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Session 1a
Transcript of Session 1a
Immunodeficiency Diseases
TrMed 595 Block II - 2011
First Aid organizes
immunodeficiency diseases
by mechanism …..
A different organization ….
Based on how you will see patients
(infants) in Ob/Gyn and Pediatric
clerkships (and USMLE I MCQ’s….)
What is the distinction between humoral-
immunity and cell-mediated immunity?
What is the distinction between humoral- and
cell-mediated immunity?
– Humoral immunity is mediated by circulating Ab –
against extracellularly replicating bacteria.
– Cell-mediated immunity is mediated by T cells
against intracellularly replicating bacteria,
viruses, and fungi.
Why is this important?
Immunodeficiency Diseases (USMLE I MCQ’s found as of 4/20/11)
-Recurrent pyogenic infections:
-Bruton’s agammaglobulinemia (3)
-Hyper-IgM syndrome (1)
-Selective IgA deficiency (3)
-Complement deficiencies (3)
-Common Variable Immunodeficiency (0)
-Leukocyte Adhesion Deficiency (1)
-Immobile Cilia Syndrome (1)
-Chediak-Higashi Disease (2)
-Recurrent fungal and viral infections:
-DiGeorge Syndrome (2)
-IL-12 Receptor Deficiency (1)
-Chronic Granulomatous Disease (2)
-Chronic Mucocutaneous Candidiasis (0)
-Recurrent pyogenic and fungal/viral infections:
-Severe Combined Immunodeficiency (3)
-Other
-Hyper-IgE syndrome (Job Syndrome) (1)
-Wiscott-Aldrich Syndrome (2)
-Ataxia telangiectasia (1)
What JABSOM PBL cases involve humoral
immunity?
What PBL cases involve humoral immunity?
-Streptococcus pyogenes (Ese Saipaia)
-Staphylococcus aureus (Jordu Flaisek, Anna White, etc.
-Hemophilus influenzae (Bob Coffman)
-agent of pyelonephritis (Lina Flaisek)
-agent of vesicoureter reflux (Mara Flaisek)
-Helicobacter pylorii (Melanie Huang)
What PBL cases involve cellular immunity?
What PBL cases involve cellular immunity?
-Mycobacterium tuberculosis (R. Domalagang)
-HIV, Pneumocystis jiroveci (Charles Wilms)
-HIV, Candida albicans (Darlene Walker)
-Rotavirus (Jajo Ebon)
-Hepatitis C (Frank Machado)
-Hepatitis B (Juan Dela Cruz)
Generalization
• Humoral immunity is invoked whenever
extracellular replicating pathogens are
involved. These usually are bacteria….
• Cell-mediated immunity is invoked whenever
intracellular replicating pathogens are
involved. These are viruses, fungi, and some
bacteria
Understanding Humoral vs Cell-
mediated Immunity - Passive
Transfer Mouse Experiments
Passive Transfer Experiments
• Do the following…
– Infect or immunize (vaccinate) mouse A
– After immunity develops, remove either serum (humoral Ab) or spleen (lymphocytes)
– Transfer into naïve mouse
– Challenge with live pathogen…. wait and see
-If serum protects the naïve mouse, humoralimmunity is protective!
-If spleen cells protect the naïve mouse, cell-mediated immunity is protective!
S. pyogenes? Ab or cells protective?
S. aureus? Ab or cells protective?
Hepatitis B? Ab or cells protective?
(Tricky…)
Hepatitis B (Juan Dela Cruz)
• The hepatitis B vaccine is a recombinant S
antigen mass produced in yeast.
• Vaccination will induce humoral antibodies
which will “neutralize” hepatitis B virus upon
infection.
• But…
Ab can neutralize viral infectivity!
Hepatitis B
• The hepatitis B vaccine is a recombinant S
antigen mass produced in yeast.
• Vaccination will induce humoral antibodies
which will “neutralize” hepatitis B virus upon
infection.
• But once the virus enters and begins
replicating within hepatocytes, cell-mediated
immunity is necessary to eradicate the virus!
Humoral Immunity
Opsonization, Neutralization
Opsonization, Neutralization
2) Ab will opsonize S. pyogenes, S. aureus, and H.
influenzae and initiate phagocytosis by PMN’s.
Ab will “neutralize” bacterial toxins, e.g. S. pyogenes
streptolysin O or S. aureus leukocidin,
Ab opsonization of bacterium ….
Initiation of phagocytosis by PMN’s (acute
inflammation)
Ab can also neutralize viruses
(block infectivity)!
Ab will “neutralize” bacterial toxins, e.g. S. pyogenes
streptolysin O or S. aureus leukocidin,
Ab will “neutralize” bacterial toxins, e.g. S. pyogenes
streptolysin O or S. aureus leukocidin,
MCQ’s
World 1. A 7-yr-old male injures his leg while
playing in the yard. He has no significant PMH and
all of his vaccinations are up-to-date. Several days
after the injury, anaerobic cultures of a wound
aspirate grow Clostridium tetani. The patient never
develops tetanus because which of the following?
A) Sensitized CD8+ lymphocytes capable of killing the bacteria
B) Activated macrophages capable of killing the bacteria
C) Neutrophil infiltration of the wound with lysozomalenzyme release
D) Circulating antibodies that activate complement
E) Circulating antibodies that neutralize bacterial products
World 1. An outbreak of influenza A infection is
reported in a small community with 70% of the adult
population remaining uninfected despite prolonged
and repeated exposure to ill contacts. Which of the
following is the most important host factor in
preventing influenza infection?
A) T-cell response against nucleocapsid proteins
B) T-cell response against neuraminidase
C) Circulating antibodies against RNA polymerase
D) Circulating antibodies against hemagglutinin
E) Antigen-nonspecific macrophage response
World 1. A 71-yr-old male who suffers from chronic
obstructive pulmonary disease receives yearly shots
of a killed viral vaccine. When he is subsequently
exposed to this virus, which of the following is
thought to happen?
A) Infective does of the virus is decreased
B) Virus entry into cells in impaired
C) Virus replication inside cells is impaired
D) Viral progeny release from cells is impaired
E) Infected cells are destroyed by sensitized T-
lymphocytes
World 1. A 23-yr-old immigrant gives birth to a
term newborn at home. The infant’s father cuts the
umbilical cord with a kitchen knife. One week later,
the infant develops rigidity and spasms. This child’s
condition could most likely have been prevented by
which of the following
A) Infant vaccination at the time of birth
B) Maternal vaccine during pregnancy
C) Multivitamins during pregnancy
D) Peripartum antibiotics to the mother
E) Proper infant nutrition after birth
End