Transcript Unit 8 Seminar

Microbiology
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Neutrophils: Phagocytic
Basophils: Produce histamine
Eosinophils: Toxic to parasites, some
phagocytosis
Dendritic cells: Initiate adaptive
immune response, phagocytic
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Monocytes: Phagocytic as mature
macrophages
Fixed macrophages in lungs, liver,
bronchi
Wandering macrophages roam
tissues
Lymphocytes: Involved in specific
immunity
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pseudopods
of
macrophage
entrap E.coli
bacteria
bacteria
brought into
macrophage
for
destruction
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Serum proteins activated in a cascade.
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Activated via one of three pathways
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Activated Complement proteins trigger a
number of immune responses
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Opsonization
Cytolysismembrane
attack
complex
Inflammation
Figure 16.10
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The complement system is
an important part of the
innate immune system that
has far-reaching effects on
the body’s ability to fight off
infection. Many pathogens
have the ability to affect or
disable individual proteins
within the Complement
system. In your opinion,
which Complement protein
(C5a? C1?) would be most
devastating to the host
immune system if it were to
be inactivated by a
particular pathogen? Why?
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Bone marrow gives
rise to B cells.
B cells have surface
antibodies (Igs) that
recognize epitopes
T-dependent
T-independent
Figure 17.9
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Specialized lymphocytes, mostly T cells, respond
to intracellular Ags
After differentiating in the thymus, T cells
migrate to lymphoid tissue
T cells differentiate into effector T cells when
stimulated by an Ag
Some effector T cells become memory cells
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Helper T Cells (CD4, TH)
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TH1
TH2
IgE
Activate cells related to cell-mediated immunity
Activate B cells to produce eosinophils, IgM, and
Cytotoxic T Cells (CD8, TC)
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Destroy target cells with perforin
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As you have learned in this unit, the immune
system does an exceptional job in clearing
infections from the host. However, on occasion the
immune system can actually make an illness worse
by overreacting to a potential pathogen. One
example is a phenomenon called “cytokine storm”.
This occurrence takes place when the body is
infected by specific pathogens. Some examples
include the influenza virus that caused the 1918
Spanish Flu epidemic and more recently the SARS
epidemic in 2003. What occurs during “cytokine
storm” and how does it affect the host? Find an
example of a more recent disease (hint: look at the
flu virus) that induces cytokine storm.
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“Acute respiratory viral infection (especially
from the H5N1 subtype influenza virus) results
in a cytokine storm effecting the lungs, and
subsequent damage to alveoli and lung tissue
results in the lethality seen in more severe flu
viral infections, especially those fatalities
among young healthy adults”
http://www.cytokinestorm.com/ accessed July 21, 2011
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Human society has evolved significantly over the past
few decades. Populations of humans used to inhabit
wide-open spaces and rarely had contact with large
crowds of people. However, modern society requires
people to live in very tight quarters and come into
contact with possibly hundreds or thousands of people
in a single day. Consider cities like New York City and
Tokyo, Japan. Occupants in these cities are packed in
tightly into subway systems and overcrowded
conditions. When people in Japan are ill, they wear face
masks to protect others, while in New York City this is
not done. What are some other ways that people in
these cities (and other large cities around the world)
deal with potential exposure to pathogens?
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Microbiology encompasses many aspects of pathogens and
human reactions to infections. This project will allow you to trace
pathogens through the infection cycle and human response to the
infection.
Project requirements: Refer to Table 1.1 and answer the following
questions for EACH organism listed above. Word requirements
are outlined for each question - this represents a minimum number
of words required. For each question answer in full and complete
sentences, and provide both examples and scientific evidence to
support your answer. Be sure to include a well-developed
introduction and conclusion in your paper.
You may use outside sources, but the reading material for Units 7
and 8 should provide the majority of information you will need to
complete the assignment. Be sure to include all references in APA
format.
Organism
Strategy to avoid host
immune system
Common disease
Trypanosoma cruzi
Changes surface
antigens to avoid
immune system
detection
American
trypanosomiasis
Human
immunodeficiency virus
(HIV)
Virus infects and hides
in macrophages and
CD4 T-cells.
Acquired
immunodeficiency
syndrome (AIDS)
Streptococcus
pneumoniae
Produce M proteins to
inhibit phagocytes from
attaching
Pneumonia
1. Give a brief overview of the disease including signs and symptoms. Who is
typically affected by this infection?(Children? Immunocompromised
patients?)? What is the pathogens’ portal of entry and exit? (100 word
minimum)
2. How would the innate immune system react to this pathogen? Which
components would react? (75 word minimum)
3. Would this pathogen primarily stimulate cell-mediated immunity or
antibody-mediated immunity (T cells or B cells?) Why? (75 word
minimum)
4. All of the organisms listed above have the ability to evade the host immune
system, at least temporarily. Review Table 1.1 for the pathogens’
strategies used to avoid the host’s immune system. Why is this particular
strategy helpful to the pathogen? How would this impact the pathogens’
ability to cause infection? How would the immune system compensate?
(200 word minimum)
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Tortora, G., Funke, B., & Case, C. (2007).
Microbiology: An Introduction (8th ed.). San
Francisco, CA: Pearson.