S.N. |
Characteristics |
B lymphocytes (B cells) |
T lymphocytes (T cells) |
1. |
Site of Maturation |
B lymphocytes both originate and mature in the bone marrow. |
T lymphocytes mature in the thymus after its origination in the bone marrow. |
2. |
Position |
Mature B cells occur mostly outside the lymph node. |
Mature T cells occur mostly inside the lymph node. |
3. |
Distribution |
Germinal centers of lymph nodes, spleen, gut, respiratory tract; also subcapsular and medullary cords of lymph nodes. |
Parafollicular areas of cortex in lymph nodes, periarteriolar in the spleen. |
.4. |
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. |
5. |
Binds with |
Extracellular antigens such as bacteria, free viruses and other circulating free foreign material. |
The foreign antigen in association with self-antigen only such as a virus-infected cell. |
6. |
The need of Antigen Processing |
Antigen processing is not necessary. |
Antigen processing is necessary. |
7. |
Connection |
They bind directly with the antigens on the surface of the invading virus or bacteria. |
They can only bind to antigens on the outside of infected cells and not directly. |
8. |
C3 complement receptor |
Receptors for C3 complement present. |
Receptors for the C3 complement are absent. |
9. |
Cell Surface Marker |
CD19 is the cell surface markers of B cells. |
CD3 is the cell surface markers of T cells. |
10. |
Microvilli on the cell surface |
Present |
Absent |
11. |
Types of Active Cells |
They differentiate into plasma cells and memory cells. |
They differentiate into many subsets of T cells such as Cytotoxic T cells (CD8+ T cells), Helper T cells (CD4+ T cells) and suppressors cells along with memory cells. |
12. |
Abundance |
It constitutes about 20% of lymphocytes in the blood. |
It constitutes about 80% of lymphocytes in the blood. |
13. |
Secretory Product |
Antibodies are the chief secretory product of B cells. |
Cytokines (lymphokines) are the chief secretory product of T cells. |
14. |
Type of Immunity |
Involved in humoral (antibody-mediated) immunity. |
Involved in cell-mediated immunity. |
15. |
Life Span |
They have comparatively a shorter life span. |
They have a comparatively longer life span. |
16. |
Relationship |
Since B cells are also Antigen Presenting cells, they present antigens to T-cells. |
They help to activate B cells and aid in antibody production against antigens which are T-dependent. |
17. |
Functions |
Help eliminate free foreign invaders by enhancing immune responses against them; provide immunity against most foreign antigens and bacteria. |
Help lyse virus-infected cells and tumor cells; provide immunity against most viruses and intracellular bacterial pathogens; help B cells in antibody production. |