B-L ymphocytes (B-Cells)
B-cells are at the centre of the adaptive humoral immune system and are responsible for mediating the production of antigen-specific immunoglobulin against invasive pathogens. B cells are high in spleen, lymph nodes, gut, respiratory tract and bone marrow, they originate and mature in the bone marrow and constitute 20% of the total lymphocytes in the blood. B-cells bind directly with the antigens on the surface of the invading virus, pathogen or bacteria. Thereby helping to get rid of the pathogen and provide immunity against any other foreign antigens.
T-Lymphocytes (T-cells)
T-cells also referred to as T-lymphocyte is a type of white blood cell that is of key importance to the immune system and is at the core of adaptive immunity, the system that tailors the body’s immune response to specific pathogens. T cells occur in the parafollicular areas of the cortex of the lymph nodes and the periarteriolar lymphoid sheath of the spleen. They mature in the thymus after they have originated in the bone marrow and constitute 80% of the total lymphocytes in the blood.
B-cells Vs. T-cells: Key Differences
Definition
B cells also known as B-lymphocytes are a type of white blood cell of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system by secreting antibodies. However, T-cells, also known as T-lymphocytes, is a type of lymphocyte (a subtype of white blood cell) that pays a central role in cell-mediated immunity.
Site of Maturation
B cells originate and mature in the bone marrow while the T-cells mature in the thymus after they have originated in the bone marrow.
Lifespan
The lifespan of the B cells is comparatively short while the T cells have a comparatively longer lifespan.
Composition in the blood
B-cells constitute 20% of the total lymphocytes in the blood. In contrast, T cells constitute 80% of the total lymphocytes in the blood.
Function
B cells help to get rid of foreign invaders and provide immunity against most foreign antigens. In contrast, T cells lyse virus-infected cells and tumor cells, provide immunity against most viruses and bacteria and more importantly help in antibody production.
Type of Active cells
B cells differentiate into plasma and memory cells while the T-cell differentiates into many subsets of T-cell like cytotoxic T-cell (CD8+T cells), Helper T cells (CD4+ T cells), and suppressor cells along with memory cells.
Relationship
B cells are antibody presenting cells; they present antigens to T-cells. On the other hand, T cells help to activate B cells and aid in antibody production against antigens which are T-dependent.
Binding capability
B-cells bind directly with the antigens on the surface of the invading virus, pathogen or bacteria. However, T-cells can only bind to antigens on the outside of infected cells and not directly.
Inhibitory Effect
B cells do not have any inhibitory effect on the immune system whereas T-cells have an inhibitory effect on the immune system.
Movements
B-cells do not move to the site of infection whereas the T cells move to the site of infection.
Type of immunity
The B cells are involved in the humoral or the antibody-mediated immunity (AMI) while the T cells are involved in the cell-mediated immunity (CMI).
Presence of Microvili on surface
The cell surface of B cells shows cytoplasmic projections known as microvili (under the electron microscope). In contrast, the cell surface of T-cells are smooth and microvilli are absent (when observed under electron microscope).
Receptors
The B-cell receptors (BCRs) constitute of membrane antibodies known as immunoglobulin surface receptors. In contrast, surface receptors are called T-cell receptors (TCRs) and differ from membrane antibodies.
Secretory Products
Antibodies are the main secretory product of B-cells while cytokines (lymphokines) are the chief secretory product of T-cells.
Distribution
B cells are high in spleen, lymph nodes, gut, respiratory tract and bone marrow. In contrast, T cells occur in the parafollicular areas of the cortex of the lymph nodes and the periarteriolar lymphoid sheath of the spleen.
Surface Antibodies
B cells have surface antigens while the T cells lack surface antigens.
Cell Surface Maker
CD 19 is the cell surface makers of B cells while CD3 is the cell surface makers of T cells.
Action on cancerous cells or transplants
B cells do not act against cancerous cells or transplants whereas T-cells can act against cancerous cells and organ grafts.
Thymus-specific antigens
Thymus-specific antigens are absent in B-cells. However, thymus-specific antigens are present in T-cells.
