Download 1) The virion of the following viruses contains a polymerase EXCEPT:

IMMUNOLOGY:
1)
T-cell activation involves:
A
B
C
D
2)
Natural Killer cell are
A
B
C
D
3)
be destroyed
induce a graft-versus-host reaction in the recipient
survive and induce tolerance to strain A grafts in the recipient
survive without any effects on the recipient
Antigen-presenting cells that activate helper T-cells must express which
one of the following on their surface?
A
B
C
D
E
6)
The hapten be recognized by helper T-cells
The hapten be recognized by suppressor T-cells
The protein be recognized by B-cells
The protein be recognized by helper T-cells
Two dissimilar inbred strains of mice, A and B, are crossed to yield an F1
hybrid strain. If a large dose of spleen cells from an adult A mouse is
injected into an adult AB mouse, which of the following is MOST likely to
occur? The spleen cells will
A
B
C
D
5)
Able to kill virus-infected cells without prior sensitization
B-cells
Cytotoxic T-cells
Increased by immunization
In the immune response to a hapten-protein conjugate, in order to get antihapten antibodies it is essential that
A
B
C
D
4)
Autocrine and paracrine cytokines
Conformational changes in the CD3 peptide chains.
Docking of tyrosine kinases to extracellular domains of the CD3
peptide chains
Irreversible increases in intracellular Ca2+
Class I MHC
Class II MHC
CD4
IgM
Thy-1
The role of macrophages during an antibody response is to
A
Express Fc receptors
B
Lyse virally infected cells
C
Process and present antigen
1
D
Suppress cytotoxic T-cells
MICROBIOLOGY: VIROLOGY
1) The virion of the following viruses contains a polymerase EXCEPT:
A
B
C
D
Hepatitis B virus
Human Immunodeficiency virus
Influenza virus
Togavirus
2) All of the following statements about negative-stranded RNA viruses are true,
EXCEPT:
A
D
All of them have helical capsids
B
They are all enveloped viruses
C
They are genetically related and likely have a common ancestor
They replicate exclusively in the cytoplasm
3) Rhinovriuses are causative agents of the common cold. No vaccine is available
against these infections, because:
A
B
C
D
It has been difficult to attenuate the virus in the laboratory for vaccine
preparations
It mutates rapidly
Human rhinoviruses combine with animal strains so that new antigenic
types continually emerge
There are too many serotypes, which makes vaccination impractical
4) Respiratory syncytial virus is an important respiratory pathogen. All of the
following statements are true, EXCEPT:
A
B
C
D
Because it is a DNA virus there is no effective antiviral agent available to
treat this infection
It is the most common cause of lower respiratory infections in infants and
causes approximately 90000 hospitalization per year
It occurs in yearly outbreaks
Unlike with some of the common childhood viral infections, life-long
immunity does not occur and re-infections may occur throughout life.
5) The following statements about interferons are true, EXCEPT:
A
Interferons can bind to and inactivate viruses directly
B Interferons can modulate immunity
C Interferons posses anti-tumor activity
2
D Interferons suppress both viral and cellular mRNA translation
6) Acyclovir is used against HSV and VZV infections because:
A
B
C
It can effectively eliminate latency established by HSV and VZV
It is efficiently converted to the active monophosphate form by the cellular
thymidine kinase in HSV and VZV infected cells
It reduces the duration of virus shedding and the frequency of recurrences
7) All of the following statements about polyomaviruses are true, EXCEPT:
A
They are able to establish a latent infection in humans
B They have circular double stranded DNA
C They have an envelope
D The T-antigen is an important structural protein
8) All of the following statements about papillomaviruses are true, EXCEPT:
A
B
C
D
They infect epithelial cells
They have been associated with cervical dysplasia
The virion contains a single stranded DNA molecule
More than 80 serotypes have been identified
9) Because retroviruses have genomes composed of RNA (hence the name RNA
tumor viruses), they would not be affected by drugs that inhibit DNA synthesis:
A True
B False
True (A) or False (B)?
10)
Adenovirus virion contains a single stranded DNA molecule B
11)
Adenovirus replicates in the nucleus of the host cell A
12) Different strains of adenoviruses replicate either in the respiratory
tract or the gut, never in both B
13)
Adenovirus interferes with the interferon response A
14)
B19 uses its own polymerase for replication
B
15)
B19 can be transmitted through the placenta A
16)
B19 infects mature and progenitor erythroid cells B
17) A major reason for the high incidence of herpes simplex
virus infections in the U.S. population is that the virus:
3
A
B
C
D
E
Has a very short incubation period, which facilitates rapid spread.
Mutates frequently and escapes immune surveillance.
Prevents the production of antibodies in the infected host
Remains highly infective for many days on objects or surfaces touched by
infected individuals.
Sheds from infected individuals even when they are asymptomatic
18) Erythema infectiosum (Fifth disease), a self-limiting disease of children, is
caused by:
A
B
C
D
E
F
Human Herpesvirus 3
Human Herpesvirus 6
Measles virus
Parvovirus
Rubellavirus
Variolavirus
19) Which of the following statements is NOT true about
adults, who have herpes simplex infections: They
A
B
C
D
E
Carry the virus in a latent state
Develop circulating antibodies to the virus
Develop permanent immunity that prevents recurrent infections
May shed virus for long periods
Usually acquire the infection in childhood
FOR QUESTION 20 AND 21:
20) A two-week-old infant was admitted for a two-day history of fever and irritability.
