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 (Dority 2). 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 (Britannica 6). 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.
Coombs, Amy. “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.