Viruses and immune function

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Antibody: a molecule made by B-cells to trap foreign particles and microbes...more

Molecule: a chemical structure that has two or more atoms held together by a chemical bond. Water is a molecule of two hydrogen atoms and one oxygen atom (H2O)... more

Plasma cell: an immune cell that comes from B-cells and makes and releases antibodies.

Receptor: a molecule on the surface of a cell that responds to specific molecules and receives chemical signals sent by other cells.

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duck anatomy, thymus and bursa of fabricius


You might think B-cells got their name because they are made inside your bones. It is true that most blood cells are made inside the bone marrow, but that is not where the “B” in B-cells came from. Their name comes from the name of the place they were discovered, the Bursa of Fabricius. The Bursa is an organ only found in birds.

B Cell character

Unlike T-cells and macrophages, B-cells don’t kill viruses themselves. In the Viral Attack story, the B-cell sweeps up the leftover viruses after the T-cell attack. Actually, B-cells are as important as T-cells and are much more than just a final clean-up crew. They make important molecules called antibodies. These molecules trap specific invading viruses and bacteria. Without this line of defense, your body would not be able to finish fighting most infections. 

B-cell, T-cell, what’s the difference?

Just like T-cells, each B-cell has a receptor that will connect to only one antigen shape. And, like T-cells, B-cells that recognize self-antigens are destroyed, so they don’t harm your body’s healthy cells.

B and T cell comparison


An important difference between T-cells and B-cells is that B-cells can connect to antigens right on the surface of the invading virus or bacteria. This is different from T-cells, which can only connect to virus antigens on the outside of infected cells.

Your body has up to 10 billion different B-cells. They’re too small to see with your eyes, but if you lined them all up, they’d be longer than 100 soccer fields. With so many different B-cells patrolling your body, you are ready to fight almost any invader.

B-cells become plasma cells

When a B-cell receptor connects to its specific antigen, a Helper T-cell releases chemicals that tell that B-cell to divide many times. This makes an army of B-cells with the perfectly shaped B-cell receptor to connect to the invader in your body.

Many of these B-cells quickly turn into plasma cells. Plasma cells make and release antibodies that connect to the same antigen as the original B-cell receptor. Plasma cells make thousands of antibodies per second, which spread throughout your body, trapping any viruses they see along the way.

B-Cell maturation


What do antibodies do?

macrophage and antibodies


Antibodies trap invading viruses or bacteria in large clumps. This makes it easy for macrophages to eat them. Antibody-coated viruses are called “neutralized” because they can’t infect your cells.

Even after you have fought off your infection, some antibodies stay in your blood. If that virus tries to infect you again, your immune system has a head start trapping it.

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Bibliographic details:

  • Article: B-cells
  • Author(s): Dr. Biology
  • Publisher: Arizona State University School of Life Sciences Ask A Biologist
  • Site name: ASU - Ask A Biologist
  • Date published: February 16, 2011
  • Date accessed: May 21, 2024
  • Link:

APA Style

Dr. Biology. (2011, February 16). B-cells. ASU - Ask A Biologist. Retrieved May 21, 2024 from

American Psychological Association. For more info, see

Chicago Manual of Style

Dr. Biology. "B-cells". ASU - Ask A Biologist. 16 February, 2011.

MLA 2017 Style

Dr. Biology. "B-cells". ASU - Ask A Biologist. 16 Feb 2011. ASU - Ask A Biologist, Web. 21 May 2024.

Modern Language Association, 7th Ed. For more info, see
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