He was born to a 20-year-old mother with no prior pregnancies but a gestation
complicated by a painful vaginal infection in the sixth month, treated with an
unknown oral medicine. On physical examination, the infant was found to have
small red vesicular and pustular lesions on the scalp, was irritable and running a
fever of 102.5°F. The mother had been immunized as a child against measles,
mumps and rubella, but her antibody titer to these viruses were unknown. She had
chicken pox as a child.
Based on this information, the most likely cause of the infant’s illness is which of the
following:
A
B
C
D
Congenital Cytomegalovrus infection
Congenital Herpes Simplex infection
Congenital Rubellavirus infection
Congenital Varicellavirus infection
4
21) Which of the following courses of management should be followed?
A
B
C
D
Culture fluid from the scalp lesions, blood and CSF for viruses. Await
the result before starting treatment
Culture fluid from the scalp lesions and the CSF for Herpes simplex and
begin acyclovir treatment immediately
Culture fluid from the scalp lesions and the CSF for Herpes simplex and
begin ribavirin treatment immediately
Measure serum antibody titers to Herpes simplex, Varicella-zostervirus
and Cytomegalovirus in both the mother and the infant to establish the
diagnosis. Await the result before starting treatment.
FOR QUESTIONS 22 AND 23:
22) An 18-year-old Caucasian male presented with a one-week history of low-grade fever,
fatigue, abdominal pain and vomiting. A day prior to presentation he became
jaundiced. There was no history of exposure to hepatitis, but he was sexually
active and reported IV drug use within the prior 6 months. His bilirubin and liver
enzymes were elevated, suggesting inflammation of the liver. Hepatitis B surface
antigen (HbsAg) test was positive and tests for the other forms of viral hepatitis
were negative.
What instruction regarding infectivity of this patient is correct?
A
B
C
D
A Hepatitis B e-antigen (HbeAg) test should be done and if negative he
should be considered non-infectious.
He is most likely a chronically infected by Hepatitis B virus and should be
considered non-infectious as soon as the bilirubin and liver enzyme values
have normalized
His illness is most likely due to Hepatitis B virus and he should be
considered infectious (through blood and sexual contact) until HBsAg
becomes negative and Hepatitis B surface antibody (anti-Hbs) becomes
positive
To avoid fecal-oral transmission to other individuals he should not be
allowed to prepare food for others
23) Which of the following statements regarding the above patient are TRUE?
A
B
C
D
Antibody to hepatitis B core antigen (antiHBc antibody) will become
positive several months after recovery from hepatitis B
The most likely outcome of his infection is cancer of the liver
The surest way of preventing his infection would have for him to have been
vaccinated against Hepatitis B as a child
Since he acquired Hepatitis B as an adult he has a 90% risk of becoming
chronically infected
5
24) Which of the following viruses are often associated with congenital infections of
newborns, which damage the developing fetus during pregnancy ?
i
ii
iii
iv
v
vi
vii
Cytomegalovirus
Human immunodeficiency virus
Measlesvirus
Mumpsvirus
Rubellavirus
Parvovirus
Varicella zostervirus
A
B
C
D
i, ii, iv, v, vi, vii
i, ii, v, vi, vii
i, ii, v, vi,
i, v, vi
25)
A
B
C
D
E
26)
Which of the following viral infections is commonly transmitted by small droplet
aerosol and is the most contagious of them all?
CMV
B19
Hepatitis B virus
Rubella
Variola
Which of the following properties made smallpox eradicable?
A
B
C
D
Monkeys are a reservoir
no carrier state
no inapparent infection
only one antigenic viral strain exists
MICROBIOLOGY: DIAGNOSTIC MICROBIOLOGY
1) Which of he following steps may be involved when attempting to identify a
pathogen in a specimen?
A
Differentiation between endogenous and pathogenic organisms
B
Selection against endogenous organisms
C
Both
D
Neither
2) If you were to develop an Enzyme-Linked-Immunosorbent-Assay (ELISA) to detect the
presence of growth hormone, would you absorb antigen or antibody to the ELISA
plate (solid phase)?
A
B
Antibody
Antigen
6
3) Why is a change in antibody titer considered significant only when it is fourfold or
larger?
A
B
C
D
the intrinsic error of the ELISA is two
the intrinsic error of the ELISA is four
twofold differences occur frequently due to the high intrinsic
background of serum
within any given individual the daily fluctuations of antibody titers
are twofold
MICROBIOLOGY: GENERAL MICROBIOLOGY:
1)
The most efficient skin disinfection for a surgical patients is application of:
A
B
C
D
2)
alcohol
detergent and soaps
germicidal lamp exposure
iodophor compounds
Which one of the following statements is NOT true?
A In Europe and the US death due to infection is increasing
B Infectious diseases are spread by five basic methods: food, fomite
spread, respiratory transmission, sexual transmission, vector borne,
zoonotic and vertical.
C Knowledge of the pathogen and pharmacology is usually sufficient
to initiate effective treatment
D Most people worldwide die of an infectious disease
3)
Which one of the following statements is NOT true?
A A special group of toxins, usually related to the bacterial cell wall
are called endotoxins
B HIV and malaria evade the host’s immune system by frequently
changing their surface antigens
C The human host’s first line of defense against infections are
antibodies and cytotoxic killer cells
D To cause disease an infectious apthogen must be presented to the
host in a way and in an environment that will allow it to grow
E Virulence factors are mechanisms employed by a pathogen to
establish itself and produce disease
4)
Which one of the following statements is NOT true?
