Viral Path Immun Response MCQ's
Our immune system has a way of treating alien material within the body by noticing what is harmful to the day to day operations of the organs and what is not and creating defensive measure. Take up the viral path immune response MCQ's and get to refresh your memory on what you already know.
- 1.
Which structure serves as the target for neutralizing antibodies when dealing with an enveloped, (-) ssRNA virus?
- A.
RNA
- B.
Capsid
- C.
Lipid bilayer
- D.
Envelope glycoprotein
- E.
RNA polymerase
Correct Answer
D. Envelope glycoproteinExplanation
Neutralizing antibodies target the envelope glycoprotein of enveloped, (-) ssRNA viruses. The envelope glycoprotein is located on the surface of the virus and plays a crucial role in viral entry into host cells. By binding to the envelope glycoprotein, neutralizing antibodies can prevent the virus from attaching to and entering host cells, thereby neutralizing its infectivity. This makes the envelope glycoprotein an important target for developing vaccines and antiviral therapies against enveloped, (-) ssRNA viruses.Rate this question:
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- 2.
An 8-year-old boy is diagnosed with swine flu. His chest x-ray is consistent with a viral pneumonia. Which of the following is responsible for his pneumonia?
- A.
Hemagglutinin and neuraminidase
- B.
Lack of adherence factors
- C.
Phagocytosis by alveolar macrophages
- D.
Toxin that paralyzes cilia of respiratory epithelium
- E.
Phagocytosis by neutrophils
Correct Answer
A. Hemagglutinin and neuraminidaseExplanation
Hemagglutinin and neuraminidase are responsible for the pneumonia in the 8-year-old boy diagnosed with swine flu. These are surface proteins found on the influenza virus. Hemagglutinin helps the virus attach to host cells, while neuraminidase helps the virus release from infected cells. In the case of swine flu, the viral pneumonia is caused by the influenza virus, and the presence of hemagglutinin and neuraminidase indicates the involvement of the virus in the pneumonia.Rate this question:
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- 3.
As a means of virulence, some viruses encode virokines. A case in point is vIL-10 which is encoded by the Epstein-Barr virus (EBV). Which of the following immune functions would be most affected by this virokine?
- A.
The TH1 response
- B.
The TH2 response
- C.
The lectin-binding pathway of complement activation
- D.
The classical pathway of complement activation
- E.
The alternate pathway of complement activation
Correct Answer
A. The TH1 responseExplanation
The TH1 response is the immune function that would be most affected by the virokine vIL-10 encoded by the Epstein-Barr virus (EBV). Virokines are proteins produced by viruses that mimic or interfere with host immune signaling molecules. vIL-10 is a viral mimic of the host cytokine IL-10, which is a key regulator of the TH1 immune response. By mimicking IL-10, vIL-10 can suppress the TH1 response, which is involved in cell-mediated immunity and defense against intracellular pathogens. Therefore, the presence of vIL-10 would likely dampen the TH1 response and impair the immune system's ability to fight off certain infections.Rate this question:
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- 4.
Virulence factors play an important role in the pathogenesis of viral infections, and some of these factors alter host defence mechanisms. One such factor is the HCMV (human cytomegalovirus) U56 protein that inhibits TAP proteins (transporters associated with antigen processing). By inhibiting TAP, which host defence mechanism is affected by U56?
- A.
B-cell-mediated antigen presentation to naive CD4 cells
- B.
CD4+-mediated B-cell activation
- C.
Dendritic cell-mediated antigen presentation to naive CD4+ cells
- D.
Somatic cell-mediated antigen presentation to activated CD8+ ceils CD4+ -mediated CD8+ cell activation
Correct Answer
D. Somatic cell-mediated antigen presentation to activated CD8+ ceils CD4+ -mediated CD8+ cell activationExplanation
The HCMV U56 protein inhibits TAP proteins, which are involved in somatic cell-mediated antigen presentation to activated CD8+ cells. This means that the U56 protein affects the ability of somatic cells to present antigens to activated CD8+ cells, thereby compromising the host's immune response against viral infections.Rate this question:
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- 5.
What would be the phenotype of cells infected with HIV-1 during the primary stage of the infection?
- A.
CD4 CXCR4
- B.
CD8 CCR5
- C.
CD4 CCR5
- D.
CD8 / CXCR4
Correct Answer
C. CD4 CCR5Explanation
During the primary stage of HIV-1 infection, the virus primarily targets and infects CD4 T cells, which are immune cells that express the CD4 receptor. Additionally, the virus binds to the CCR5 co-receptor on the surface of these CD4 T cells. Therefore, the phenotype of cells infected with HIV-1 during the primary stage would be CD4 CCR5.Rate this question:
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- 6.
"Virulence of viruses can be calculated in a number of ways. For Rhinovirus, for example, the HID50 is sometimes given as between 0.1-6 ICID30. What does TCID50 stand for?
- A.
The dose required to infect 50% of tissue culture cells
- B.
The dose required to kill 50% of infected tissue culture cells
- C.
Fifty percent of the dose required to infect all tissue culture cells
- D.
Fifty percent of the dose required to kill infected tissue culture cells
Correct Answer
A. The dose required to infect 50% of tissue culture cellsExplanation
TCID50 stands for Tissue Culture Infective Dose 50. It is a measurement used to determine the concentration of a virus that is needed to infect 50% of a specific type of tissue culture cells. This measurement helps in assessing the infectivity and virulence of a virus.Rate this question:
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- 7.
