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)
- Why are mutations in the spike protein of special interest in regard to vaccine evasion? Because the spike protein is the target of COVID-19 vaccines. Because mutations in the spike protein always are in the receptor-binding domain (RBD). Because spike protein mutations are associated with increased virus transmission. Because the gene for the spike protein mutates faster than the other genes. Because spike protein mutations are associated with increased disease severity.arrow_forward1) 286 individuals were newly diagnosed with Human Immunodeficiency Virus in 2018 in Minnesota. Of these individuals, 76% were male. HIV is an enveloped, ssRNA virus_ Baltimore classification VI. This virus targets CD4+ cells. CD4 refers to a glycoprotein which serves as a co-receptor for T-cells, located on T-helper and T-reg immune cells. a) What part of the HIV virus allows for specificity to CD4+ cells?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_forwardToll-like receptors represent an ancient pathogen-recognition system. The first pattern recognition receptor (PRR) important in innate immune responses was discovered in the fruit fly Drosophila melanogaster. Stimulation of this receptor, called Toll, induces: The synthesis of prostaglandins and leukotrienes The inflammatory response in Drosophila hemolymph vessels The production of antimicrobial peptides The recruitment of phagocytic cells to the site of infection The activation of Drosophila complementarrow_forwardGiven what we know about HIV, describe the impact of this virus on humoral and cellular immunity. [hint - HIV targets CD4 cells; how will this impact an immune response]arrow_forward
- picture 1 shows the directed migration of two immune cell types, neutrophils (red) and macrophages (green) to a laser-induced injury in the ear of a mouse. As you can observe from the video, there are three stages to this process: 1) an initial phase characterized by fast recruitment of neutrophils (red) to the site of injury followed by 2) the slower recruitment of macrophages after which 3) the interaction between both cell types is stabilized. Recruitment to the injury site is mediated by leukotriene B4 (LTB4), a potent immune signaling molecule (Figure 1A). LTB4 binds to BLT1, a G-protein coupled receptor (GPCR), activating various signaling pathways and resulting in immune cell migration to the site of injury (Figure 1B). With this background information and your knowledge of cell and molecular biology, describe in detail in your own words, as many molecular processes as you can identify that must take place for the cell migration process depicted in the video to be achieved. For…arrow_forwardExplain : Vpr counteracts LAPTM5 to promote HIV-1 infection in macrophagesarrow_forwardA 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_forward
- In 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_forwardSome pathogenic microorganisms encode proteins, such as the Staphylococcus Protein A, that bind to immunoglobulin constant region domains with high affinity. These microbial proteins provide a benefit to the microorganism by: Preventing antibodies bound to the microbe from binding to Fc receptors on phagocytes Blocking the binding of anti-microbial antibodies to the pathogen surface Cleaving the antibody into fragments that separate the antigen-binding region from the effector function Inducing aggregation of the anti-microbial antibodies by multivalent binding to the pathogen-derived protein Preventing the antibody from neutralizing the pathogenarrow_forwardA researcher performs an experiment where he infects 2 mice (Mouse A and Mouse B) with herpes simplex virus (HSV). To measure the cytotoxicity of CD8+ T cells from Mouse A, he isolates CD8+ T cells from Mouse A and co-cultures them with a mixture of HSV-infected spleen cells from Mouse B. A day later, he checks the co-culture, but none of the infected spleen cells from Mouse B have been killed. What could explain this observation? a.Mouse B does not express the invariant chain (Ii) b.Mouse A and Mouse B express different MHC alleles c.Mouse A does not express TLR2/6 d.HSV immunoevasins block MHC-II expressionarrow_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