A Eighty percent of diagnoses are made from just the history and the
physical exam
B It is very common for people, who have an infection, not to show
any identifiable symptoms and yet become immune
7
C Most people die of infectious diseases, which are not preventable
D The incubation period is the time it takes for the pathogen to
establish itself to the point where the first symptoms appear
E The same infectious disease agent can cause a variety of different
clinical syndromes
MICROBIOLOGY: BACTERIOLOGY: GRAM(+)COCCI:
1) A 2250 gram male infant was born to a 23-year-old woman. Pregnancy was
uneventful. At 52 hours of age, the infant developed a generalized convulsion.
Cultures of blood and CSF yielded b-hemolytic organisms. Which one of the
following characteristics is consistent with this organism?
A
B
C
D
Positive CAMP test
Positive Catalase
Pyrrolidonyl arylamidase (PYRase) positive
Susceptible to optochin
2) A 6-year-old boy presented with a 1-week history of fever, sore throat and
headache. One day before hospital admission, he awakened with pain and swelling
in the right ankle. In addition to a warm, swollen right ankle, he was noted to have
a new grade II/IV systolic heart murmur thought to be consistent with mitral
regurgitaion. He was admitted to the hospital with a presumptive diagnosis of
acute rheumatic fever. Which one of the following is consistent with this organism?
A
B
C
D
CAMP test positive
Produces alpha hemolysis on sheep blood agar plates
Pyrrolidonyl arylamide (PYRase) positive
Resistant to bacitracin
3) A 7-year-old girl was admitted with a 3-day history of increasing pain and swelling
of her left leg. The patient recalled some trauma to her left leg. The patient was
febrile (temperature of 39.2oC), left leg was red, swollen, warm and very tender.
Bone scan and CT revealed subperiosteal abscess. Cultures of blood and abscess
grew gram positive organisms. Which one of the following characteristics is
consistent with this organisms?
A
B
C
D
Able to grow in bile and in 6.5% salt
Almost all strains produce coagulase
Catalase negative cocci in clusters
Resistance to nacomycimn is common
MICROBIOLOGY:BACTERIOLOGY:GRAM (-)BACILLI:
1) Enteroinvasive E.coli has the following properties EXCEPT:
A
Causes bloody, mucous diarrhea
B
Chromosomal sequences related Shigella
8
C
D
E
Destroys the intestinal mucosa
Does not require antibiotic treatment
Produces Shiga toxin
2) Salmonella thyphi causes disease by
A Forming a thick capsule
B Releasing endotoxin
C Resisting phagocytosis
D Producing an exotoxin
3) Salmonella typhi and Salmonella enteritis share the following properties
EXCEPT:
A
B
C
D
Spread systemically
Invade the epithelial cells of the intestine
Are food borne pathogens
Possess endotoxin
4) Legionella pneumophila is characterized by the following statements:
A Air conditioning units are often the source of the pathogen
B It is diagnosed in HE stained sputum specimen
C Requires X and V factor to grow in culture
MICROBIOLOGY: BACTERIOLOGY:GRAM(+)BACILLI:
FOR QUESTION 1 AND 2:
A 2 year-old child was brought to the ER with an upper respiratory infection. The
patient was febrile to 38.9oC and had an exudate in the posterior pharynx that was
described as a yellowish membrane, which bled when scraped and removed. The
patient’s medical history revealed that he had not received any immunizations.
1)
The patient was admitted. Special cultures were requested for the suspected
pathogen. What was the suspected pathogen?
A
B
C
D
E
2)
Bordetella pertussis
Corynebacterium diphteriae
Haemophilus influenzae
Streptococcus pyogenes
Epstein Barr Virus
How does this organism cause disease?
A
B
C
D
E
Causes disseminated intravascular coagulation
Causes Toxic Shock syndrome
Spreads to the CNS, where it causes meningitis
Produces toxins that interfere with protein translation
Produces toxins that increase cellular cAMP level
9
3)
The patient is a neonate born at 32 weeks of gestation. The baby was intubated
at birth because of poor respiratory effort. Blood and CSF specimens taken from
the infant grew small, aerobic, gram positive rods. On the basis of the patient’s
age and the description of the organism, what organism is likely?
A
B
C
D
Bacillus cereus
Clostridium perfringens
Gardnerella spp
Listeria monocytogenes
For question #4,5 and 6:
A 64-year-old man presented to the clinic with an abscess in his mouth. He
stated that the abscess had been getting larger for a period of three months. He
was homeless and had not sought medical care until this presentation. A sinus
track had formed from the abscess to the outside of the face. An aspirate of the
abscess was sent to the laboratory for gram stain and culture. The culture was
positive for Actimomyces spp.
4)
What was the Gram stain report of this organism?
A
B
C
D
5)
What is the source of this organism?
A
B
C
D
6)
Gram positive, box car cells
Gram positive, branching, thin rods
Gram positive cocci in clusters
Gram negative, intracellular diplococci
Contaminated food
Gastrointestinal flora
Oral flora
Soil
How can this organism be differentiated from Nocardia spp?
