic T cells, helper T cells and suppressor T cells are the main types of T cells.||Memory cell and plasma cells are the two types of B cells.|
|Functions||1. They are involved in the cell-mediated immunity (CMI).|
2. T cells secrete lymphokines.
3. As they lack surface antigens, they identify viral antigens outside the infected cells.
4. T cells instantly move to the infected site and also have the inhibitory effect on the immune system.
5. T-cells work against the tumour cell or any transplanted organ.
6. Protect and fight against the pathogens like fungi, virus, which enters the body.
|1. They are involved in humoral-mediated immunity or antibody-mediated immunity (AMI).
2. B cells secrete antibodies.
3. B cell identifies the antigens on the surface of virus and bacteria, as they surface antigens.
4. They fight and protect the body from the bacteria and virus that enters the bloodstream.
Definition of T cells
T cells derived its name because they are mainly matured in the thymus in the neck, but originate in the bone marrow. In the thymus, T cells divide and differentiate into three broad categories which are helper T cells, regulatory T cells and cytotoxic or “killer” T cells which later become memory T cells.
The T cells after differentiation are sent to the bloodstream and get into the blood circulation or lymphatic system. These are important to the immune system as they remove the pathogens. Specifically, they act like soldiers who work all time with the target of destroying the invaders after searching them.
How T cells work
As soon as any foreign particle like bacteria or viruses attacks the body, T cells produce the chemicals which trigger the B cells for developing plasma cells and also activate the killer T cells for targeting and killing cells that have been affected by the invaders or are at the cancerous stage.
The regulatory T cells help in controlling the immune system, helper T cells also protect the immune system of the body and protect them from invaders and other foreign particles. Memory cells remain active all the time so that they quickly react to the invader if it attacks the body and its immune system another time, it works by producing numerous T cells to eliminate the invader immediately.
Definition of B cells
B cells or lymphocyte shows the humoral immunity, where they secrete antibodies in the blood and thus killing or removing the pathogens. The B cells form an antigen-antibody complex where each B cells covered in the antibody gets active by binding with an antigen in a complementary shape. This antigen-antibody complex triggers B cells to divides many times into the plasma cells.
B cells originate and mature in bone marrow. They divide and form plasma cells and memory cells, which plays a vital role while invading the pathogens.
How B cells work
B cell works in a different way than that of T cells, as they directly attack the invaders (foreign particles) by producing the proteins called as antibodies. These antibodies directly attack the invaders as they travel in the blood. So as soon as B cells come across the invaders, they trigger quickly to produce plasma cells and memory B cells.
Plasma cells are very specific to make the particular kind of antibody against any invader or antigen. The antibody is a kind of protein which attacks the invaders and act as the marker on the infected cell so that T cell readily identifies the infected cell and destroy it. So the antibody-coated invaders are easy to recognize and are quickly destroyed by the different proteins of the immune system and another essential function of the cells known as phagocytosis also works.
Phagocytes are known for their eating process, as they engulf the whole foreign or harmful substances or cells. Meanwhile, the plasma cells disappear after the immune response work is over, but again the memory B cells remain active for a long time so that the invader may not be able to attack the body and its immune system again as antibodies are already present for them to fight and eradicate them.
Key Differences Between T cells and B cells
Following points will display the essential differences between the two types of lymphocytes:
- Among the two types of lymphocyte T cells is one of the types, whose maturation occurs in thymus, but originate in bone marrow. Their role is to identify viruses and microorganisms by the antigens present on their surface. The second type of lymphocyte is B cells, whose maturation and origination is in bone marrow in mammals, while in birds it is in bursa of fabricus. These cells can recognize the antigen (foreign body) and produce antibodies against it.
- Mature T cells are situated in the lymphoid sheath of spleen and cortex of the lymph nodes, while mature B cells are situated outside the lymph nodes (in the medular and subcapsular cords of the lymph nodes), in the respiratory tract, spleen, gut, germinal centers.
- Membrane receptors of the T and B cells are T-cell receptor known as TCR and B-cell receptor known as BCR respectively. Even B cell have surface receptors, while T cells do not.
- T cells have the longer lifespan (from days to weeks) as compare to B cells, which have short life lasting for few days to the week.
- In the bloodstream, T cells occupy 80%, and B cells occupy remaining 20% of the total lymphocytes present in the blood.
- Cytotoxic T cells, helper T cells, and suppressor T cells are the main types of T cells, on the other hand, memory cell and plasma cells are the two types of B cells.
- T cells are involved in the cell-mediated immunity (CMI), secrete lymphokines, they instantly move to the infected site and also have inhibitory effect on the immune system, importantly they work against the tumor cell or any transplanted organ, and also protect and fight against the pathogens like fungi, virus, that enters the body. B cells are involved in humoral-mediated immunity or antibody-mediated immunity (AMI), secrete antibodies, they identify the antigens on the surface of virus and bacteria, as they surface antigens, even these cells fight and protect the body from the bacteria and virus that enters the bloodstream.
As discussed above, we noticed few similarities between two types, they are:
- Both T and B cells have the same site of origin, that is the bone marrow.
- Both T and B cells are the type of lymphocytes.
- Mainly both work for protecting the body’s immune system and fight against the pathogens.
- They are the part of the lymphatic system also.
- They are involved in adaptive immunity.
- Both cells are nucleated and motile also.
In this content, we discussed the most critical line of defence in the body, which play the essential role in protecting the body and its immune system from the pathogens attack. Their work is so specific that they can differentiate the self and the foreign particles. They even fight against the cancerous cell.
We also come to know about the immune system, which has importance for one’s survival. Without the presence of immune system, our body is open for the attack of the pathogens. So it becomes our priority to keep our body healthy.