The key difference between T cells and B cells is that T cells acts against the invading bacteria and virus and kills them, also kill the infected cells while B cells form plasma cells which further form antibodies which act against antigens.
Both B cells and T cells are the types of Lymphocytes which are a type of white blood cells, the major part of our immune system. Lymphocytes provide immunity to our body against infections. There are many differences between T cells and B cells. T cells directly kill the infected bacteria and virus or the infected cells while B cells form plasma cells which are further processed to form antibodies that act against the antigens.T cells are originated in the bone marrow while maturation occurs in thymus B cells are originated and matured in bone marrow in mammals and in bursa of Fabricius in birds.
T cells have specialized receptors known as TCR while B cells have their own receptors known as BCR. T cells do not have surface antigens while B cells have surface antigens.T cells constitute almost 80% of total lymphocytes in the blood while B cells constitute about 20% of total lymphocytes in the blood.There are four major types of T cells, i.e., cytotoxic or CD8 T lymphocytes, helper or CD4 lymphocytes, suppressor T lymphocytes, and memory T lymphocytes. While B cells have two major types, i.e., memory cells and plasma cells.
T cells are the part of cell-mediated immunity while B cells are the part of humoral or antibody-mediated immunity.T cells secrete the lymphokines while B cells secrete antibodies.T lymphocytes go to the infected site while B cells form plasma cells which do not move towards the infected site.
Cytotoxic T cells directly kill bacteria, virus or infected cells. Helper T cells help the cytotoxic cells in their function. Suppressor T cells suppress the immune system when all the pathogens and infected cells are removed. Memory T cells make the memory of the invading pathogens so that when the attack of the same types of pathogens occurs latterly, the immune system can respond early. When talked about B cells, B cells form the plasma cells which function is the formation of antibodies which kill the antigens released by virus, bacteria or other antigens entering the body. Memory B cells make the memory of foreign antigens so that on the next attack of similar antigens, the immune system can give the early response.
Comparison chart
| Basis | T cells | B cells |
| Definition | T cells are the type of lymphocytes which attack the invading bacteria, virus or fungus and kill them, as well as kill the infected cells. | B cells are also a type of lymphocytes which form the plasma cells that form antibodies against the foreign antigens or antigens produced by invading pathogens. |
| Origination and maturation | T cells are originated in the bone marrow while their further maturation occurs in the thymus. | B cells are originated in bone marrow while their further maturation occurs in bone marrow in mammals and in bursa of Fabricius in birds. |
| What they secrete | T cells secrete lymphokines. | B cells secrete antibodies. |
| Surface antigens | T cells have no surface antigens. They identify the viral and bacterial antigens outside their surface and attack them | B cells have their own surface antigens. |
| Movement | T cells move towards the site of infection. | B cells form plasma cells which do not move towards the infected site. |
| Type of immunity they provide | They are part of cell-mediated immunity. | They are part of humoral or antibody-mediated immunity. |
| Receptors | The receptors of T cells are called TCR. | The receptors of B cells are called BCR. |
| Part of lymphocytes | They constitute 80% of total lymphocytes. | They constitute 20% of total lymphocytes. |
| Types | T cells are further divided into four major types, i.e., cytotoxic or CD8 T cells, helper or CD4 T cells, memory T cells, and suppressor T cells. | B cells are further divided into two types, i.e., plasma cells and memory B cells. |
| Functions | Cytotoxic T cells kill the invading pathogens, i.e., bacteria, virus, and fungus. They also kill the infected cells. Helper T cells help cytotoxic T cells in their function. Suppressor T cells turn the immune response off the immune response when infection subsides. Memory T cells make the memory of invading pathogens so that the immune system may give a quick response on the next attack of similar pathogens. | B cells form plasma cells. These plasma cells secrete the antibodies. Antibodies are formed according to the foreign antigens in the body. These foreign antigens are recognized and killed by these antibodies. Invading bacteria or virus may release antigens or any other foreign substance entering the body is taken by the immune system as antigen. |
What are the T cells?
T cells are the type of lymphocytes which form the major part of our immunity. T cells were named so because they were initially discovered in the thymus. Initially, they are synthesized in bone marrow while their further maturation occurs in the thymus. They form almost 80% of total lymphocytes. T cells secrete the lymphokines which kill the viral or bacterial infected cells. Also, they activate B cells to release antibodies, and thus immune response is triggered. The life span of T cells longer depends upon the presence of infection in the body. There are many types of T cells. Cytotoxic T cells directly kill viral or bacterial infected cells. Helper T cells help in the regulation of the immune system of the body. Suppressor T cells suppress the immune response when infection is resolved. Memory T cells make the memory of invading pathogens so that the immune system may give a quick response on the next invasion of the similar pathogens.
T cells are present within the lymph nodes, but when pathogens invade, they move towards the infected site.
What are the B cells?
B cells also type of lymphocytes which form the plasma cells. Plasma cells secrete antibodies which act against foreign antigens. Antibodies may be released by pathogens, or any foreign substance in the body acts as an antigen. The lifespan of B cells is often shorter.
Key differences
- T cells are the types of lymphocytes which kill the foreign pathogens and infected cells while B cells release antibodies which act against antigens.
- T cells are matured in thymus while B cells are matured in bone marrow.
- The life span of T cells is longer than B cells.
- T cells are located inside lymph nodes while B cells are located outside lymph nodes.
Conclusion
Both T cells and B cells are types of lymphocytes. Since both play a role in the immunity of the body, so often they are confused with each other. It is mandatory to know the differences between both. In the above article, we learned the clear differences between T cells and B cells.