A
B
C
D
Actinomyces spp forms target hemolysis on a blood agar plate
Nocardia spp has a capsule
Nocardia spp is acid fast
Nocardia spp produces branching rods
For question #7 and 8:
A 13-week-old baby girl was brought to the Peds ER. The baby was weak,
lethargic, fed poorly and constipated. Baby was hospitalized. After admission, it
was noted that the baby was gradually becoming paralysed. A diagnosis was made
10
when the mother reported that she had sweetened the baby’s formula with
organically grown honey.
7)
What is the most likely diagnosis?
A
B
C
D
8)
Group B streptococcal disease
Infant botulism
Infant poliomyelitis
Listeriosis
How can the diagnosis be confirmed?
A
B
C
D
Culture of baby’s formula
Culture of baby’s stool
Culture of baby’s stool and detection of toxin in baby’s stool
Detection of toxin in baby’s blood
For question #9, 10 and 11:
The patient was a 35-ear-old woman. She worked in a fast food restaurant. She
was brought to the emergency room, weak and somnolent. She had trouble
swallowing. She told the physicians that previously she had been in good
health. Her condition worsened and she developed descending quadraparesis,
requiring intubation. Cultures of her stool and gastric content were negative. A
blood specimen was sent to the laboratory and gave a positive result. She
remained hospitalized for six weeks and then returned to her previous good
health.
9)
What was wrong with this patient?
A
B
C
D
10)
Classical botulism
Classical tetanus
Systemic Clostridium perfringens infection
Enterohemorrhagic E.coli
What test was ordered to confirm the diagnosis?
A Antibody titer
B Blood culture
C Toxin detection
11)
What is the appropriate for this patient?
A Antibiotics
B Hyperbaric pressure treatment
C Maintenance of respiratory function
11
For question #11 and 12:
A 21-year-old male presents with three days of abdominal pain and tenderness in
midgastric and lower abdomen. He was febrile (39.2oC), tachycardic and
tachypneic. He was admitted and blood cultures were sent to the laboratory. On an
exploratory laparotomy, he was found to have a gangrenous and perforated
appendix.
12)
The blood cultures were positive for a Gram neg rod. What is the most likely
organism?
A
B
C
D
13)
Bacteriodes fragilis
Bacillus subtilis
Bacillus cereus
Clostridium perfringens
What is the possible source for this organism?
A
B
C
D
Contaminated food
Gastrointestinal flora
Genital flora
Oral flora
MICROBIOLOGY: BACTERIOLOGY: ACID-FAST BACILLI
1) Which one of the following statements is NOT true?
A
An individual gets infected with TB by inhaling tubercle bacilli
present in small droplets
B
From 1985 through 1992, the number of new TB cases in the United
States increased by 80%
C
Mycobacterium tuberculosis complex includes M. tuberculosis, M.
bovis and M. ulcerans
D
TB is the leading cause of death due to infectious disease in adults
around the world
E
The resurgence in TB cases between 1985 and 1992 can be
attributed to the HIV epidemic, immigration from countries where
TB is common, the spread of TB in correctional facilities and
homeless shelters and inadequate funding for TB control
2) Which one of the following statements is NOT true?
A
AIDS reduces the patient’s immune response to TB so they have
less severe disease
B
Because they are relatively resistant to disinfection, the
Mycobacterium fortuitum complex have caused infections related to
artificial heart valves, hip prostheses and dialysis fluids.
12
C
Isolation from blood or other normally sterile body tissues is
sufficient to make a diagnosis of disseminated non-tuberculosis
mycobacterial disease
D
Mycobacterium avium complex (MAC) is most associated with
disseminated disease in patients with AIDS
E Patients, whose sputum is smear positive for tuberculosis transmit
the disease and should be treated
F
The non-tuberculous mycobacteria are difficult to treat because
they are drug resistant
3) Which one of the following statements is NOT true?
A
About 75% of leprosy patients with an early solitary lesion heal
spontaneously
B
Mycobacterium leprae causes a chronic disease of the superficial
segments of peripheral nerves
C
Mycobacterium leprae is an obligate intracellular parasite, which
multiplies very slowly in mononuclear phagocytes
D
The diagnosis of leprosy is confirmed by growth of Mycobacterium
leprae on culture medium for a period of six weeks
MICROBIOLOGY: PARASITOLOGY
1) What morphological form of the malaria parasite will you most likely see in a
blood smear during a fever episode?
1)
2)
3)
4)
5)
6)
7)
A
B
C
D
Ringform
Young trophozoite
Mature trophozoite
Young schizont
Mature schizont
Mereozoite
None
1 and 5
1, 5 and 6
2, 3 and 4
7
For question #2 and #3:
A young woman from Syria presented with skin lesions on her arm and face. The
lesions were raised papules that were firm but not painful. On the same day, a young
man from Africa presented with hepatosplenomegaly (enlarged liver and spleen),
abdominal pain, fever and pallor. In both cases the cause of their symptoms was
discovered to be a parasitic infection with Leishmania, but b two different species of
this parasite.
13
2) The symptoms of the patient from Africa are consistent with:
A
B
C
D
Disseminated helminth infection
Disseminated protozoan infection
Localized helminth infection
Localized protozoan infection
3) The differences in the symptoms of the two patients was determined in part by a
difference in the species of the parasite; this difference is most likely related to the
following:
A
B
C
D
Host temperature optimum
Invertebrate host
Parasite temperature requirement
Vertebrate host
4) A patient arrived in a rural health clinic in Columbia, South America, with a
distended and painful abdomen and reported that he had not had a bowl
movement in more than six weeks. The patient reported that his home was infested
with vinchuca, also known as the “kissing bug”.
