Nonspecific Defenses: Innate Immunity

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CHAPTER 24
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Nonspecific
DefensesInnate Immunity
24.1

Components skin, sweat, saliva, tears, mucous
membranes lining organ systems that open to the
external environmentdigestive/respiratory/
genitourinary, stomach acid, nose hair, cilia
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• Innate defensive cells
• Phagocytes white blood cells that eat bacteria
  foreign materials that enter the body
• Neutrophils engulf microbes in infected tissue
• Macrophages develop from monocytes phagocytize
  bacteria virus-infected cells,they wander
  actively in interstitial fluid

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Natural Killer Cells attack cancer cells
virus infected cells by releasing chemicals that
promote apoptosis (AKA-programmed cell
death) NOTE All types of these white blood
cells leave the blood scavenge invading
cells in the interstitial fluid body tissues
Not phagocytic
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Innate defense by proteins either attack
microbes directly or impede their
production Interferons proteins produced by
virus-infected cells that help other cells resist
viruses (Fig. 24.1B p. 486) Complement system
about 30 proteins that circulate in the blood
plasma and work with other defense mechanisms
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24.2

• Inflammatory Response
• Any damage to tissue (microorganisms or physical
  injury) triggers this response, injured cells
  release histamine this causes the blood vessels
  in vicinity to dilate become leakier

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WBCs that rushed to the area engulf
microorganisms clean up debris pus dead WBCs
that accumulate in area, along w/fluids
Response to an infection may be localized or
systemic systemic infection is widespread so
more WBCs will circulate,fever (good and/or bad)
may result
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THE LYMPHATIC SYSTEM
Components Lymphatic system consists of
branching network of vessels, lymph nodes,
thymus, tonsils, appendix, spleen, bone marrow
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Lymphatic vessels carry a fluid called
lymph. Lymphatic system has 2 main
functions 1return tissue fluid to
circulatory system 2fight infections
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• Circulation of Lymph
• Lymph enters system through open lymphatic
  capillaries
• Largest lymph ducts (R lymphatic duct thoracic
  duct) empty into circulatory systems veins in
  shoulders
• As lymph circulates, microbes from infected sites
  cancer cells can be phagocytized by macrophages

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The Immune Response

• The Immune System
• When the nonspecific defense mechanisms fail, the
  immune system provides another line of defense
• - usually more effective than nonspecific
• - can amplify certain nonspecific responses

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The immune system recognizes foreign materials
in the body - foreign invaders are called
antigens - can include certain molecules on the
surfaces of viruses, bacteria, mold spores,
cancer cells, pollen

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Bacteria Bad Boys

• Bacillus anthracis anthrax
• Bordetella petussis whooping cough
• Clostridium botulinum botulism
• Clostridium tetani tetanus
• Escherichia coli acute pyelonephritis
• Lactobacillus acidophilus cavities
• Neisseria gonorrhoeae gonorrhoea
• Salmonella typhimurium food poisoning
• Streptococcus mutans cavities
• Streptococcus pneumoniae pneumonia
• Treponema pallidum syphilis
• Vibrio cholerae cholera

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• Antibody - a protein found in blood plasma that
  attaches to one particular kind of antigen
  helps counter its effects
• - antibodies do not recognize the whole
  antigen, only the localized region on the surface
  known as the antigenic determinant

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• binding sites on the antibody
• antigenic deter-
• minant have
• complementary
• shapes
• (lock key)

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Immunity means resistance to specific invaders -
acquired by natural infection, or - acquired by
vaccination (weakened or inactive form of the
pathogen)
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2 TYPES
1. Active immunity - achieved either naturally
or artificially when foreign materials enter the
body
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2. Passive immunity - achieved when antibodies
pass from mom to fetus or to a nursing newborn or
when travelling (GG shots)
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The Immune Response
Cells of the Immune System Lymphocytes - WBCs
that produce the immune response,they come
from stem cells in bone marrow.
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-some lymphocytes continue to develop in bone
marrow become specialized B cells -others
are carried by blood to thymus become
specialized as T cells -humans can have 100
million to 100 billion different B cells T
cells
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B cells provide humoral immunity -B cells
secrete antibodies that are carried by blood
lymph to the site of infection -this system
defends against bacteria viruses present in
body fluids -can be transferred passively by
plasma donation
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T cells provide cell-mediated immunity -defends
against bacteria, viruses, fungi, protozoans,
cancer cells inside body cells -circulate in
blood mount a cellular attack on repeated
foreign invaders
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• Both T B cells must mature before they are able
  to function in defense of the body
• - must be able to recognize respond to a
  specific antigen

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• must have specialized regions on their
• surface known as antigen receptors

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• Both T B cells will make memory cells in
  response to an antigen
• - they are activated by a second exposure to an
  antigen
• - seem to confer life immunity (measles,
  chicken pox)

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The Immune Response

• Humoral Immunity
• response is mediated by the production of
  antibodies made by B cells
• each antibody is made of 4 polypeptide chains 2
  heavy 2 light chains (this gives it a Y shape)

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• Each of the 4 chains of the antibody has a
  constant (C) region
• - constant role in destroying invading cells is
  to mark them for destruction (opsonization)
• - phagocytes will then destroy the antigen

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• Variable region (V) is at the tip of each arm of
  the Y
• forms an antigen-binding site

