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c. destroy virus-infected host cells.
The role of CTLs in immune responses against viruses is to
a. neutralize viral activity.
b. promote destruction of viruses by ADCC.
c. destroy virus-infected host cells.
d. attack free virions.
d. all of the above.
Viruses can escape immune defenses by
a. undergoing frequent genetic mutations.
b. suppressing the immune system.
c. integrating their nucleic acid into the host genome.
d. all of the above.
b. IgM-, IgG+
A patient who has developed immunity to a viral infection would be expected to have which of the following serology results?
a. IgM+, IgG-
b. IgM-, IgG+
c. IgM+, IgG+
d. IgM-, IgG-
a. IgM
A newborn suspected of having a congenital viral infection should be tested for virus-specific antibodies of which class(es)?
a. IgM
b. IgG
c. IgA
d. All of the above classes
d. Hepatitis E
Which of the following hepatitis viruses is transmitted by the fecal-oral route?
a. Hepatitis B
b. Hepatitis C
c. Hepatitis D
d. Hepatitis E
b. acute hepatitis B.
An individual with hepatomegaly, jaundice, and elevated liver enzymes has the following laboratory results: IgM anti-HAV (negative), HBsAg (positive), IgM anti-HBc (positive), and anti-HCV (negative). These findings support a diagnosis of
a. hepatitis A.
b. acute hepatitis B.
c. chronic hepatitis B.
d. hepatitis C.
a. anti-HBs.
The serum of an individual who received all doses of the hepatitis B vaccine should contain
a. anti-HBs.
b. anti-HBe.
c. anti-HBc.
d. all of the above.
d. monitor hepatitis C patients on antiviral therapy.
Quantitative tests for HCV RNA are used to
a. screen for hepatitis C.
b. determine the HCV genotype.
c. differentiate acute HCV infection from chronic HCV infection.
d. monitor hepatitis C patients on antiviral therapy.
c. sheep erythrocyte antigens.
In the laboratory, heterophile antibodies are routinely detected by their reaction with
a. B lymphocytes.
b. bovine erythrocyte antigens.
c. sheep erythrocyte antigens.
d. Epstein-Barr virus antigens.
c. congenital infection with the rubella virus.
The presence of IgM anti-rubella antibodies in the serum from an infant born with a rash suggests
a. a diagnosis of measles.
b. a diagnosis of German measles.
c. congenital infection with the rubella virus.
d. passive transfer of maternal antibodies to the infant's serum.
c. Yes, a greater than four-fold rise in titer indicates early infection.
A pregnant woman is exposed to a child with a rubella infection. She had no clinical symptoms but had a rubella titer performed. Her antibody titer was 1:8. Three weeks later, the test was repeated and her titer was 1:128. She still had no clinical symptoms. Was the laboratory finding indicative of rubella infection?
a. No, the titer must be greater than 256 to be significant.
b. No, the change in titer is not significant if no clinical signs are present.
c. Yes, a greater than four-fold rise in titer indicates early infection.
d. Yes, but clinical symptoms must also correlate with laboratory findings.
c. varicella-zoster virus.
The cause of shingles is the
a. cytomegalovirus.
b. rubella virus.
c. varicella-zoster virus.
d. HTLV-I.
d. real-time PCR.
The method of choice for detecting VZV infection in immunocompromised hosts is
a. serology to detect virus-specific IgM antibodies.
b. serology to detect virus-specific IgG antibodies.
c. viral culture.
d. real-time PCR.
a. RT-PCR is recommended as the primary diagnostic test.
Which of the following is true regarding laboratory testing for mumps?
a. RT-PCR is recommended as the primary diagnostic test.
b. Serology is necessary for confirmation of a suspected clinical case.
c. IgM tests for mumps are highly specific.
d. An acute infection must be confirmed by a four-fold
rise in IgG titer.
c. confirmed by Western blot.
A positive result on a screening test for HTLV-I antibody should be
a. considered highly specific for HTLV-I infection.
b. followed by PCR.
c. confirmed by Western blot.
d. validated by viral culture.
