do white blood cells protect the body from disease?
of white blood cells
The body uses the immune system to
defend its self from infections and viruses. The immune system has a series of
methods used to protect your body. The most important one are your white blood
cells or also known as leukocytes. These cells defend the body against
infection and disease by ingesting foreign materials and debris, by destroying infectious
agents and cancer cells, or by producing antibodies (Britannica 1). White blood
cells are found in lots of places throughout the body. Most are found outside
of circulation within tissue where they fight infections; the few found in the
blood stream are in transit from one site to another (Britannica 3). The white blood cells are grouped into
three major classes: Lymphocytes, Granulocytes, and Monocytes – each with a
different function (Britannica 3). As every thing else in the world, the white blood
cells can develop conditions that can have a fatal effect on a person.
Lymphocytes are really what is associated
with white blood cells. The fact that they encounter a foreign invader or
infection and destroy it. Lymphocytes are responsible for the specific
recognition of foreign agents and their subsequent removal from the host
(Britannica 4). This type of cell is then subdivided into T cells and B cells.
The B cells or B lymphocytes are what produce antibodies (Yamini 2). B cells
are like the body’s military intelligence that seek out targets and send
defense to destroy them (Yamini 2). Then there are the T cells that destroy
antigens that have been tagged by antibodies or cells that have been infected
or somehow changed (Yamini 3). T cells are like the soldiers, they destroying
the invaders that the intelligence system (B cells) has identified (Yamini 2).
Another name for T cells are actually “Killer cells”. About 25 to 35 percent of
white blood cells are lymphocytes in a healthy person (Britannica 4).
Granulocytes are the most numerous
of the white blood cells that rid the body of large pathogenic organisms such
as protozoans or helminthes and are also key mediators of allergy and other
forms of inflammation (Britannica 4). Granulocytes are subdivided into three
categories: Neutrophils, Eosinophils, and Basophils (Britannica 5). Neutrophils
are the first cell types to arrive at an infection where they engulf and
destroy the infectious micro organisms through a process called phagocytosis
(Britannica 5). Phagocytosis is when cells chew up the invading organisms (Yamini
2). Although after a neutrophil engulfs any foreign particles they
self-destruct (Dority 1). About 50 to 80 percent of all white blood cells are
neutrophils (Britannica 5). Basophils
have granules that contain a number of chemicals, including histamine that is
important in inducing allergic inflammatory responses (Britannica 5) and
heparin (Dority 2). Well what do these two chemicals do exactly? Heparin is an
anti-coagulant, meaning it prevents blood cells from clotting too quickly.
Histamine is a vasodilator that is commonly released during allergic reactions
to increase blood flow (Dority 2). Eosinophils are what destroy parasites and
also help modulate inflammatory responses (Britannica 5). How eosinophils fight
parasites are by releasing chemical mediators, peroxides, nucleases and
lipases, by a process called degranulation with target pathogens (Dority 2).
The third and final class are
monocytes. Monocytes originate in the bone marrow and develop into large
macrophages in the bloodstream (Dority 1). These cells are scavengers and are
therefore effective at direct destruction of pathogens and clean up cellular
debris from sites of infection (Britannica 6). In other words, monocytes are
what clean up the mess left behind from the destruction of a foreign invader. Between
4 and 8 percent of white blood cells are monocytes in your blood (Britannica 6).
White blood cells are also apart of
another system known as the lymphatic system. This system is made up of lymph
nodes that work like filters to remove any germs that could make you sick, in
this case it’s a clear fluid called lymph that contains leukocytes (white blood
cells) inside of it (article 2 pg.1).
All of these different classes and
subdivisions of white blood cells aren’t because there are so many. Its because
specific types of cells are associated with different illnesses which reflect
the special function of that cell type in body defense (Britannica 6). This is
seen in newborns who have a high white blood cell count that gradually to the
adult level during childhood. This is a natural response as newborns are more
susceptible to getting an infection (Britannica 6).
How do white blood cells know then
when it s time for them to destroy a foreign invader? It was found that white
blood cells make a protein called HIF-1 that boost the production of
antibacterial compounds when oxygen levels begin to drop, or when the cell
encounters a harmful bacterium (Coombs pg.1). “turning on the HIF-1 is like a
white blood cell pulling out it’s sword as it enters infected tissue” (Coombs
pg. 1). Therefore, if they were always making killer compounds it might destroy
the good cells and waste good energy (Coombs Pg.1).
Some people have problems with their
immune system meaning it may respond to non-dangerous materials in a
potentially pathogenic way. Allergies, an example of this is when the immune
system overreacts and treats something harmless like peanuts as though is was
really dangerous to the body (article 2 pg.2). Well what is it that causes
this? Its certain medical conditions such as lupus that cause the immune system
to fight the good cells and this can cause problems (Britannica Pg.2).
The immune system is a well regimented army
working together to combat the dangerous foreign invaders. Its battalions
consist of front line white cells in the form of neutrophils, Special operations
white cells in the form of basophils and finally eosinophils. Together these
types of cells are what make up granulocytes cells that rid body of disease. While
the lymphocytes are what find diseases or infections and tell the granulocytes
to destroy them.
“Killer Cells Get a Boost.” Science Now, 7/1/2005,
p. 1. EBSCOhost,
Dority, Jason. “White Blood
Cells & Their Functions.” LIVESTRONG.COM, Leaf Group, 14 Aug.2017, www.livestrong.com/article/106131-white-blood-cells-functions/.
“Immune System.” Edited by
Yamini Durani, KidsHealth, The Nemours Foundation, May 2015, kidshealth.org/en/parents/immune.html.
The Editors of Encyclopædia
Britannica. “White blood cell.” Encyclopædia Britannica Encyclopædia Britannica, inc., 16 Feb. 2017, www.britannica.com/science/white-blood cell.
“Your Immune System.” Edited
by Yamini Durani, KidsHealth, The Nemours Foundation, May 2015, kidshealth.org/en/kids/immune.html.