The key difference between T lymphocytes and B lymphocytes is that the T lymphocytes originate in bone marrows and mature in the thymus while B lymphocytes originate and mature in bone marrows.
The main two types of cells in blood are red blood cells (RBC) and white blood cells (WBC). RBC carries and transports oxygen while WBC helps in defense mechanisms. There are two main types of white blood cells as granulocytes and agranulocytes. Granulocytes contain granules in the cytoplasm while agranulocytes do not have granules in the cytoplasm. Agranulocytes have two main types: lymphocytes and monocytes. Lymphocytes are similar in appearance, but they have different functions. Based on their functions, lymphocytes are divided into T lymphocytes and B lymphocytes. Both are important to fight against infections. The main aim of this article is to discuss the difference between T lymphocytes and B lymphocytes.
CONTENTS
1. Overview and Key Difference
2. What are T Lymphocytes
3. What are B Lymphocytes
4. Similarities Between T Lymphocytes and B Lymphocytes
5. Side by Side Comparison – T Lymphocytes vs B Lymphocytes in Tabular Form
6. Summary
What are T Lymphocytes?
T lymphocytes are a type of lymphocytes, and also a type of white blood cells involved in cell-mediated immunity. 80% of the lymphocytes circulating in the blood are T lymphocytes. They are agranulocytes. T lymphocytes originate in the bone marrow. Later, they migrate to thymus for maturation. Hence, the name “T cells” is given to these cells.
Figure 01: T Lymphocyte
There are three types of T lymphocytes: helper T cells, cytotoxic T cells, and suppressor T cells. Helper T cells indirectly induce the immune system by secreting cytokines. Cytotoxic T lymphocytes directly kill the infected cells by phagocytosis while suppressor T cells suppress the inappropriate immune responses in the body.
What are B Lymphocytes?
B lymphocytes or B cells are the second type of lymphocytes involved in humoral or antibody-mediated immunity. They are also agranulocytes. B lymphocytes originate and mature in bone marrow. They account for 20% of the circulating lymphocytes in the blood.
Figure 02: Function of B lymphocytes
There are two types of B lymphocytes as plasma cells and memory cells. Plasma cells activate and secrete antibodies when encountering an antigen. Secreted antibodies then neutralize the antigens. Antibodies are specific to the infection. That means; different infections will produce different antibodies.
What are the Similarities Between T Lymphocytes and B Lymphocytes?
- Both T lymphocytes and B lymphocytes are white blood cells.
- They are agranulocytes (no granules in the cytoplasm).
- Also, they are specific immune responders (the immune system can identify the invaders and attack).
- And, they are involved in adaptive immunity of our body.
- Moreover, both types circulate through the blood.
- And, both are produced by the bone marrow but mature in different places.
What is the Difference Between T Lymphocytes and B Lymphocytes?
T lymphocytes and B lymphocytes are two types of lymphocytes present in our blood. T lymphocytes involve in cell-mediated immunity while B lymphocytes involve in antibody-mediated immunity. So, this is the key difference between T lymphocytes and B lymphocytes. Furthermore, T lymphocytes produce cytokines while B lymphocytes produce antibodies. Also, a further difference between T lymphocyte and B lymphocytes is their maturation site. T lymphocytes mature in the thymus while B lymphocytes mature in the bone marrows.
Moreover, there are three types of T lymphocytes as helper t cells, cytotoxic T cells, and suppressor T cells while there are two types of B lymphocytes as plasma cells and memory cells. Besides, T lymphocytes move to the site of infection while B lymphocytes do not move. Therefore, we can consider this also as a difference between T lymphocytes and B lymphocytes. Furthermore, 80% of the circulating lymphocytes in the blood are T lymphocytes while only 20% are B lymphocytes. Hence, this is also a difference between T lymphocytes and B lymphocytes.
The below infographic presents more information on the difference between T lymphocytes and B lymphocytes comparatively.
Summary – T Lymphocytes vs B Lymphocytes
Lymphocytes are a type of white blood cells important in adaptive immunity in our body. T lymphocytes are involved in cell-mediated immunity while B lymphocytes are involved in humoral immunity. Bone marrows produce both T lymphocytes and B lymphocytes. However, T lymphocytes mature in thymus while B lymphocytes mature in bone marrows. There are three types of T lymphocytes as helper T cells, suppressor T cells, and cytotoxic T cells. Helper T cells activate cytotoxic T cells and B cells while cytotoxic T cells kill pathogens by phagocytosis. On the other hand, B lymphocytes produce and secrete antibodies in order to activate the immune system to destroy the antigens. B lymphocytes also have two main types: plasma cells and memory cells. Thus, this is a summary of the difference between T lymphocytes and B lymphocytes.
Reference:
1. “Biology for Majors II.” Lumen Learning, Lumen, Available here.
2. Cano, R Luz Elena. “Introduction to T and B Lymphocytes.” Current Neurology and Neuroscience Reports., U.S. National Library of Medicine, 18 July 2013, Available here.
3. “B Cells and T Cells.” Kimball’s Biology Pages, Available here.
Image Courtesy:
1. “Blausen 0625 Lymphocyte T cell (crop)” By Blausen.com staff (2014). “Medical gallery of Blausen Medical 2014”. WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436 (CC BY 3.0) via Commons Wikimedia
2. “B cell function” By Arizona Science Center – (CC BY-SA 3.0) via Commons Wikimedia