Differences between B Cells and T Cells

 

Differences between B Cells and T Cells

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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.