The body reacts to varicella (chicken pox virus, also called
Varicella-zoster, or Herpes zoster), not by homeostasis per se, but by
an immunological response. The body produces antibodies to neutralize
or inactivate viruses. Very simply put, when the body is exposed to
organisms (viruses, bacteria, fungi), called antigens in the
immunological reaction, the body recognizes the antigen as foreign,
triggering the immunological response.
This answer will explain homeostasis:
?The purpose of the immune system is to keep infectious
microorganisms, such as certain bacteria, viruses, and fungi, out of
the body, and to destroy any infectious microorganisms that do invade
the body. The immune system is made up of a complex and vital network
of cells and organs that protect the body from infection.
Although each type of lymphocyte fights infection differently, the
goal of protecting the body from infection remains the same. The B
cells actually produce specific antibodies to specific infectious
microorganisms, while T cells kill infectious microorganisms by
killing the body cells that are affected. In addition, T cells release
chemicals, called lymphokines, which trigger an immune response to
combat cancer or a virus, for example.?
This is one part of a several pages long series on the immune
response, and it?s well worth reading the entire series. ?The job of
your immune system is to protect your body from these infections. The
immune system protects you in three different ways:
1.It creates a barrier that prevents bacteria and viruses from entering your body.
2.If a bacteria or virus does get into the body, the immune system
tries to detect and eliminate it before it can make itself at home and
3.If the virus or bacteria is able to reproduce and start causing
problems, your immune system is in charge of eliminating it.
?Antibodies (also referred to as immunoglobulins and
gammaglobulins) are produced by white blood cells. They are Y-shaped
proteins that each respond to a specific antigen (bacteria, virus or
toxin). Each antibody has a special section (at the tips of the two
branches of the Y) that is sensitive to a specific antigen and binds
to it in some way. When an antibody binds to a toxin it is called an
antitoxin (if the toxin comes from some form of venom, it is called an
antivenin). The binding generally disables the chemical action of the
toxin. When an antibody binds to the outer coat of a virus particle or
the cell wall of a bacterium it can stop their movement through cell
walls. Or a large number of antibodies can bind to an invader and
signal to the complement system that the invader needs to be removed.?
How the Immune System Works
How Stuff Works has a great explanation of how the immune system works:
?The normal route of entry of chickenpox into a child's body is
through the mouth and nose-- usually inhaling particles that an
infected person has coughed. This means that the virus will come in
contact with the mucous membranes and trigger the beginnings of an
immune response. After this initial "alert" of the immune system, the
virus travels to the lymphatic system, where additional body defenses
are mustered. Finally, after the body has had adequate time to gear
up, the virus gains access to the blood stream and major organs. But
by this time, the immune system is mounting a full response (thanks to
its being alerted early by the mucous membranes and lymphatic system)
and will usually protect the major organs from damage from this
?After a chickenpox infection, the virus stays in the body (remains
dormant). It doesn?t do any harm because it?s kept under control by
the immune system; the part of the body that fights infection. At any
time later in life, but usually when you?re an adult, the virus can be
reactivated (come back), causing shingles.?
?Now lets talk about the humoral immune response. This refers to a
response by certain cells of the immune system (B cells) which have the
ability to make what are called antibodies. Antibodies are proteins
which float around in the blood and have a particular ability to bind
to a foreign protein. Depending on the features of this foreign
protein, antibody binding to it will have numerous possible effects.
One example would be antibodies which can recognize proteins on the
surface of invading bacteria. If antibody coats the surface of the
bacteria, the cell will more easily recognize that the bacteria is
foreign, and try to destroy it. Another example is antibody which can
recognize a certain toxin produced by bacteria and neutralize its
toxic action. An example of this is antibody against tetanus toxin.
If we get infected with the bacteria which causes tetanus, we can
usually handle the bacteria infection and rid the body of the
pathogen. The problem is that the bacteria can quickly make a potent
toxin which can make us very sick.
We need antibodies to bind the toxin and prevent it from acting.
