Difference Between T Cells And B Cells

The difference between T cells and B cells is that the lymphocytes that remain in the bone marrow for differentiation are known as “B-cells,”. In contrast, the lymphocytes that migrate to the thymus are “T-cells.”  Their mode of action against fighting pathogens is different.  For example- when any pathogen enters the body, T cells recognize it, stimulate different T cells and start making clones.  This is how they increase their number and fight against pathogens.  

However, the B cells, are first activated by T cells, and they also start multiplying and creating copies of memory B cells and plasma cells that migrate to the infection site (lymph).  If the same virus or bacterium re-infects a person, memory B cells can promptly eliminate the antigens. 

Difference Between B and T Cells

What are B Cells?

B cells or lymphocytes are in charge of producing antibodies and providing humoral immunity. They make up 25% of all lymphocytes. They release cytokines that draw in additional immune cells. In reaction to the antigens, these cells develop in the bone marrow and create antibodies. B cells create memory B cells and plasma cells when they come into contact with antigens.

Antibody production occurs in plasma B cells, referred to as effector cells. Specialized cells called plasma cells make protective proteins and release them into the blood. If the same virus or bacterium re-infects a person, memory B cells can promptly eliminate the antigens since they have a lengthy lifespan. The antibody molecules might stay free or bind to a cell membrane. Therefore, B cells create antibodies or immunoglobulins (Ig) that are targeted at the pathogens that have infiltrated the body. The bone marrow produces new B-lymphocytes every few days since they have a short lifespan.

B Cells Functions

Some of the functions performed by B cells are discussed below:

• Antibody production: B cells are primarily responsible for producing antibodies.
• Antigen presentation: B cells can also present antigens to T cells, initiating immune responses and promoting coordination between different immune cells.
• Memory cell formation: B cells can differentiate into memory B cells after encountering antigens, providing long-lasting immunity upon re-exposure to the same pathogen.
• Regulation of immune responses: They can modulate immune responses by releasing cytokines and interacting with other immune cells, contributing to the regulation of inflammation and immune tolerance.

What are T Cells?

T cells control the immunological response mediated by cells, making up around 75% of the circulating lymphocytes. They originate from bone marrow hemocytoblasts, and when they move to the thymus, they are referred to as T-cells. These immature cells, known as thymocytes in the thymus, develop into T lymphocytes. Thymosin, a local polypeptide hormone, encourages this maturation process. 

After being stimulated by antigens , the T cell divides rapidly and forms a clone of cells known as lymphoblasts. These clones are morphologically similar and can react specifically with the same antigen but perform different functions.  Four different T-lymphocyte subtypes are present in the clone: Helper T-cells, Suppressor T-cells, Memory T-cells and Killer T-cells.

T Cells Functions

Some of the functions performed by T cells are discussed below:

• Directly attack and kill infected or abnormal cells.
• Regulate immune responses by activating other immune cells or suppressing excessive reactions.
• Provide long-term immunity through memory T cells, which respond rapidly to reinfection.
• Coordinate immune responses by releasing signaling molecules called cytokines.
• Help in the elimination of pathogens and infected cells through immune surveillance and activation of other immune cells.

Difference Between B-Cells and T-Cells

The difference between B cell and T cell table is given below:

Characteristics	B cells	T cells
Another name	B lymphocytes	T lymphocytes
Maturation	Bone marrow	Thymus
Percentage in the Blood	25% of the blood lymphocytes	75% of the blood lymphocytes
Lifespan	short	long
Type of Immunity	Humoral or antibody-mediated immunity (AMI)	cell-mediated immunity (CMI)
Types	Two types (plasma cells and memory cells)	Three types (helper T cells, cytotoxic T cells, and suppressor T cells)
Recognition of pathogen	It can recognize both bacterial and viral antigens	It can only recognize viral antigens
Secretion	Antibodies	Lymphokines
The movement to the Infected Site	Show movement to the site of infection.	Do not show movement to the site of infection.
Presence or absence of surface antigens	Absent	Present
Defend against	The B cells defend against bacteria and viruses in the bloodstream or lymph.	The T cells defend against pathogens including viruses, protists, and fungi that enter the cells in the body.
Location in lymph nodes	Outside	Inside
Membrane Receptor	B cell receptor (BCR)	T cell receptor (TCR)
Inhibitory effect on the immune system	The suppressor cells inhibit the immune system.	They have no inhibitory effect on the immune system

Similarities Between B Cells and T Cells

Besides differences, there are some similarities between B cells and T cells:

• Both are lymphocytes, therefore known as B and T lymphocytes.
• They are produced in the bone marrow.
• Fight against pathogens through different immunity mechanisms.
• Both B cells and T cells have antigen receptor sites on them. For example-BCR in B cells and TCR in T cells.
• Both are motile and consist of a large nucleus.
• They are found in lymphoid organs.
• Both multiply in bulk so that they can give a tough fight to pathogens.

Conclusion – Difference Between T Cells and B Cells

The difference between T cells and B cells is evident in their origin and mode of action within the immune system. B and T cells are immune cells that protect us from invading pathogens by adopting different mechanisms. B cells adopt humoral or antibody-mediated immunity (AMI) whereas T cells adopt cell-mediated immunity (CMI) to kill the pathogens. However, the basic principle remains the same, both multiply themselves to kill pathogens. Nevertheless, B cells depend upon T cells for stimulation. They also share some similarities as well.

Difference Between Related Links

Difference Between Antigen and Pathogen	Difference Between Primary and Secondary Lymphoid Organs
Difference Between Pathogen and Parasite	Difference Between Antigen and Antibody
Difference Between Humoral And Cell Mediated Immunity	Difference Between Vaccination And Immunization
Differences Between Innate and Adaptive Immunity	Difference Between Granulocytes And Agranulocytes
Difference Between Monocytes and Lymphocytes	Difference Between Primary Cell and Secondary Cell

FAQs on Difference Between T Cells and B Cells

What is the Origin of B and T Cells?

Both B cells and T cells originate in the bone marrow. But the development in case of T cells occurs in the thymus gland.

How are B and T Cells Activated and Differentiated?

Antigen presenting cells engulf microbes and interact with helper T cells. The helper T cells in turn activate the B cells which form antibodies and memory B cells.

What is the Function of B Cells?

The function of the B cells is to produce antibodies, antigen presenting cells and plays a major role in inflammatory response.

What is the Difference between B cell and T cell epitopes?

Epitopes are basically regions on the antigens that are recognized by the B and T cells. B cell epitopes are present on the surface of the antigen whereas T cell epitopes are presented by MHC I and MHC II molecules.

What are the Four Types of T Cells?

There are four types of T cells- Helper T-cells, Suppressor T-cells, Memory T-cells and Killer T-cells.