Concept explainers
To determine: Whether the given results support the hypothesis that the virus is adapting to host defenses.
Introduction: Human Immunodeficiency Virus (HIV) is a group of retroviruses that are sexually transmitted from one to another. It causes a disease that lead to life-threatening infections called AIDS. Here, the immune system fails or weakens due to viral infection and is accompanied with the development of many infections. Certain proteins called Human Leukocyte Antigens (HLA) are produced and displayed by our cells that act as a marker for the identification of unusual invaders in the body. Each unique marker is produced for the determination of self-cells versus the invaders by the immune system.
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Chapter 20 Solutions
Biology: The Unity and Diversity of Life (MindTap Course List)
- Serum from individuals with high levels of antibody to SARS-CoV2 has been used to treat patients with severe COVID-19. What is ONE way (there are several) that passive immunization with the antibody to the virus could help these patients? HINT: think about what opsonization with antibody could do for the innate immune response.arrow_forwardThe envelope protein gp120 (Glycoprotein 120) is required for the attachment of the HIV virus to CD 4 receptors of target host cells. Identify the immune cells that consist of CD 4 receptors?arrow_forwardOne strategy for vaccine development currently under investigation is the use of pathogen-derived T cell epitopes as a component of the vaccine. For viral pathogens, implementing this strategy involves scanning the predicted amino acid sequences of the viral proteins for likely peptide epitopes that would bind to MHC class I and MHC class II molecules. In addition to the complication of MHC sequence polymorphism in the human population, another complication of this strategy for peptide epitopes that would bind to MHC class II proteins is: The importance of viral proteins containing peptides that are cleaved into 8–10 amino acid long fragments. The ability of viruses to mutate their proteins to avoid MHC anchor residue sequences. The fact that long peptides (>13 amino acids) are rapidly degraded in cells. The fact that MHC class II proteins are intrinsically stable, even in the absence of binding to a peptide. The absence of defined sequence motifs that predict peptide binding to…arrow_forward
- with HIV, explain the mechanism of intracellular infection and the role of reverse transcriptase. What would you explain about the process? What is the significance of the CD4+ count? ( Discuss the meaning of various ranges of CD4 counts.) List 5 opportunistic infections AND describe data to suggest whether or not a patient has such an infection.arrow_forwardWhich of the following is the most likely explanation for an individual who lacks CCR5 as a result of a homozygous defect in the CCR5 gene becoming infected with HIV? a. The mutated CCR5 genes reverted to the normal form, rendering macrophages susceptible to macrophagetropic HIV variants. b. The macrophage-tropic HIV variant entered host cells using CD4 alone. c. The viral nucleic acid alone was taken up by cells, as in cell transformation by bacterial DNA. d. The individual had received a transplant of HIV-infected cells expressing normal CCR5. e. The primary infection involved a lymphocyte-tropic strain of HIV that used CXCR4 as its co-receptor.arrow_forwardWhich of the following is false when considering the CCR5Δ32 mutation? a) The mutation prevents the entry of HIV-1 into a T cell. b) The deletion that produced CCR5Δ32 caused a frameshift which extends the length of the protein product. c) CCR5Δ32 prevents infection by HIV-1 in homozygotes but only delays the onset of HIV symptoms in heterozygotes. d) The protein product produced by CCR5Δ32 is altered in such a manner that it cannot embed in the cell membrane.arrow_forward
- A pathogenesis function f(t)t(t-21)(t + 1) is used to model the development of the disease, where t is measured in days and f(t) represents the number of infected cells per mL of plasma. What is the peak infection time for this virus? (Round your answer to one decimal place.) t= Need Help? X days Read Itarrow_forwardIn Type II innate bacterial immunity, which of the following molecules are required for proper assembly and targeting of the Cas9 protein? MRNA TRNA miRNA SİRNA O crRNA/tracrRNAarrow_forwardModerna and Pfizer vaccines for COVID-19 use mRNA to the Spike protein combined with lipids. Which of the following is/are advantages of this type of vaccine compared to an inactivated virus vaccine? Select ALL correct answers. a) The vaccine is more stable for transport. b) The vaccine does not contain the virus so it cannot give you COVID-19. c) The vaccine can be rapidly produced in a slightly different form to protect from variants of SARS-CoV-2. d) The vaccine does not need a booster.arrow_forward
- 1. Glycoproteins coat the outside of viruses; in particular they are important in helping HIV dock to our cells and also help the virus evade our immune system. Below is an image of the HIV transmembrane gp120 protein docking to human cd4 cells via the CXCR4 receptor. HIV-gp120 HIV CXCR4 Coreceptor CCR5 Coreceptor CD4 Receptor CD4 Cell a) i) Describe the general chemical interactions that might be involved in protein- protein interactions between the HIV gp120 protein and the human cd4 CXCR4 protein. Hypothesize what type of amino acid R groups you might find on the ii) exterior regions of each of these proteins, iii) and on the membrane bound portion of these proteins. b) The tertiary structure of gp120 is shown below. Please describe the protein (make sure to cover primary, secondary, and tertiary levels).arrow_forwardThe experiment shown in thefigure below uses two strains of mice that differ in their MHC genes. Strain A is H-2a and Strain B is H-2b. Mice of each strain are infected with the virus LCMV, and T cells are isolated at day 8 post-infection. These T cells are mixed with target cells that express either H-2a or H-2b; in each case, the target cells are either uninfected or infected with LCMV. After a four-hour incubation of T cells with target cells, the percentage of target cells lysed by the T cells is shown in the graph. The explanation for the results of this experiment is: Mice of strain B do not make a T cell response to LCMV. Mice of strain A make a more robust T cell response to LCMV than mice of strain B. Target cells that express H-2b cannot be infected with LCMV. T cells from mice of strain A only recognize viral peptides on target cells expressing H-2a. LCMV peptides do not bind to MHC class I molecules from H-2b mice.arrow_forwardCan a mouse infected with Bacillus anthracis generate antibodies against the S-layer? How do you know? I need help finding the answer in the article and explain in short answer link to article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC106848/arrow_forward
- Biology: The Unity and Diversity of Life (MindTap...BiologyISBN:9781305073951Author:Cecie Starr, Ralph Taggart, Christine Evers, Lisa StarrPublisher:Cengage LearningHuman Physiology: From Cells to Systems (MindTap ...BiologyISBN:9781285866932Author:Lauralee SherwoodPublisher:Cengage Learning