Virus infections induce production of interferons that act on infected cells to enhance their recognition by CD8 cytotoxic T cells. To counter these mechanisms, viruses often encode proteins that interfere with antigen processing and presentation. In an experiment, cells infected with Virus X are treated with interferon and compared with uninfected cells treated with interferon. Proteasomes are isolated from the two cell populations and their enzymatic activities are compared. The data in figure below show the amino acid preferences for cleavage of peptides by the two samples of proteasomes. Based on these data, Virus X most likely encodes a protein that interferes with: The expression of MHC class I on the surface of the infected cell The rate at which peptides are produced from intact proteins in the infected cell The transport of peptides from the cytosol to the endoplasmic reticulum in the infected cell The replacement of constitutive proteasome subunits with immunoproteasome subunits in the infected cell The development of CD8 T cells in the thymus by inhibiting the thymoproteasome
Virus infections induce production of interferons that act on infected cells to enhance their recognition by CD8 cytotoxic T cells. To counter these mechanisms, viruses often encode proteins that interfere with antigen processing and presentation. In an experiment, cells infected with Virus X are treated with interferon and compared with uninfected cells treated with interferon. Proteasomes are isolated from the two cell populations and their enzymatic activities are compared. The data in figure below show the amino acid preferences for cleavage of peptides by the two samples of proteasomes. Based on these data, Virus X most likely encodes a protein that interferes with: The expression of MHC class I on the surface of the infected cell The rate at which peptides are produced from intact proteins in the infected cell The transport of peptides from the cytosol to the endoplasmic reticulum in the infected cell The replacement of constitutive proteasome subunits with immunoproteasome subunits in the infected cell The development of CD8 T cells in the thymus by inhibiting the thymoproteasome
Chapter16: Adult And Pediatric Dosages Based On Body Surface Area
Section: Chapter Questions
Problem 7.2P
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Virus infections induce production of interferons that act on infected cells to enhance their recognition by CD8 cytotoxic T cells. To counter these mechanisms, viruses often encode proteins that interfere with antigen processing and presentation. In an experiment, cells infected with Virus X are treated with interferon and compared with uninfected cells treated with interferon. Proteasomes are isolated from the two cell populations and their enzymatic activities are compared. The data in figure below show the amino acid preferences for cleavage of peptides by the two samples of proteasomes.
Based on these data, Virus X most likely encodes a protein that interferes with:
- The expression of MHC class I on the surface of the infected cell
- The rate at which peptides are produced from intact proteins in the infected cell
- The transport of peptides from the cytosol to the endoplasmic reticulum in the infected cell
- The replacement of constitutive proteasome subunits with immunoproteasome subunits in the infected cell
- The development of CD8 T cells in the thymus by inhibiting the thymoproteasome
![The bar graph presented illustrates the percentage of peptides with specific amino acid residues at the first position under two distinct conditions: exposure to Interferon alone (represented by yellow bars) and exposure to both Virus X and Interferon (represented by red bars).
**Graph Details:**
- **Y-Axis:** The y-axis represents the percentage of peptides, ranging from 0% to 25%.
- **X-Axis:** The x-axis lists the amino acid residues at the first position of the peptide, denoted by single-letter codes: L (Leucine), F (Phenylalanine), I (Isoleucine), Y (Tyrosine), D (Aspartic acid), E (Glutamic acid), and Q (Glutamine).
**Interpreting the Data:**
1. **Leucine (L):**
- Interferon: Approximately 23% of peptides.
- Virus X + Interferon: Approximately 10% of peptides.
2. **Phenylalanine (F):**
- Interferon: Approximately 6% of peptides.
- Virus X + Interferon: Approximately 7% of peptides.
3. **Isoleucine (I):**
- Interferon: Approximately 4% of peptides.
- Virus X + Interferon: Approximately 5% of peptides.
4. **Tyrosine (Y):**
- Interferon: Approximately 5% of peptides.
- Virus X + Interferon: Approximately 8% of peptides.
5. **Aspartic Acid (D):**
- Interferon: Approximately 3% of peptides.
- Virus X + Interferon: Approximately 7% of peptides.
6. **Glutamic Acid (E):**
- Interferon: Approximately 4% of peptides.
- Virus X + Interferon: Approximately 6% of peptides.
7. **Glutamine (Q):**
- Interferon: Approximately 2% of peptides.
- Virus X + Interferon: Approximately 4% of peptides.
**Key Observations:**
- The presence of Interferon alone leads to a significantly higher percentage of peptides with Leucine at the first position compared to the co-presence of Virus X and Interferon.
- Under the combined condition of Virus X and Interferon, there is](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F6d85b824-9e64-430d-9b11-a50b2a6610dc%2Fc400356e-000e-4411-9ed4-da82c711e00a%2Ftzxb1i2d_processed.png&w=3840&q=75)
Transcribed Image Text:The bar graph presented illustrates the percentage of peptides with specific amino acid residues at the first position under two distinct conditions: exposure to Interferon alone (represented by yellow bars) and exposure to both Virus X and Interferon (represented by red bars).
**Graph Details:**
- **Y-Axis:** The y-axis represents the percentage of peptides, ranging from 0% to 25%.
- **X-Axis:** The x-axis lists the amino acid residues at the first position of the peptide, denoted by single-letter codes: L (Leucine), F (Phenylalanine), I (Isoleucine), Y (Tyrosine), D (Aspartic acid), E (Glutamic acid), and Q (Glutamine).
**Interpreting the Data:**
1. **Leucine (L):**
- Interferon: Approximately 23% of peptides.
- Virus X + Interferon: Approximately 10% of peptides.
2. **Phenylalanine (F):**
- Interferon: Approximately 6% of peptides.
- Virus X + Interferon: Approximately 7% of peptides.
3. **Isoleucine (I):**
- Interferon: Approximately 4% of peptides.
- Virus X + Interferon: Approximately 5% of peptides.
4. **Tyrosine (Y):**
- Interferon: Approximately 5% of peptides.
- Virus X + Interferon: Approximately 8% of peptides.
5. **Aspartic Acid (D):**
- Interferon: Approximately 3% of peptides.
- Virus X + Interferon: Approximately 7% of peptides.
6. **Glutamic Acid (E):**
- Interferon: Approximately 4% of peptides.
- Virus X + Interferon: Approximately 6% of peptides.
7. **Glutamine (Q):**
- Interferon: Approximately 2% of peptides.
- Virus X + Interferon: Approximately 4% of peptides.
**Key Observations:**
- The presence of Interferon alone leads to a significantly higher percentage of peptides with Leucine at the first position compared to the co-presence of Virus X and Interferon.
- Under the combined condition of Virus X and Interferon, there is
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