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• Cell-mediated Immunity
• this defense mechanism is produced by T cells
  battles pathogens that have already entered body
  cells
• T cells do not make antibodies - they make
  proteins known as T cell Receptors

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• When a T cell recognizes foreign antigens, they
  differentiate into effector cells
• - cytotoxic T cells kill target cells directly

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receptors on the T cells recognize antigenic
determinants on the target target cell will
then be lysed T cells may also attack cancer
cells prevent them from spreading
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• Helper T cells (many roles)
• - help activate cytotoxic T cells macrophages
• - help stimulate B
• cells to make antibodies
• - interact w/other WBCs that function as
  antigen-presenting cells (APCs) - these cells
  present a foreign antigen to the helper T cell

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Self from Nonself(Blood Types)

• For each blood type there is an antigen present
  on the surface of the RBC
• - Type O has no antigens
• - Type A has antigen A
• - Type B has antigen B
• - Type AB has antigens A B

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• Blood types w/antigens on the surface do not have
  antibodies against that antigen
• another blood group
• antigen is the Rh factor

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- antibodies produced by mom can react
w/blood of fetus - problems when Rh(-) mom
produces antibodies against Rh() fetus
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• Platelets are joined w/fibrinogen
• Fibrin forms
• 3. Clots form

(Our bodies respond to antigens)
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Major Histocompatibility Complex

• Ability to distinguish self from nonself (MHC)
• acts as your biochemical finger-print it is 2
  sets of self proteins on surfaces of our cells
• this complex must be considered before any kind
  of transplant is done

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Immunological Malfunction

• Autoimmune disease - when the immune system turns
  against its own body
• - lupus, rheumatoid arthritis, scleroderma

Lupus,people develop immune reactions against
their own nucleic acids deposits of
antibody-nucleic acid complexes accumulate
causing inflamed joints kidney
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Immunodeficiency diseases cause part or all
of the immune system to be lacking -Hodgkins
Disease is a lymphocyte cancer -Severe
Combined Immunodeficiency (SCID) is when both B
T cells are lacking or inactive (sensitivity
to minor infections)
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• Allergies are overreactions to certain
  environmental antigens
• - these antigens are called allergens (dust,
  pollen, insect toxins, cat saliva)
• - allergic reactions are usually rapid occur
  in nasal passages, skin, bronchi

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-antibodies trigger allergic reactions by
binding to, mast cells noncirculating cells
located in connective tissue
-the antibody mast cell combo binds to an
antigen
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Mast cells Basophils T
lymphocytes Neutrophils Eosinophils

Histamine Tryptase Prostoglandins
Leukotrienes Cytokines
Chemokines
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mast cells release histamine (causes sneezing,
itchiness of skin, tearing of eyes) this
process is called degranulation an
antihistamine is a drug that interferes w/the
actions of the histamine
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Anaphylactic shock is a dangerous type of
allergic reaction -extremely allergic to things
like bee stings, mosquitoes,etc. -blood vessel
will dilate abruptly, causing a drop in blood
pressure (shock)
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What do you know about AIDS?

• When was it first diagnosed in the
• U.S.?
• 2. What do AIDS patients die from?
• 3. What is HIV?

1981
Secondary infections,Ex- Pneumonia, cancer, etc.
Human Immunodeficiency Virus
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4. What does the acronym AIDS stand for? 5.
When does HIV become AIDS?
Acquired Immuno- Deficiency
Syndrome
When the body is no longer able to fight off
infections that a normal immune system could
defend against.
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6. True or False Blood transfusion patients
are at high risk of acquiring HIV. 7. Who is
predominantly diagnosed with AIDS?
FALSE
Anyone having promiscuous sex is at risk. IV
needles with drug use.
(HIV virus)
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8. Which countries are at high risk for
AIDS? 9. True or False The number of new
HIV diagnosed patients in Illinois has
decreased. 10. What is the best way to decrease
or eliminate HIV?
Africa as a whole,and Haiti,
Thailand,poorer, uneducated
FALSE
Dont have sex?
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AIDS

• Acquired Immune Deficiency Syndrome
• since 1981, more than 60 million people worldwide
  have been infected w/the AIDS virus HIV
• since 1981, more than 25 million people worldwide
  have died from AIDS related causes
• 33.4 million people worldwide are living with HIV
• 5 million new cases of HIV were reported in 2004

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Your Area

• New cases of HIV in Illinois
• 2004 1,410
• 2005 1,366
• St. Louis area
• 2003 2,312 HIV
• 4,717 AIDS

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Estimate Range
People living with HIV/AIDS in 2008 33.4 million 31.1-35.8 million
Adults living with HIV/AIDS in 2008 31.3 million 29.2-33.7 million
Women living with HIV/AIDS in 2008 15.7 million 14.2-17.2 million
Children living with HIV/AIDS in 2008 2.1 million 1.2-2.9 million
People newly infected with HIV in 2008 2.7 million 2.4-3.0 million
Children newly infected with HIV in 2008 0.43 million 0.24-0.61 million
AIDS deaths in 2008 2.0 million 1.7-2.4 million
Child AIDS deaths in 2008 0.28 million 0.15-0.41 million
http//www.avert.org/worldstats.htm
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http//www.until.org/statistics
http//www.idph.state.il.us/aids
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• Affects a variety of cells - preferring the
  helper T cells, causing no cell-mediated or
  humoral response
• death usually results, not from AIDS, but another
  infectious agent or cancer