Difference between T Cells and B Cells

The body is made up of different cells and each type of cell has important functions. In this article, we are going to discuss T cell and B cells; their roles and differences.

 

T cells are a component of lymphocytes

Picture 1: T cells are a component of lymphocytes.

Image Source: wikimedia.org

 

T cells helps fight off cancer cells

Picture 2: T cells helps fight off cancer cells.

Image Source: verywellhealth.com

 

What are T cells?

T cells are white blood cells vital to the immune system. They are like soldiers that identify and destroy invaders. They are called T cells because they mature in the thymus. T cells are also called T lymphocytes. (1, 2)

 

What are the types of T cells?

  1. Killer T cells – These T cells have x-ray vision. They can see the inside of the body’s own cells by scanning the surface. They can easily hunt and destroy infected cells.
  2. Helper T cells – These T cells assist in immune response.
  3. Suppressor T cells – These T cells block the actions of other types of lymphocytes.

 

What are the roles of T cells?

  1. They destroy infected/harmful cells.
  2. They scan the inner structure of foreign invaders.
  3. They help eradicate cancer cells.
  4. They have the ability to remember invaders they encountered a long time ago.
  5. They help other immune cells in detecting and ingesting harmful cells.
  6. They are responsible for immune response leading to rejection of transplanted organ, allergic reactions, autoimmune diseases such as rheumatoid arthritis and diabetes. (1, 2, 3, and 4)

closer look at B cells, a component of lymphocyte

Picture 3: A closer look at B cells, a component of lymphocyte.

Image Source: wikimedia.org

 

What are B cells?

B cells are white blood cells that protect the body from infection. They originate from the hematopoietic stem cells inside the spongy bone marrow. Once they mature, they travel to the blood and other parts of the body such as the lymph nodes. (5, 6)

 

What are the roles of B cells?

  • They are involved in the body’s response to foreign invaders through humoral immunity.
  • They signal other immune cells to destroy the invaders.
  • Some activated B cells become memory cells and live in the bone marrow, spleen, and lymph nodes. They have the ability to remember antigens they encountered in the past. Hence, B cells give long-lasting immunity to various invaders.
  • They ensure cell specificity.
  • They regulate the construction of antigen receptors.
  • They play a vital role in antibody production.
  • They export all the needed cells in the periphery.
  • They help in rearranging antigen receptors. (5, 6, and 7)comparison image of differences between T cells and B cells

Picture 4: A comparison image between T cells and B cells.

Image Source: askabiologist.asu.edu

 

Difference between B cells and T cells

Originate

  • T cellsThey are lymphocytes that originate in the bone marrow and mature in the thymus.
  • B cellsThey are lymphocytes that originate and mature in the bone marrow.

Position

  • T cellsThey are positioned inside the lymph nodes.
  • B cellsThey are positioned outside the lymph nodes.

Where they recognize antigens

  • T cells They recognize antigens found outside of the infected cells.
  • B cells – They recognize antigens found on the surface of antigens. (8, 9)

Membrane Receptor

  • T cells TCR receptor
  • B cells BCR receptor

Distribution

  • T cells They are distributed in the lymph nodes specifically in the parafollicular area of the cortex and the periarteriolar lymphoid sheath of the spleen.
  • B cells – They are distributed in the germinal centers, subcapsular and medullary cords of the lymph nodes, gut, spleen, and respiratory tract. (8, 9)

Presence of surface antibodies

  • T cellsThey do not have surface antibodies.
  • B cellsThey have surface antibodies.

Life Span

  • T cells They have a long lifespan.
  • B cellsThey have a short lifespan.

Type of secretion

  • T cells They secrete lymphokines.
  • B cellsThey secrete antibodies. (9, 10)

Composition/proportion in the blood

  • T cells – 80% of the blood lymphocyte is composed of T cells.
  • B cells20% of the blood lymphocyte is composed of B cells.

Type of immunity

  • T cells Cell-mediated immunity.
  • B cellshumoral/antibody-mediated immunity

Types

  • T cellsThere are three types: helper T cells, killer T cells, and suppressor T cells.
  • B cellsThere are two types: plasma cells and memory cells.

Response to the infected site

  • T cellsThey move right away to the infection site.
  • B cells They do not move to the infection site.

Reaction to transplant and tumor cells

  • T cellsThey act against the transplant and tumor cells.
  • B cellsThey do not act against transplant and tumor cells.

Inhibitory effect

  • T cellsA particular type of T cell, specifically suppressor T cell has an inhibitory response to the immune system.
  • B cellsThey do not have an inhibitory response to the immune system. (8, 9, and 10)

What they fight against?

  • T cells They fight almost all pathogens which include but not limited to viruses, fungi, and protists that enter the body.
  • B cells They fight against viruses and bacteria in the lymph and bloodstream.

 

Refer to the table below for a detailed comparison between T cells and B cells.

Key differences

T cellsB cells
OriginateOriginate in the bone marrow and mature in the thymusOriginate and mature in the bone marrow
Type
  • Helper t cells
  • Killer t cells
  • Suppressor t cells
  • Plasma cells
  • Memory cells
Position/locationinside the lymph nodesoutside the lymph nodes
Where they recognize antigenOutside the infected cellsOn the surface of antigen
Membrane receptor TCR receptorBCR receptor
DistributionParafollicular area of the cortex and the periarteriolar lymphoid sheath of the spleenThe germinal centers, subcapsular and medullary cords of the lymph nodes, gut, spleen, and respiratory tract
Lifespan LongerShorter
Presence of surface antibodiesNonePresent
Type of secretion LymphokinesAntibodies
Type of immunityCell-mediated immunityhumoral/antibody-mediated immunity
Proportion in the blood80% of blood lymphocyte20% of blood lymphocyte
Response to the infected siteMove right away to the infection siteDo not move to the infection site
Reaction to transplant and tumor cellsAct against the transplant and tumor cellsDo not act against transplant and tumor cells
Inhibitory effect Some T cells inhibit the response to the immune systemDo not have the inhibitory response to the immune system
What they fight against
  • Viruses
  • Fungi
  • Protists
Viruses and bacteria in the lymph and bloodstream (8, 9, and 10)

References

  1. https://en.wikipedia.org/wiki/T_cell
  2. https://www.medicinenet.com/script/main/art.asp?articlekey=11300
  3. https://www.immunology.org/public-information/bitesized-immunology/cells/helper-and-cytotoxic-t-cells
  4. https://askabiologist.asu.edu/t-cell
  5. https://en.wikipedia.org/wiki/B_cell
  6. https://www.immunology.org/public-information/bitesized-immunology/cells/b-cells
  7. https://www.medicinenet.com/script/main/art.asp?articlekey=2413
  8. https://www.researchgate.net/publication/320182585_Difference_Between_T_Cells_and_B_Cells
  9. https://education.seattlepi.com/functional-difference-between-t-cells-b-cells-4573.html
  10. https://biodifferences.com/difference-between-t-cells-and-b-cells.html

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