The Human Immune System: Basics and then some

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The Human Immune SystemBasics and then some
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Basic Components of the Immune System

• Pathogen, Bacteria, Viruses, Infections, and
  parasites
• Leukocytes
• Antibodies
• Antigens

Virus
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Pathogens and all the other stuff

• Any biological agent that causes illness and/or
  disease to its host. Also known as a germs,
  simple as that!

Different types of pathogens include the
following
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White Blood Cells
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Eosinophils and Macrophages
Eosinophils are a type of White Blood Cell. They
fight infection and parasites. They also play a
role in Allergic reactions. Eosinophils produce
Interleukin 1 and Interleukin 2 (To be explained
later as well).

• Macrophage, Big Eaters, a form of White Blood
  Cell.
• Operates in both the Non-specific and Specific
  Immune Systems (to be explained later)
• Also a Phagocyte, which means it engulfs
  pathogens and cellular debris, and then proceeds
  to digest it, this process is known as
  Phagocytosis.

Macrophage!
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Antibodies Antigens
Antibodies are produced by B cells, when
stimulated by lymphokines from helper T cells.
The antibody attaches to the antigen, completing
the signal, coding the infected cells for
destruction. Antibodies are constructed of DNA
fragments, making them so unique and almost
innumerable.

• Antigens a fragment of a protein or peptide from
  the pathogen, taken to the surface of the
  infected cell and bound in an MHC (major
  histocompatibility complex) molecule.
• The class 1 MHC complex molecule and the foreign
  peptide form the antigen, which can be read by
  the receptors on Killer T cells.

Antigen
Cell
Class 1 MHC molecule
Pathogen
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T cells!
Killer T cells- They find specifically coded
infected cells, and then destroy them with
cytotoxins. They may be directed by Helper T cells
Helper T cells- secrete lymphokines that direct B
cells into producing antibodies and also direct
the Killer T cells as to which cell they get to
eliminate.
Memory T cells- derived from Helper T cells, have
the same properties as their parent cell, and
circulates until the body encounters the pathogen
its parent cells were designer for.
Suppressor T cells- in charge of slowing and
stopping the immune response after the foreign
substance is destroyed.
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B cells

• B Plasma Cells- when the B cell produces the
  antibody for a specific antigen, it begins to
  clone itself into B plasma cells, that produce
  more of that particular binding antibody.
• These cells release immunoglobulin, or
  antibodies.
• B plasma cells have a 5 to 7 day life-span
• all its protein synthesis energy is going into
  the production of Antibodies, not self
  preservation.

• B Memory Cells- These are the same as B plasma
  cells, except they remain inactive until the
  secondary immune response
• Secondary immune response is considered anytime
  the body encounters a pathogen after the first
  time. Quicker response time.
• Primary response is the first time the body
  encounters a specific pathogen, Lag period before
  B cells respond.

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NK Cells

• NK, stands for Natural Killers, meaning they do
  not need to be activated by a class 1 MHC
  receptor
• NK cells play a major role in the Innate Immune
  System
• Activated by interferons and macrophage-derived
  cytokines
• Contains a virus until killer T cells develop,
  and then kills the virus.

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Now, the pieces come together
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Non-Specific Immune Response

• Also Known as the Innate Immune System
• Consists of
• Complement system, and three response types
• Fever Response,
• Inflammatory Response,
• Interferon Response

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Inflammatory Response

• Occurs from Trauma.
• Releases Bradykinin
• Causing release of histamines.
• Histamine causes increased capillary dilation,
  subsequently increasing capillary permeability.
• Increase in fluids causes inflammation!

Bradykinin is a protein that stimulates pain
sensors as well as causing the release of
histamines
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Interferon Response

• As the name suggests, they interferewith viral
  replication!
• Once the virus infects the cell, the cell creates
  a chemical protein called Interferon!
• Interferon inhibits viral reproduction between
  cells by binding to the receptors of uninfected
  cells.

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Fever Response

• The response to toxins in the body, produced by
  bacteria, is to increase the internal temperature
  of the body.
• This affect is enhanced when cells release
  Pyrogen, a cytokine that resets the bodies temp.
  Also known as Interleukin 1!

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Complement System

• Main component of the Innate Immune System
• 3 primary ways to dispose of pathogens.

1.)Chemical stimulation causes the complement
protein to bind with any cell, like bacteria.
Binding triggers activation of other complements,
as well as attracting phagocytes. Complements
can kill bacteria by punching a hole into their
lipid membrane and essentially drowning them in
water.
2.) Some cells have sugar (polysaccharide)
capsule shells, complement cant directly
bind. So theyre either eaten by macrophages, or
3) bound to a macrophage that then releases
IL-6, IL-6 goes to the liver and produces a
protein called Mannose. Mannose binds to the
bacteria, allowing a complement to bind to it as
well.
Foreign Cell
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Interleukins
Of Note Interleukin 1, 2, and 6

• A form of cytokine, they act like
  neurotransmitters for the immune system, relaying
  messages.