C3 Complement Receptor
Receptors for the C3 complement are present on the B-cells while receptors for the C3 complement is absent in T-cells.
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DIfference B-Cells And T-Cells In Tabular Form
| Elements of Comparison | B- Cells | T-Cells |
| Definition | B cells also known as B-lymphocytes are a type of white blood cell of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system by secreting antibodies. | T-cells, also known as T-lymphocytes, is a type of lymphocyte (a subtype of white blood cell) that pays a central role in cell-mediated immunity. |
| Site of Maturation | B cells originate and mature in the bone marrow. | The T-cells mature in the thymus after they have originated in the bone marrow. |
| Lifespan | The lifespan of the B cells is comparatively short. | The T-cells mature in the thymus after they have originated in the bone marrow. |
| Composition in Blood | B-cells constitute 20% of the total lymphocytes in the blood. | T cells constitute 80% of the total lymphocytes in the blood. |
| Function | B cells help to get rid of foreign invaders and provide immunity against most foreign antigens. | T cells work against virus-infected cells and tumor cells, provide immunity against most viruses and bacteria and more importantly help in antibody production. |
| Type of Active Cells | B cells differentiate into plasma and memory cells. | T-cell differentiates into many subsets of T-cell like cytotoxic T-cell (CD8+T cells), Helper T cells (CD4+ T cells), and suppressor cells along with memory cells. |
| Relationship | B cells are antibody presenting cells; they present antigens to T-cells. | T cells help to activate B cells and aid in antibody production against antigens which are T-dependent. |
| Binding Capability | B-cells bind directly with the antigens on the surface of the invading virus, pathogen or bacteria. | T-cells can only bind to antigens on the outside of infected cells and not directly. |
| Inhibitory Capability | B cells do not have any inhibitory effect on the immune system | T-cells have an inhibitory effect on the immune system. |
| Movements | B-cells do not move to the site of infection. | The T cells move to the site of infection. |
| Type of Immunity | The B cells are involved in the humoral or the antibody-mediated immunity (AMI). | The T cells are involved in the cell-mediated immunity (CMI). |
| Presence of microvili on the surface | The cell surface of B cells shows cytoplasmic projections known as microvili (under the electron microscope). | The cell surface of T-cells are smooth and microvilli are absent (when observed under electron microscope). |
| Receptors | The B-cell receptors (BCRs) constitute of membrane antibodies known as immunoglobulin surface receptors. | Surface receptors are called T-cell receptors (TCRs) and differ from membrane antibodies. |
| Secretory Products | Antibodies are the main secretory product of B-cells. | Cytokines (lymphokines) are the chief secretory product of T-cells. |
| Distribution | B cells are high in spleen, lymph nodes, gut, respiratory tract and bone marrow. | T cells occur in the parafollicular areas of the cortex of the lymph nodes and the periarteriolar lymphoid sheath of the spleen. |
| Surface Antigens | B cells have surface antigens. | The T cells lack surface antigens. |
| Cell Surface Maker | CD 19 is the cell surface makers of B cells. | CD3 is the cell surface makers of T cells. |
| Action on cancerous cells or Transplants | B cells do not act against cancerous cells or transplants. | T-cells can act against cancerous cells and organ grafts. |
| Thymus-specific antigens | Thymus-specific antigens are absent in B-cells. | Thymus-specific antigens are present in T-cells. |
| C3 complement receptor | Receptors for the C3 complement are present on the B-cells. | Receptors for the C3 complement is absent in T-cells. |
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Similarities between T Cells and B cells
- Both B cells and T cells are lymphocytes
- Both are nonphagocytic cells.
- Both are motile cells.
- Both are found in peripheral blood and all lymphoid tissues.
- Both are involved in the adaptive immune response of an organism.
- Both are nucleated cells with large nucleus.
- Both are produced in the bone marrow.
- Both are morphologically similar.
- Both B cells and T cells can recognize the various pathogenic antigens.
Summary
B cells also known as B-lymphocytes are a type of white blood cell of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system by secreting antibodies. However, T-cells, also known as T-lymphocytes, is a type of lymphocyte (a subtype of white blood cell) that pays a central role in cell-mediated immunity.