During most viral infections, lack of which cell surface molecule would be the most likely to cause a major problem to the defense of the host?
- A.
MHC class I
- B.
CD23
- C.
CD14
- D.
CD20
Correct Answer
A. MHC class IExplanation
During viral infections, MHC class I molecules play a crucial role in presenting viral antigens to cytotoxic T cells, which then eliminate infected cells. If there is a lack of MHC class I molecules, the immune system would be unable to recognize and eliminate virus-infected cells effectively. This would result in a major problem for the defense of the host, as the virus could replicate and spread without being targeted by the immune system.Rate this question:
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- 8.
A 32-year old man with AIDS develops symptoms of retinitts. Which enzyme is encoded by the pathogen most likely responsible for the retinitts?
- A.
Integrase
- B.
5N-methyl capping enzyme
- C.
Neuraminidase
- D.
RNA-dependent RNA polymerase
- E.
Thymidine kinase
Correct Answer
E. Thymidine kinaseExplanation
Im guessing its CMVRate this question:
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- 9.
Host defense against viral infections relies on a strong THo,,1 response. The T-helper-1 response is characterized by the secretion of:
- A.
1FN--y and 1L-12
- B.
IL-4 and IFN-y
- C.
IL-4 and 1L-12
- D.
IL-10 and IFN--y
- E.
1L-4 and TNF-ct
Correct Answer
A. 1FN--y and 1L-12Explanation
The correct answer is 1FN--y and 1L-12. The T-helper-1 response is characterized by the secretion of these cytokines. IFN-y is a pro-inflammatory cytokine that plays a crucial role in the defense against viral infections by activating immune cells and enhancing their antiviral functions. IL-12 is another pro-inflammatory cytokine that stimulates the production of IFN-y and promotes the differentiation of T-helper-1 cells. Therefore, a strong TH1 response, characterized by the secretion of IFN-y and IL-12, is important in host defense against viral infections.Rate this question:
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- 10.
When LPS from extracellular Gram-negative bacteria is released into the patient, it interacts with a number of immune pattern recognition receptors which eventually results in activation of macrophages. What molecule initially binds to LPS and transfers this to macrophage-produced CD14?
- A.
MBP
- B.
LBP
- C.
TLR-4
- D.
CRP
Correct Answer
B. LBPExplanation
Lipopolysaccharide-binding protein is a protein that in humans is encoded by the LBP gene.[1][2]
LBP is a soluble acute-phase protein that binds to bacterial lipopolysaccharide (or LPS) to elicit immune responses by presenting the LPS to important cell surface pattern recognition receptors called CD14 and TLR4.[3]
The protein encoded by this gene is involved in the acute-phase immunologic response to gram-negative bacterial infections. Gram-negative bacteria contain a glycolipid, lipopolysaccharide (LPS), on their outer cell wall. Together with bactericidal permeability-increasing protein (BPI), the encoded protein binds LPS and interacts with the CD14 receptor, probably playing a role in regulating LPS-dependent monocyte responses.Rate this question:
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- 11.
You are now aware that there are a number of T cell types associated with specfic immune responses to particular pathogens. Which type of pathogen would you most associate with TH17 responses?
- A.
Intracellular bacteria
- B.
Extracellular bacteria
- C.
Metazoan parasites
- D.
Viruses
Correct Answer
B. Extracellular bacteriaExplanation
TH17 responses are primarily associated with extracellular bacteria. This is because TH17 cells are involved in the immune response against pathogens that reside outside of host cells, such as bacteria that infect the extracellular spaces of tissues. These cells help recruit other immune cells to the site of infection and promote the production of antimicrobial peptides and pro-inflammatory cytokines to eliminate the bacteria. Intracellular bacteria, on the other hand, are targeted by other T cell types such as TH1 cells. Metazoan parasites and viruses also elicit different immune responses, involving different types of T cells.Rate this question:
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- 12.
A 23-year-old male patient presents with urethritis, including balanitis; arthritis, and uni;ateral uveitis. He admits to unprotected sex with a number of partners but denies any indications of a sexually transmitted disease. However, upon questioning the patient does admit that he might have had a temporary, slight, milky discharge from his urethra, which he had dismissed as being of no significance. While you are waiting for laboratory test results which of the following might you consider likely?
- A.
The patient had been infected by Neisseria gonnorrhoeae and would have low serum Rf levels
- B.
The patlent had not been infected with any infectious agent but would have high serum Rf levels
- C.
The patient had been infected with Neisseria gonnorrhoeae and would have high serum Rf
- D.
The patient had been infected with Chlamydia trachomatis and would have low serum Rf levels
- E.
The patient had been infected with Chlarnyclia trachornaris and would have high serum Rf levels
Correct Answer
D. The patient had been infected with Chlamydia trachomatis and would have low serum Rf levelsExplanation
The patient's symptoms of urethritis, balanitis, arthritis, and unilateral uveitis, along with a history of unprotected sex, suggest a sexually transmitted infection. The fact that the patient had a temporary, milky discharge from his urethra further supports this. Chlamydia trachomatis is a common cause of urethritis and can also lead to complications such as reactive arthritis and uveitis. Rheumatoid factor (Rf) levels are typically low in Chlamydia infections. Therefore, it is likely that the patient has been infected with Chlamydia trachomatis and would have low serum Rf levels.Rate this question:
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Mar 21, 2023Quiz Edited by
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May 07, 2012Quiz Created by
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