Healthy Bone Marrow Cells And Your Immune System

Bone marrow is one of the components of your body’s complex immune system. One of the most important functions of the bone marrow is to produce white blood cells, some of which stimulate the production of antibodies that help your body fight off infection.

What Is Bone Marrow?

Bone marrow is the soft, spongy tissue found in the hollow center of large bones. Bone marrow can be one of two types: red marrow or yellow marrow. When you’re born, all your bone marrow is red. As you age, though, an increasing amount of your bone marrow becomes yellow marrow. Most of the bone marrow cells in yellow marrow are fat cells.

The bone marrow of an average adult is about one-half red and one-half yellow marrow. Red marrow is found mainly in flat bones such as the hipbone, breastbone and ribs, and at the ends of long bones such as the femur.

Healthy Bone Marrow Cells

Red bone marrow contains stem cells that produce three main types of blood cells, each with a different function:

  • Platelets (thrombocytes) form blood clots to help control bleeding.
  • Red blood cells (erythrocytes) transport oxygen from the lungs to other organs and carry carbon dioxide from the organs back to the lungs for removal.
  • White blood cells (leukocytes) help the body to fight off infection.

White Blood Cells

White blood cells are among the most significant components of your entire immune system. All white blood cells are produced in the bone marrow. Unlike other body cells, white blood cells can move around and seize other cells and bacteria by engulfing them whole: an effective strategy for fighting infection. White blood cells can’t reproduce on their own.

White blood cells can be divided into three subgroups: granulocytes, lymphocytes and monocytes. Lymphocytes consist of B- and T-lymphocytes. Both are involved in fighting bacteria and viruses, but each has a different role. Some T-lymphocytes have earned the name “Killer T cells” for their ability to detect and destroy viruses by bumping up against them. Two other types of T cells called Helper T cells and Suppressor T cells keep these Killer T cells in check.

B-lymphocytes mature into blood plasma cells that produce antibodies. Each B-cell is highly specified to recognize only one specific pathogen or antigen. When an antigen enters the body, the B cell turns into a blood plasma cell that rapidly reproduces itself to produce millions of antibodies that eliminate the antigen.

Healthy Bone Marrow Cells Produce Antibodies

Antibodies are complex proteins that target a specific antigen. Antigens such as bacteria, toxins or viruses cause the immune system to produce antibodies. Each individual antibody is shaped like the letter Y with a binding site on each arm of the Y that matches only one type of antigen. Different classes of antibodies can incorporate different configurations of multiple antibodies, such as IgM antibodies (formed as pentamers, or groups of five antibodies).

Antibodies bind to the invading antigens, thus preventing them from destroying any more of the body’s cells. Once the invading particle is disabled, other immune cells move in to destroy it.

Resources

Mayo Foundation for Medical Education and Research. (2009). Multiple myeloma: Causes. Retrieved September 24, 2010, from http://www.mayoclinic.com/health/multiple-myeloma/DS00415/DSECTION=causes

Myeloma Institute for Research and Therapy. (n.d.). Basic pathology concepts of multiple myeloma. Retrieved September 24, 2010, from http://myeloma.uams.edu/about-myeloma/pathology.asp

National Cancer Institute. (2008). What is multiple myeloma? Retrieved September 23, 2010, from http://www.cancer.gov/cancertopics/wyntk/myeloma/page2

Seattle Cancer Care Alliance. (n.d.). Multiple myeloma facts. Retrieved September 24, 2010, from http://www.seattlecca.org/diseases/multiple-myeloma-facts.cfm