This is why we get vaccinated against tetanus. The vaccine is
actually an inactive form of the toxin. By putting this foreign
protein in the body, our B cell recognize it as foreign and produce
antibody against it. This antibody floats around our bodies for
years, until the day we get infected by the tetanus bacteria. As soon
as the bacteria makes the toxin, the antibodies bind it, and prevent
any terrible consequences. This is an example of a humoral immune
?When bacteria or viruses get through our body?s outer defences
they may cause disease. To prevent this we have an immune system made
up of cells and molecules that are constantly on patrol looking for
and destroying foreign organisms.
For the system to be effective the cells and molecules that are
involved must be able to recognise foreign material and distinguish it
from similar chemicals that make up our tissues. This is a remarkable
feat of molecular recognition.
Any material that can trigger the immune system into action is called
an antigen. Antigens are usually the proteins, polysaccharides or
glycoproteins that are on the surface of invading bacteria or viruses.
Some of these invading pathogens produce harmful chemicals, called
toxins. Toxins may also be antigens.?
?Antibodies work by:
?binding to the antigen, making it inactive
?binding to antigens in such a way that the molecules or invading
cells clump together to form insoluble immune complexes that are
easily digested by phagocyte cells circulating in the blood and lymph
?binding to the antigens on the surface of an invading cell to form a
complex that may attract phagocytes and killer cells or activate
enzymes in the blood capable of destroying the cell.
Here is a great simple slide show, illustrating how antibodies work:
?Humoral response is responsible for blocking the infectivity of
the virus (neutralization). Those of the IgM and IgG class are
especially relevant for defense against viral infections accompanied
by viraemia, whereas those of the IgA class are important in
infections acquired through a mucosa. (the nose, the intestine). In
contrast, the cellular response kills the virus-infected cells
expressing viral proteins on their surfaces, such as the glycoproteins
of enveloped viruses and sometimes core proteins of these viruses.
Antibodies (Abs) are elicited by the surface components of intact
virions as well by the internal components of disrupted virions. Also
they are elicited by viral products built into the surface of infected
cells or released by the cells. Antibodies provide the key to
protection against many viral infections. Sometimes, they are also
pathogenic e.g. immune complexes are thought to be responsible for
causing the rash in rubella. Interactions of virions with Abs to
different components of their coats have different consequences.?
?Humans and animals infected by a herpes virus develop immunity in
the form of circulating antibody and cell-mediated immunity, including
T helper, T cytotoxic, and memory T lymphocytes (1?7). This
constellation of specific immune factors serves to protect the
infected organism from disseminated viral disease and death (8?10).
Thus, the acquired immune response to herpes viruses such as herpes
simplex virus type 1 (HSV-1) is relatively effective in protecting the
organism from morbidity or even mortality due to this virus (10?13).?
?Regarding the establishment of cell-mediated immunity following
primary corneal infection by HSV-1, it has been amply demonstrated
that cell-mediated immunity in the form of CD4+ T helper lymphocytes
and CD8+ cytotoxic T lymphocytes, which are antigen-specific for viral
HSV-1 antigens, are generated during a primary corneal infection in
patients and in experimental animals (5, 7, 28). Numerous studies in
the 1960s and 1970s demonstrated that patients who develop ocular
infection by HSV had circulating peripheral blood T lymphocytes
reactive with viral antigens in the lymphocyte transformation assay
(5, 7). Presumably, a fraction of these cells persist in patients and
in animals as a long-lived memory population that can provide a rapid
response to the threat of viral reinfection or viral reactivation. As
mentioned above, antigen-specific T lymphocytes that may be present in
the infected corneal epithelium in small numbers during primary
infection do not remain there once the infection has resolved?
For a very in-depth description of immune response to varicella:
This site has good descriptions, as well as several illustrations of
Some brief descriptions and illustrations
Scroll down near the end of the page, where it says Activation of B
cells to make antibody, for a great illustration on antibody
Immune System Structures
Here are some previous answers on immunity:
I hope this has enabled you to understand how the body fights
chickenpox, and most all viruses. If any part of my answer is unclear,
please request an Answer Clarification, and allow me to respond,
before rating. I?ll be happy to help you further on this question,
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Herpes zoster + immune response
Humoral response + varicella
immune response + varicella
immune response + varicella + antibody
immune response + varicella + antigen