This patient is most likely infected by
A
B
C
D
Leishmania braziliensis
Leishmania donovani
Trypanosoma cruzi
Trypanosoma gambiense
5) A 40-year-old woman presented with a chronic history of vague abdominal
discomfort, hunger pains and indigestion. She was found to have moderate
eosinophilia and was slightly anemic. She reported that she and her husband
frequently dined in gourmet restaurants and greatly enjoyed steak tartare (highly
seasoned raw beef). An ova and parasite examination of the patient’s stool was
positive for proglottids and eggs of Taenia sagginata, the beef tape worm. Taenia
sagginata undergoes sexual reproduction in the human gastrointestinal tract,
therefore, humans are considered to be the
A
B
C
D
Definitive host
Intermediate host
Paratenic host
Sexual host
MICROBIOLOGY: UPPER RESPIRATORY INFECTIONS
1) Which of these conditions occurs because a bacteriophage containing the genetic
information governing toxin production infects the causative organism?
A Diphteric membranous pharyngitis and scarlet fever
B Gonococcal pharyngitis and staphylococcal pharyngitis
14
C Infectious mononucleosis and mumps
D Sore throat without a rash due to Streptococcus pyogenes and
epiglottis due to Haemophilus influenzae
MICROBIOLOGY:
INFECTIONS
LOWER
RESPIRATORY
TRACT
1) In an adult patient with pneumonia, a Gram stain of sputum, which shows >25
polymornuclear leukocytes (PMNs) per Low Power Field (LPF) and <10 epithelial
cells per LPF associated with >8-10 lancet-shaped Gram-positive cocci, suggests
which of the following organisms:
A Haemophilus influenzae
B Klebsiella pneumoniae
C Mycoplasma pneumoniae
D Streptococcus pneumoniae
2) In patients with HIV/AIDS the most important pathogen causing pneumonia is
which of the following:
A Coccidiodes immitis
B Mycoplasma pneumoniae
C Pneumocystis carinii
D Staphylococcus aureus
3) A 65-year-old male presents with a 3 day history of cough productive of green
sputum with right sided chest pain on deep inspiration. He also reports high fever,
rigors and a 5 pound weight loss in the past month. On physical exam he is noted
to have a temperature of 38.5°C, RR 26, BP 120/80, HR=100 regular, poor dentition,
injected pharynx, 0.5cm non-tender lymph nodes in anterior cervical area and
decreased breath sounds at the right base, dullness to percussion at right base and
course bronchi and rales at the right lower lobe. Sputum examination reveals ,10
epithelial cells, >25 WBC/LPF with numerous gram negative bacilli. Lab revealed a
WBC of 13,400 with 60 segs, 14% bands, 30% lymphs and a serum Cr of 1.8. CXR
shows a right lower lobe infiltrate with blunted costrophrenic angle. Based on the
clinical presentation and the Gram stain the most likely diagnosis is:
A
Klebsiella pneumoniae
B
Mycobacterium tuberculosis
C
Mycoplasma pneumoniae
D
Pneumocystis carinii
E
Staphylococcus aureus
F
Streptococcus pneumoniae
4) A 65-year-old female presents with a 3 day history of cough productive of green
sputum with right sided chest pain on deep inspiration. She also reports high
fevers, rigors and a 3 pound weight loss in the past month. Also of note, she had
“the flu” with URI symptoms, sore throat, severe myalgias, fever and cough
(mildly productive) that also “attacked” other friends and family. On physical
exam she is noted to have a temperature of 38.5°C, RR 26, BP 120/80, HR=100
regular, poor dentition, injected pharynx, 0.5cm non-tender lymph nodes in
anterior cervical area and decreased breath sounds at the right base, dullness to
15
percussion at right base and course bronchi and rales at the right lower lobe.
Sputum examination reveals <10 epithelial cells, >25WBC/LPF with numerous
gram positive cocci in clusters. Lab revealed a WBC of 13,400 with 60% segs, 14%
bands and 30% lymphs and serum Cr of 1.8. CXR shows a right lower lobe
infiltrate with blunted costophrenic angle. Based on the clinical presentation and
Gram stain the most likely diagnosis is:
A
Klebsiella pneumoniae
B
Mycobacterium tuberculosis
C
Mycoplasma pneumoniae
D
Pneumocystis carinii
E
Staphylococcus aureus
F Streptococcus pneumoniae
MICROBIOLOGY: CNS INFECTIONS
1) A 55-year-old renal transplant recipient on chronic steroid therapy is hospitalized
with fever and headaches of 5 days duration. On examination, the patient is
confused and has nuchal rigidity. A lumbar puncture disclosed 120 WBC (80%
Lymphocytes), CSF glucose of 40 and CSF protein of 95. A smear of CSF revealed
many WBC but no organisms. The most likely cause is:
A
B
C
D
Herpes simplex meningitis
Listeria meningitis
Neisserial meningitis
Pneumococcal meningitis
MICROBIOLOGY: SYSTEMIC INFECTIONS
1) What are the current most common etiologic agents in the US causing sepsis in
children beyond the neonatal period?
A Haemophilus influenzae and Neisseria meningitides
B Listeria monocytogenes and Herpes simplex
C Neisseria meningitidis and Streptococcus pneumoniae
D Staphylococcus aureus and Streptococcus agalactiae
E Streptococcus agalactiae and E.coli
2) Injecting drugs users are at an increased risk of bloodstream infection due to which
of the following organisms?
