Immunobiology

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Immunobiology
Dr. Ronald Smeltz rbsmeltz_at_vcu.edu
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MICR 505

• Course Director Dr. Daniel Conrad
• dconrad_at_vcu.edu
• Required textbook Immunobiology The Immune
  System in Health Disease 7th ed by Janeway et
  al.

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MICR 505 course guidelines

• Website for course is http//www.courses.vcu.edu/m
  icr505/
• Syllabi as pdf files are on website as well as
  the lecture schedule. Powerpoint files for
  lectures are on the site and any outside reading
  unless told otherwise. Syllabi pdf and ppt files
  can be updated up to lecture time, so check
  (refresh) frequently.
• Syllabi pdf, ppts and outside reading are under
  lecture notes heading.
• Assigned Readings from textbook are listed on
  individual syllabi.

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MICR 505 course guidelines
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Course guidelines

• Check website often for announcements updates
• Four non-cumulative exams. Exam schedule is on
  website.
• Exams have a three-hour time limit. Exam style
  is essay One question per lecture with
  (usually) 10 questions of which the two lowest
  scores will be dropped.
• Last year's four exams are on website under
  exams Use these as study guides.

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The Mona Lisa of Immunology
(III_7_1_T cell development movie)
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Functions of Immune System

• Elimination of anything that is non-self (ie.
  foreign) from the body
• Pathogens, tissue/organ transplants
• Concept of self/non-self discrimination (central
  tolerance)
• Limiting harm caused by non-self which may not be
  eliminated from the body
• Opportunistic pathogens
• Surveillance and removal of abnormal self
• Tumors
• Wound healing
• Bruises, cuts, bites burns

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General Concepts

• Immunity is the ability to resist infection
• Antigen is any substance capable of causing an
  immune response.
• Immune system normally responds to non-self
  antigens, but maintains tolerance to self
  antigens.
• All types of immunity participate in destroying
  or eliminating antigen from body.
• Immune responses are not always beneficial and
  can cause tissue damage or death (breakdown in
  tolerance)
• There are temporal, quantitative, and qualitative
  aspects to immunity

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Temporal aspects of immunity
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Quantitiative aspects of immunity
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Qualitative aspects of immunity
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Immunization leads to immunity

• Immunization- deliberate induction of an adaptive
  immune response
• Passive - Transfer of specific immunity from
  immunized person to non-immune person
• Transfer of serum (ie. antibody) or cells
• Immediate but short-term protection
• Mainly used in life-threatening situations
  (anti-venom)
• Natural form Maternal antibodies in newborns
• Active - Normal development of acquired immunity
  in the non-immune host- requires introduction of
  antigen
• Delayed onset long-term protection
• Basis for vaccinations

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The pathogenic challenges we face
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How do pathogens get in?
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Lymphoid tissues of the immune system
Know your node!
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Lymphoid tissues of the immune system
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Cells of the immune system
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Cooperation between cells results in an effective
immune response

• Cell-cell contact
• Adhesion molecules
• 2. Cytokines
• Chemokines

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Cells of the immune system must traffic and enter
non-lymphoid tissues and organs
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Cell migration into tissues
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Overview Bringing together pathogens and the
immune system
(IV_10_1_The Immune Response movie)
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Innate or Natural Immunity

• Defense mechanisms existing before antigen
  exposure
• Rapid onset
• Does not distinguish among antigens
• Not antigen specific
• No enhanced response on second antigen exposure
• No memory!
• Promotes initiation of acquired responses
• Antigen presenting cells (APC)
• Physical/mechanical/chemical barriers,
  inflammation, natural killer (NK) cells

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Inflammation
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Acquired or Adaptive Immunity

• Defense mechanisms stimulated or induced by
  antigen exposure
• Delayed onset
• Distinguishes among antigens
• Antigen specific
• Enhanced responses upon re-exposure to antigen
• Memory!
• May enhance innate immune responses
• Lymphocytes antibodies

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Antigen transported to lymph node where acquired
response starts
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Types of acquired/adaptive immunity

• Humoral - Major component in plasma or serum of
  blood
• Proteins called antibodies are specific for
  antigen
• Function to eliminate antigens
• Important for extracellular pathogens
• Cell-Mediated - Major component lymphocytes
  specific for antigen
• Kill infected cells produce cytokines
• Cannot be adoptively transferred with serum
• Important for intracellular pathogens

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Acquired/adaptive immunity driven by T cell
subsets
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Characteristics of acquired/adaptive immunity

• Exquisite Specificity - Due to variable regions
  of antigen receptors expressed by B T cells
• Huge Diversity - Due to huge number of different
  antigen receptors of B T cells
• Regulation - Immune responses are self-limiting
  and stop
• Distinguishes Self vs. Non-Self - Tolerance to
  self antigens
• Memory - Enhanced immune response on second
  exposure to antigen

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Immune responses are not always beneficial
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Vaccination

• Concept Immune response can be specifically
  manipulated, so the memory adaptive response will
  prevent a specific infectious disease.
• Name comes from Vaccinia the virus family that
  causes smallpox.
• Countless lives have been saved as a result of
  vaccination.

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Most important Medical Advance of votes

• 15.8
• 14.5
• 13.9
• 11.9

• Sanitation clean water/sewage disposal
• Antibiotics
• Anesthesia
• Vaccines

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On May 14, 1796, Sarah Nelmes, a milkmaid, came
to Jenner with cowpox. He devised a brave and
dangerous experiment. He passed on the cowpox
disease to James Phipps, his gardener's son, by
scratching the boy's skin with infected metal
(vaccination). When James recovered from cowpox,
Jenner tried to give him smallpox. James failed
to contract the smallpox disease.
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Clonal selection the foundation for adaptive
immunity
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Clonal selection the foundation for adaptive
immunity
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Clonal selection the foundation for adaptive
immunity
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