Transcript The Pearls: Epi 201

BY:
MILANA BERNASEK RN
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Know at least three components of the
immune system
Describe at least two cells in the immune
system and how they respond to infectious
agents
Identify factors that influence the immune
response to infectious agents
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The spleen-A staging ground and place
where immune system cells confront foreign
microbes.
The Lymphatic System-(1)Lymphatic vessels
form a circulatory system that operated in
close partnership with blood circulation. (2)
carries lymph, a fluid that contains WBC’s
(chiefly lymphocytes). And (3) lymph nodes
provide “meeting grounds”.
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Arise in bone marrow
Myeloid progenitor cells develop into cells
that respond early and nonspecifically to
infection
Lymphoid progenitor cells develop into
lymphocytes
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Mononuclear WBC’s produced in bone
marrow
Two major classes:
B cells (mature in bone marrow, produce
antibodies and part of antibody-mediated
immunity.
T cells(mature in Thymus, coordinate entire
immune response and eliminate viruses
hiding in infected cells, Attack and destroy,
Responsible for cell mediated (cellular)
immunity.
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Substance, molecule, or agent (such as
bacterium or virus) that triggers an immune
response
Recognized by immune system as foreign
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Produced to target a specific antigen
When they combine with antigens, can
activate a cascade of proteins (complement)
Complement works with antibodies to destroy
foreign invaders
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Physical/mechanical barriers
Innate immune system
Adaptive (acquired) immune system
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Skin-first line defense
Flushing-tears, saliva, micturation, peristalsis
Acid contents of stomach; bile salts
Cilia action of lung and cough reflex
Mucous membranes
Inflammatory response and phagocytosis (see
the video of phagocyte engulfing Aspergillus
& Candid conidia:
http://en.wikipedia.org/wiki/file:s1Polymorphonuclearcellswithconidiainliquidme
dia.ogg.
Fever
1.
2.
3.
Vascular phase
Cellular phase
Healing phase
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Mechanical response
Pathogenic organisms survive best at normal
body temperature
Immune system can kill pathogens by slightly
raising body’s temperature
Negative aspect
◦ Release of cytokines that produce harmful effects
Cellular barriers
◦ Leukocytes involved
◦ Do not confer long lasting immunity
◦ Identify and eliminate pathogens
Complement
 Complex linear protein molecule
 Called an “effector” molecule
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Leukocytes (WBC’s)
Neutrophils
Phagocytes
Basophiles
Eosinophils
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Humoral
Cell mediated
Lymphocytes involved
Two types
Macrophage attracted to/ingests foreign
antigen
 Antigenic proteins cleaved: fragments appear
on surface of macrophage
 T cell sees macrophage with antigenic protein
on surface and stimulates B cell
 Stimulated B cell divides and makes plasma
cells; plasma cells make antibodies
Note: takes approx. 3 weeks after exposure for
detectable antibodies to appear in the blood
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IgM-current disease; first at site of initial
exposure
IgG-first with subsequent exposure
IgA-secreted on mucous membranes
IgE-allergic reactions
IgD-short-lived; cord blood
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Note: A mnemonic to remember:
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◦ IgM=I’ve got it and I’m making it
◦ IgG=I got it and it’s Gone
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Genetic deficiencies
Drugs
Cancer
Viral infections
Malnutrition
Stress
Iatrogenic factors
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The immune system is a complex network of
cells, tissues and organs that work together
to defend the body against attacks by
“foreign” invaders
When the immune system hits the wrong
target or is crippled, it can unleash a torrent
of diseases, including allergy, arthritis and
AIDS
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EPI 201
◦ Craig CG. Microbial Pathogenicity and Host
Response In: Chapter 14, APIC text of Infection
Control and Epidemiology, 3rd ed.
◦ http://www.cancer.gov/cancertopics/understandin
gcancer/immunesystem (National Cancer Institute.
The Immune System
◦ http://www.nlaid.nih.gov/topics/immunesystem/pa
ges/default.aspx (National Institute of Allergy and
Infectious diseases. The Immune System)