• Interleukin 1
• Responsible for fever response
• Controls some lymphocytes
• Increases the number of bone marrow cells
• Causes degeneration of joints between bones

Interleukin 6 -Secreted by macrophages, and sent
to liver to produce Mannose, which is a protein
that binds to sugars. - Helps with inflammation,
especially from burns
Interleukin 2 -Key in discriminating between
Self and foreign cells -Secreted by the binding
of T cells to an antigen - Stimulates growth,
differentiation, and survival of killer T cells.
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Specific Immune Response

• Also known as Adaptive Immune System
• Breaks down into two categories-
• Antibody- Mediated Immune Response (AMIR)
• Cell-Mediated Immune Response (CMIR)

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Antibody Mediated Immune Response

• Also known as Humoral Immune Response
• The antibodies secreted by the B cells in AMIR
  attach to antigens and effectively tag specific
  cells for destruction, sparing the lives of the
  healthy cells.

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Flow of AMIR
Macrophages roam body, engulfing infected
extracellular materials
Degrades engulfed material into peptides
Class 2 MHC presents the infected peptide As an
Antigen
Antigen received by Helper T cells
Macrophage returns to lymph nodes w/ antigen
Th Cells secrete lymphokines
Lymphokines direct B cells to release
antibodies And directs Tk cells to infected cells.
Tk kills infected cells tagged by antibodies
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Flow of CMIR
Host cells carry class 1 MHC molecules to outside
of cell
MHC binds to and displays peptide/protein
fragment of pathogen
Parasite and MHC form antigen
Antigen recognized by Killer T cell antigen
receptors
Killer T cell releases cytotoxins into infected
cells, and kills them
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Immunological Memory

• The reason why vaccines make sense, and we
  eventually build a tolerance to certain diseases

Vaccination is an introduction of a dormant or
dead pathogen, which allows are body to do its
primary immune response without the risk of
actual sickness.
Its because after every encounter with a
pathogen, both the T cells and the B cells
differentiate into an inactive form of their
parent cell. They remain inactive until the
second immune response for that specific pathogen.
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Allergic reactions

• The allergy is the immune systems response to a
  harmless foreign substance, such as pollen or
  dust.
• Since the immune system is based primarily off of
  DNA, then it can be inferred that allergies are
  hereditary.

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Self vs. Not Self

• Like most systems things can go wrong, such as
  when the immune system attacks itself, not
  recognizing the proteins that code a cell as
  self. When this happens it is known as an
  autoimmune disease.
• In the case of tissue implants, they may be
  rejected if the tissue cells dont have the
  proper proteins to inactivate the complement
  system in a different humans body. So the
  complement kills the cells!
• In order for tissues to be accepted they also
  must have the proper MHC complex to pass as human
  cells, these proteins must be on the surface of
  the cells, as either of the two classes.

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The Immune System presented differently
Immunological memory
CMIR
AMIR
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Bibliography-Information

• http//www.mmu.k12.vt.us/teachers/kefferm/humanbio
  /immune/how20cells20process20Ag.pdf
• http//www.mmu.k12.vt.us/teachers/kefferm/humanbio
  /immune/white20blood20cells20writing.jpg
• http//en.wikipedia.org/wiki/Immune_System
• http//en.wikipedia.org/wiki/Pathogen
• http//en.wikipedia.org/wiki/Cell-mediated_immunit
  y
• http//en.wikipedia.org/wiki/Humoral_immune_respon
  se
• http//en.wikipedia.org/wiki/Cytokine
• http//en.wikipedia.org/wiki/Interleukins
• http//en.wikipedia.org/wiki/Interleukin_1
• http//en.wikipedia.org/wiki/Interleukin_2
• http//en.wikipedia.org/wiki/Lymphokine
• http//en.wikipedia.org/wiki/Eosinophil_granulocyt
  e
• http//en.wikipedia.org/wiki/Natural_killer_cell
• http//en.wikipedia.org/wiki/Lymphocyte
• http//en.wikipedia.org/wiki/MacrophagePhagocytos
  is
• http//en.wikipedia.org/wiki/Allergy
• The Human Biology Text book by Joseph Mannino
• http//uhaweb.hartford.edu/bugl/immune.htm
• http//en.wikipedia.org/wiki/Antibody

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Bibliography-Pictures

• https//services.epnet.com/GetImage.aspx/getImage.
  aspx?ImageIID2508
• http//www.mmu.k12.vt.us/teachers/kefferm/humanbio
  /immune/how20cells20process20Ag.pdf
• http//mmsmineraldrops.com/images/pathogens3.jpg
• http//en.wikipedia.org/wiki/Lymphocyte
• http//www.bio-pro.de/imperia/md/images/artikelgeb
  unden/stern/nk_tumor_338x319.jpg
• http//uhaweb.hartford.edu/bugl/immune.htm
• http//tell.fll.purdue.edu/JapanProj/FLClipart/Ver
  bs/fever.gif
• http//static.howstuffworks.com/gif/light-virus-1.
  jpg
• http//www.lipidnutrition.com/Images/MPE_059_gs20
  copy20adjusted20pixels_tcm7-3751.jpg
• http//pathology.emory.edu/images/FacultyImages/Co
  operM.jpg
• http//www.gtdtimes.com/files/2008/05/memory.jpg
• http//upload.wikimedia.org/wikipedia/commons/4/4a
  /Hematopoiesis_simple.png
• http//www.modernforager.com/blog/wp-content/uploa
  ds/2008/03/96500b.jpg

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Words of the Day!

• Erythropoietin- glycoprotein that controls red
  blood cell production.
• Haematopoiesis- the process of making blood cells
  from hematopoietic stem cells.
• Agammaglobulinemia- the inability to make
  antibodies

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And then theres this guy