A
B
C
D
Brucella melitensis
Rhodotorula rubra
Saccharomyces cerevisiae
Staphylococcus epidermidis
3) A 38-year-old male with a diagnosis of AIDS and Cytomegalovirus retinitis, with
an indwelling IV catheter for receipt of CMV treatment is admitted to the hospital
16
with fevers to 103 °F and shaking chills. Physical exam is normal and there is no
evidence of infection at the catheter insertion site. 24 hours following admission,
the laboratory reports that blood cultures are positive for gram positive cocci in
clusters. What organisms are likely?
A
B
C
D
Enterococcus faecalis
Staphylococccus aureus
Staphylococcus epidermidis
Staphylococcus epidermidis and Staphylococcus aureus
MICROBIOLOGY: GI INFECTIONS
1) Half of the attendees at a student reunion became ill two hours after a luncheon
buffet. The menu included quiche, baked chicken, deviled eggs, potatoe salad,
gelatin salad and egg custard among other fine picnic fare. Those ill, experienced
projectile vomiting, nausea and abdominal pain. Several of the affected individuals
also had diarrhea. If you cultured all of the above menu items, high level of
contamination with which organism is most likely?
A
B
C
D
E
Enterococcus faecalis
Salmonella typhi
Staphylococcus aureus
Staphylococcus epidermidis
Yersinia enterocolitia
Immunology
Practice Exam #2
(1pt each)
Place a T in front of the characteristics unique to T cell epitopes, a B in front of the
characteristics of B cell epitopes or an X in front of characteristics common to both T cell
and B cell epitopes.
1_____epitopes present on antigens present free in solution
2_____epitopes often present within the interior of a polypeptide
3_____epitopes contain hydrophilic amino acids
4_____epitopes are frequently accessible on the exposed surface of an antigen
5_____antigen processing of the epitope is required for recognition
6_____peptides which must be presented in association with MHC molecules
7_____may be a conformational epitope rather than a sequential epitope
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8_____epitopes generally are oligopeptides
(1pt each)
Fill out the below table by using a (+) if yes or a (-) if no
secIgA IgG
IgM
serIgA IgE
IgD
Exists exclusively as a monomer
Multimeric forms have J chain
Multimeric forms have a secretory
component
Can fix complement by the classical
pathway
Can agglutinate particulate antigens
Can cross the human placenta
Heavy chain composed of 4 constant
region domains
Binds to Fc receptors on basophils
and mast cells
Present on the surface of mature,
virgin B cells
Multiple Choice Questions (1 pt each)
18. Which of the following is true of epitopes associated with antigens from an exogenous
source:
a)
b)
c)
d)
presented in association with Class I MHC
presented to T helper lymphocytes
presented to T cytotoxic lymphocytes
associate with MHC molecules within the ER
19. Which of the following mitogens is specific for B
cells?
a)
b)
c)
d)
Con A
PHA
LPS
PWM20.
20. All cases of menstrual toxic shock syndrome appear
to be caused by:
a)
b)
c)
d)
SEA
TSST-1
SPE-A
SEC
21. Toxic shock syndrome and toxic shock-like syndrome are both caused by:
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a)
b)
c)
d)
exotoxins synthesized by Staphylococcus aureus
exotoxins synthesized by Group A Streptococcus
superantigens
autoantibodies
Refer to the figure below which depicts the electrophoretic separation of serum for
questions 22 and 23
22. In which of the fractions would you find immunoglobulins?
a)
b)
c)
d)
23. In which of the fractions would you find serum albumin?
a)
b)
c)
d)
24. Membrane bound Ig is just one part of a complex known as the B cell receptor
complex. Additional accessory proteins are termed:
a)
b)
c)
d)
Iga and Igb
CD4 and CD8
Ca and Cb
CD3 and TcR
25. The above accessory proteins contain long cytoplasmic domains that can be
phosphorylated at which of the following amino acid residues:
a)
b)
c)
d)
serine
tyrosine
proline
asparagine
26. Which of the following types of antigenic determinants of Ig are found within the
variable region domains:
a) isotypic
b) allotypic
c) idiotypic
27. Goat anti-mouse IgG would best be described as:
a) an anti-idiotypic antibody
b) an anti-allotypic antibody
c) an anti-isotypic antibody
28. Subtle amino acid differences within the CL and CH regions of Ig occur due to the fact
that they are encoded by different alleles. Such antigenic determinants are termed:
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a) isotypic
b) allotypic
c) idiotypic
29. Dryer and Bennet are credited with:
a)
b)
c)
d)
discovering multiple myeloma
explaining the structural basis of Ig diversity
proving that Ig genes are rearranged in mature B cells
proposing that there are separate genes which code for V and C regions of Ig
30. The heavy chain variable region of all classes/subclasses of Ig are encoded by:
a)
b)
c)
d)
V & C gene segments
V & J gene segments
V gene segments only
V, D, & J gene segments
31. The antigen binding specificity of an antibody is due to:
a)
b)
c)
d)
the constant regions of the light chains
the variable framework regions of the heavy & light chains
the variable regions of the heavy chains
the hypervariable regions of both heavy & light chains
32. If a pre-B cell fails to productively rearrange the heavy chain genes on both
chromosomes, the result is:
a)
b)
c)
d)
the light chains will then attempt to rearrange
the cell will undergo apoptosis
the cell will begin to divide
the cell will become an NK cell
33. If the fourth polyadenylation site on a heavy chain primary transcript is utilized, which
of the following types of Ig would be synthesized:
