B-Cells vs T-Cells
(Similarities and Differences between B-Lymphocytes and T-Lymphocytes)
Lymphocytes are the key cells of the immune system and they are responsible for the adaptive immune response of an organism. They are also responsible many of the immunological characteristics such as specificity, diversity, memory and self/non-self recognition. Lymphocytes constitute about 20 – 40% of the body’s White blood cells and 99% of the cells of the lymph. Lymphocytes are broadly classified into THREE populations based on their function, lifespan, cell surface components and most importantly their place of maturation. They are B-Lymphocytes (B-Cells), T-Lymphocytes (T-Cells) and Natural Killer Cells (NK Cells).
B-Lymphocytes (B-Cells): They mature in the bone marrow or bursa (in birds). B-cells possess membrane bound immunoglobulins which acts as the receptors for the antigens. They are involved in the humoral (antibody mediated) immune responses.
Learn more: Cell Mediated vs Humoral Immunity
T-Lymphocytes (T-Cells): They mature in the thymus, hence the name. T-cells possess receptors for antigens on their surface but it is structurally different from immunoglobulins. They are involved in Cell-mediated immune responses.
The present post discusses the Similarities and Differences between B-Lymphocytes (B-Cells) and T-Lymphocytes (T-Cells) with a Comparison Table.
Similarities between B-Cells and T-Cells
$. Both B-cells and T-cells are lymphocytes.
$. Both are the descendants of lymphoid progenitor cells.
$. Both are produced in the bone marrow.
$. Both are nucleated cells with a large nucleus.
$. Both are motile cells.
$. Both are nonphagocytic cells.
$. Both are found in peripheral blood and all lymphoid tissues.
$. Both are involved in the adaptive immune response of an organism.
$. Both B-cells and T-cells are morphologically similar (cannot be distinguished morphologically under the light microscope).
Difference between B-Cells and T-Cells
Sl. No. B-Lymphocytes (B-Cells) T-Lymphocytes (T-Cells)
1 B-cells mature in the bone-marrow. T-cells mature in the thymus.
2 B-cells constitutes 20% of the total lymphocytes in the blood. T-cells constitutes 80% of the total lymphocytes in the blood.
3 B-cells are involved in the humoral immune response. T-cells are involved in the cell mediated immune response.
4 Mature B cells occur outside the lymph node. Mature T cells occur inside the lymph node.
5 The sub-populations of B-cells are Memory cells and Plasma cells. The sub-populations of T-cells are Cytotoxic T cells, Helper T cells and Suppressor cells.
6 B-cells can synthesize antibodies. T-cells can synthesize lymphokines such as IL2, IL4, IL5 and γ-interferon.
7 CD19 is the cell surface marker of B-cells. CD3 is the cell surface marker of T-cells.
8 B-cells are capable of binding to antigens. T-cells are not capable of binding to antigens directly. They require antigen presentation.
9 Thymus-specific antigens are absent in B-cells. Thymus-specific antigens are present in T-cells.
10 The lifespan of B-cell is comparatively short. The lifespan of T-cell is comparatively long.
11 B-cells do not move towards the site of infection. T-cells can move towards the site of infection.
12 B-cells can recognize the antigens on the bacterial and viral surfaces. T-cells can recognize antigens only one the outside of the infected cells.
13 B-cells recognize antigens through membrane-bound antibodies called B-cell receptor or BCR. T-cells recognize antigens through T-cell receptors (TCR) on the membrane.
14 IgM is present on the surface of B-cells.
IgM is absent on the surface of T-cells.
15 B-cells possess the receptors for the FC fragments of IgG. T-cells does not possess the receptors for the FC fragment of IgG.
16 Receptors for the C3 complement is present on the B-cells. Receptors for the C3 complement is absent in T-cells.
17 SRBC rosette is absent in B-cells. SRBC rosette is present in T-cells.
18 The cell surface of B-cells shows cytoplasmic projections called microvilli (under the electron microscope). The cell surface of T-cells are smooth and microvilli are absent.
18 Blast formation in B-cells can be seen after the interaction with bacterial endotoxin and Epstein-Barr virus. Blast formation in T-cells can be seen after the treatment with mitogens such as Concanavalin A (Con A) or Phytohemagglutinin (PHA).
20 B cells do not act against cancerous cells or grafts. T-cells can act against cancerous cells and organ grafts.
Parija S.C, (2016), Textbook of Microbiology and Immunology, Elsevier
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