a)
b)
c)
d)
membrane IgM
membrane IgD
secreted IgM
secreted IgD
34. The heavy chain class switch is regulated by:
a)
b)
c)
d)
T helper cytokines
antigen presenting cells such as macrophages
RAG 1 and RAG 2 genes
none of the above
35. If the heavy chain variable region gene segments of Ig are followed by heptamer 23
nonamer consensus sequences, then:
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a)
b)
c)
d)
the J segments should be preceeded by heptamer 23 nonamer sequences
the D segments should by flanked on either side by heptamer 23 nonamer sequences
the D segments should be preceeded by the heptamer 23 nonamer sequence
a heptamer 12 nonamer sequence would be found following each J segment
36. Terminal deoxynucleotidyl transferase activity contributes to which of the following:
a)
b)
c)
d)
recombinatorial diversity
somatic mutation
combinatorial diversity
junctional diversity
37. IFN g triggers which of the following heavy class switches:
a)
b)
c)
d)
IgM-----IgG1
IgG1--->IgE
IgM-----> IgG2a
IgM----IgA2
38. Somatic mutations occur with high frequency within Ig:
a)
b)
c)
d)
CH1 domains
VH and VL domains
CH2 and CH3 domains
leader sequence domains
39. k and l light chain genes:
a)
b)
c)
d)
are located on the same chromosome
are heavy chain isotype specific
can both be expressed by in the same B cell
none of the above
40. The human MHC complex is referred to as :
a)
b)
c)
d)
the H-2 complex
the B complex
the HLA complex
none of the above
41. If you cross a BALB/C (H-2d) mouse with a CBA (H-2k) mouse, what MHC molecules
will be present on individual cells of the F1?
a)
b)
c)
d)
H-2d allelelic forms only
H-2k allelic forms only
either H-2k or H-2d allelic forms
both H-2k and H-2d allelic forms
42. Which of the following heavy chain class switches would NOT be possible?
a) IgM------->IgG1
c) IgG1------->IgE
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b) IgE-------->IgG1
d) IgM-------->IgA1
Fill in the Blank (1pt per blank)
43. Multiple myeloma patients excrete light chains of immunoglobulin in their urine.
These light chains have been termed..?
44. Areas with very little variability within the variable region domains of heavy and light
chains of Ig are termed..?
45. Each individual idiotypic determinant is termed a(n)..?
The sum of all idiotypic determinants for a given Ig is termed its ..?
46. The acronym CDR stands for..?
47. The ability of a single B cell to simulataneously express IgM and IgD on its surface is
due to..?
48. Heptamer nonamer signal sequences are believed to be recognized by specific
enzymes known as..?
49. The Ig heavy chain genes of only one of the homologous chromosomes is
expressed in a given B lymphocyte. This phenomenon is termed ..?
50. The acronmym MHC stands for..?
51. Two mouse strains which are genetically identical except at a single genetic locus
are termed..?
52. The MHC genes are inherited in 2 sets, one from each parent. Each of these sets is
referred to as a(n)..?
Short Answer Questions (point values as indicated)
53. In the space below, list 4 of the effector functions of immunoglobulin. (2pts)
54. What does the acronym ADCC stand for? (3pts)
Give two types of cells which participate in this immune mechanism.
55. In the space below, diagram the germline configuration of the k or l light chain
genes of humans.
Just below the diagram, give 1 possible configuration following rearrangement. (4pts)
56. Diagram the germline configuration of the heavy chain genes of mouse OR human
Ig. Please show switch regions with a star.
Draw the DNA configuration which would result from one heavy class switch from IgM-----IgA1 (5pts)
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57. Refer to the stick figure of IgG in the space below. Label the polypeptide chains and
show the positions of interchain disulfide bonds.
Then diagram the results of treatment of the IgG with mercaptoethanol. Label the
fragments which would be created and provide labels.
(4pts)
58. Briefly explain the mechanism which prevents non-rearranged immunoglobulin
genes from being transcribed.
(3pts)
59. A patient has been discovered to have a genetic defect in the RAG 1 gene. How
would this defect be expected to affect the indivdual’s immune system? Please be
specific in your answer (3pts)
60. List give the Class I gene loci for mice or humans (please indicate which type you
are listing) (2pts)
61. Give one advantage and one disadvantage of N-nucleotide addition during the rearrangement
of Ig heavy chain gene segments. (2pts)
Sample Questions for Exam 4
(December 12 - Tuesday @ 9:45 am)
MULTIPLE CHOICE: Circle the letter corresponding to the ONE answer for each question.
1. Which statement about hypersensitivity is correct?
a. Type III and type II hypersensitivity are similar, but differ in that type III reactions
involve "self" antigens and type II reactions do not.
b. Mediators of type IV hypersensitivity include IFN-gamma as well as factors that affect
macrophage chemotaxis or migration.
c. Histamine and leukotrienes, both released by mast cells, are mediators of inflammation,
but not hypersensitivity reactions.
2. Which statement about immune mechanisms is correct?
a. Activated macrophages lyse target cells by secreting perforins onto their surfaces,
followed by granzymes, which trigger apoptosis.
b. Activated CTLs contain more lysosomal enzymes and generate more reactive oxygen
intermediates (H2O2, etc.) than Tc precursor cells.
c. Nitric oxide synthase and indoleamine dioxygenase are enzymes, each of which restricts
intracellular pathogens access to an essential amino acid.
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MATCHING MULTIPLE CHOICE: Choose the BEST answer. An answer may be used more
than once within a set of questions.
Answers to questions 3-4:
a. CTLs
b. Macrophages
c. Eosinophils
d. NK cells
e. More than one of these
3. Immunity against the larval forms of certain intestinal parasites can involve the
participation of _____, and these cells also accumulate at sites where atopic
hypersensitivity reactions are occurring so this effect is often used by pathologists as
indicators of this type of hypersensitivity reaction.
4. _____ participate in antibody-dependent cellular cytotoxicity (ADCC) by virtue of having
FcR and granules that contain factors that can lyse target cells.
TRUE-FALSE: If a statement is TRUE, enter A in the blank; if it is FALSE, enter B.
5. Arthus reactions are typified by formation of bulky immune complexes in the kidneys,
lungs, and joints, whereas serum sickness is typified by formation of soluble immune
complexes at a local site of administration of the eliciting dose of antigen.
6. The hemostasis observed in acute inflammatory responses results from constriction of the
arteries and dilation of the veins in the immediate area, and results in the exudation of
fluid, but not cells, into an area where cell damage has occurred.
Answering these essay questions will lead you to a better
understanding of the concepts we covered during the fourth
section of this course.
The mythical Gram-negative extracellular bacterium, Stevensonella pulmonensis, causes a disease
called acute miamitis as the result of its thick capsule and production of a toxin that causes
buildup of fluid in the lungs. Which immune mechanism(s) would be effective against this
bacterium and why? Antibody specific for the toxin would be helpful because it might neutralize
the toxin by preventing its interaction with cellular targets. Activated macrophages would be
required because these cells would be able to prevent intracellular multiplication of this pathogen.
Opsonizing antibody specific for capsular antigens might be helpful because it would be able to
enhance phagocytosis of the bacterium by neutrophils, which could then kill it intracellularly.
ADCC mediated by NK cells would be a primary line of defense against this pathogen because it
would provide for its complement mediated lysis.
Define each of these terms, then briefly explain the relationships among them:
Lymphocyte Natural killer (NK) cell Cytotoxic T lymphocyte (CTL) Relationships -
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Answering these essay questions will lead you to a better
understanding of the concepts we covered during this course ...
and at least two of them will be on the final exam.
Generate a single overview diagram that shows how Th1 and Th2 cells interact with APCs, B
cells, Tc cells, and macrophages to assist in generation of antibody responses, CTL responses and
activated macrophage responses, respectively. (Note: Be certain to label each of the cells, indicate
the cytokines involved, and provide brief descriptions of the processes that occur as a result of
each of the interactions.)
Generate a diagram that depicts the events in T cell signaling (both signal 1 and signal 2) then
compare and contrast (in words) this pathway with the events that occur in B cell signaling (both
signal 1 and signal 2).
Generate a diagram that depicts the events in T cell development in the thymus, then compare and
contrast (in words) this pathway with the events that occur in B cell development in the bone
marrow.
Describe the process of apoptosis, and then explain how it is induced and carried out in each of
these instances:
a. Positive and negative selection in either T or B cell development
b. Regulation of T cell responses
c. NK cell and CTL function
d. Eosinophil function
Discuss (at the mechanistic level) the role of antigen processing and presentation in determining
the outcome of an immune response against each of these:
a. Extracellular parasite
b. Obligate intracellular parasite
c. Facultative intracellular parasite.
(To answer this question, you will need to choose a specific microbe that is applicable to
each of these situations, and you will need to explain, in detail, how the antigen processing
pathways used in each instance influence the response.)
Discuss, in general, how receptors function vis-à-vis binding of ligand and initiation of
intracellular signaling, then explain how this works for each of these:
a. IFN-gamma receptor
b. TCR
c. BCR and B cell coreceptor
Describe, in detail, the mechanisms involved in generating TCR diversity, then compare and
contrast these mechanisms with those involved in generating:
a. BCR diversity
b. MHC diversity
Discuss the relationships between immunoglobulin structures of all five classes (IgG, IgM, IgA,
IgD, IgE) of antibody and the functions that each of these types of antibody can carry out in
antibody mediated immunity, including complement interactions.
Discuss the mechanisms or activation and regulation of the three complement activation pathways
we discussed in class, then explain why each of the negative regulatory processes is necessary to
prevent hypersensitivity and/or autoimmunity reactions.
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Draw a series of diagrams (one for each major step) depicting the events involved in margination
and diapedesis of PMNs. In your diagrams, be sure to include cell surface molecule interactions,
chemokines that influence these interactions, and the process of diapedesis. Also, be sure to label
every component and to include short descriptions of what is occurring in each diagram. Finally,
compare and contrast this series of events with those that occur during emigration of lymphocytes
from the bloodstream into lymphoid tissue.
Generate a series of diagrams (one for each major step) depicting the sequence of interactions
involved in activation of a B cell by a Th cell, starting with binding antigen to BCRs, and
finishing with activation of the B cell by cytokines secreted by the Th cell. Be certain that your
diagrams are clearly labeled, and complete your answer by adding a text description that outlines
the mechanisms involved in each step.
Describe the process of cross-presentation of antigen, then explain, in mechanistic detail, how it
would be helpful in development of immune responses against:
a. tumor cells
b. facultative intracellular parasites
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