Disease and Infection Definitions
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Questions and Answers

What is the main difference between disease and infection?

  • Disease involves a characteristic set of signs and symptoms, while infection is the presence of an organism. (correct)
  • Disease always results in known prognosis, while infection may be clinically unapparent.
  • Infection is caused by an infectious agent, while disease is the introduction of a viral genome into a host cell.
  • Disease is always detected by signs, while infection may not manifest any symptoms.

    • What is the definition of colonization as mentioned in the text?

  • Temporary introduction of an organism into the body without growth, often resulting in clinical symptoms.
  • Transient introduction of a metazoan organism into the body without any possibility of leading to disease.
  • Permanent introduction of an organism into the body accompanied by multiplication, which may lead to disease. (correct)
  • Introduction of a virus genome into a host cell followed by rapid multiplication within the cell.

    • What does tropism refer to in the context of infectious diseases?

  • The introduction of a disease organism from one host to another.
  • The transient or permanent introduction of organisms into the body.
  • The reservoir where infectious agents are permanently maintained.
  • The specific predilection of a virus to infect certain cells, tissues, or organs. (correct)

    • What defines a vector in the transmission of diseases?

    <p>An agent that transmits a disease organism from one host to another.</p> Signup and view all the answers

    Which term refers to the presence of virions in the blood?

    <p>Viremia</p> Signup and view all the answers

    What does 'virulence' primarily refer to?

    <p>Severity of disease caused</p> Signup and view all the answers

    Which term describes a nonessential gene that enhances an organism's virulence when expressed?

    <p>Virulence factor</p> Signup and view all the answers

    What does 'attenuation' refer to in virology?

    <p>Loss of virulence</p> Signup and view all the answers

    What is meant by 'persistent (chronic) infection'?

    <p>Failure to clear the infection</p> Signup and view all the answers

    'Latent infection' is characterized by which of the following?

    <p>Presence of an intact viral genome</p> Signup and view all the answers

    'Smoldering infection' refers to what condition?

    <p>Low-level viral replication despite immune response</p> Signup and view all the answers

    'Transforming infection' is characterized by what process?

    <p>Cell immortalization</p> Signup and view all the answers

    What is the defining characteristic of an infectious disease?

    <p>Deviation from normal structure or function of body part with characteristic signs and symptoms</p> Signup and view all the answers

    What does the term 'colonization' refer to?

    <p>Permanent introduction and growth of an organism in or on the body</p> Signup and view all the answers

    Which term describes an organism's predilection to infect certain cells, tissues, organs, or systems?

    <p>Tropism</p> Signup and view all the answers

    What is the role of a vector in disease transmission?

    <p>Transmitting the disease organism from one host to another</p> Signup and view all the answers

    What is the term for the loss of virulence in an organism?

    <p>Attenuation</p> Signup and view all the answers

    Which condition is characterized by low-level viral replication despite an efficient immune response?

    <p>Smoldering infection</p> Signup and view all the answers

    What does 'cytopathic effect' refer to in virology?

    <p>Cytopathic alteration</p> Signup and view all the answers

    Which term describes a mixture of viruses present in a host at one time derived from a common ancestral virus?

    <p>Quasispecies</p> Signup and view all the answers

    What characterizes an acute infection?

    <p>Self-limiting infection with rapid onset and resolution</p> Signup and view all the answers

    What is the term for the capacity of a virus to enter and cause damage to a tissue?

    <p>Invasiveness</p> Signup and view all the answers

    'Persistent infection' refers to what condition?

    <p>Failure of the host to clear the infection</p> Signup and view all the answers

    'Slow infection' is characterized by what aspect?

    <p>Long incubation period prior to symptom appearance</p> Signup and view all the answers

    'Oncogenesis' refers to which process?

    <p>'Process through which healthy cells become transformed into cancer cells'</p> Signup and view all the answers

    What does 'virus restriction' relate to in virology?

    <p>'Mutational load that leads to viral genome degradation'</p> Signup and view all the answers

    What characterizes 'abortive (nonproductive) infection'?

    <p>Not leading to the production of progeny virions</p> Signup and view all the answers

    What is a key requirement for a virus to overcome host defenses?

    <p>Gains access to the host with a minimal virus inoculum</p> Signup and view all the answers

    Which factor is crucial for a virus to avoid local and systemic antiviral defenses?

    <p>Induction of harmful host immune responses</p> Signup and view all the answers

    How can a virus cause host damage through direct cell destruction?

    <p>By cell lysis due to viral replication cycle completion</p> Signup and view all the answers

    What determines the outcome of a viral infection according to the text?

    <p>The balance between factors promoting disease and guarding against it</p> Signup and view all the answers

    Which pattern of infection is characterized by recurring disease episodes separated by asymptomatic periods?

    <p>Cyclic disease</p> Signup and view all the answers

    Which virus is an example of a pathogen responsible for persistent infection?

    <p>Hepatitis B virus</p> Signup and view all the answers

    What characterizes the recurrence of disease in cyclic infections?

    <p>Initial disease is always milder than recurrences</p> Signup and view all the answers

    Which type of infection is characterized by a continuous buildup of the pathogen after an initial acute phase?

    <p>Slow infection</p> Signup and view all the answers

    In which type of infection do individuals recover from the initial acute illness but the pathogen remains latent for indeterminate periods?

    <p>Cyclic disease</p> Signup and view all the answers

    Which characteristic is typical of slow infections caused by retroviruses like HIV-1?

    <p>Continuous buildup of the pathogen after recovery from acute illness</p> Signup and view all the answers

    What can tip the balance in favor of illness or exacerbate it according to the text?

    <p>Viral strain</p> Signup and view all the answers

    Which factor mentioned can render the immune system less effective and efficient?

    <p>Healthy nutritional status</p> Signup and view all the answers

    In the context of viral infections, what is the meaning of 'non-productive or abortive' infection?

    <p>No progeny virions are produced during infection</p> Signup and view all the answers

    Which situation makes it easier for some individuals to get infected and suffer disease according to the text?

    <p>Expression of certain MHC-I alleles</p> Signup and view all the answers

    Which viral perspective is highlighted as irrelevant when considering the replicative cycle in the text?

    <p>Outcome of delivery of viral nucleic acid</p> Signup and view all the answers

    Which stage of viral disease is responsible for non-specific, general symptoms like fever or malaise?

    <p>Initiation of infection</p> Signup and view all the answers

    During which phase of viral disease can characteristic signs be recognized such as respiratory illness or hepatitis?

    <p>Symptomatic period</p> Signup and view all the answers

    Which phase is usually associated with the resolution of viral disease?

    <p>Convalescence</p> Signup and view all the answers

    Which phase is characterized by the limitation of disease through viral control and/or clearance?

    <p>Immune responses</p> Signup and view all the answers

    When can transmission of a viral disease occur according to the stages mentioned?

    <p>After replication in target tissue</p> Signup and view all the answers

    Which type of viral infection involves the host becoming permanently infected?

    <p>Persistent infection</p> Signup and view all the answers

    Which pattern of disease progression involves the pathogen being completely eliminated by the host's immune system?

    <p>'Acute' disease pattern</p> Signup and view all the answers

    What is a characteristic of acute subclinical infections according to the text?

    <p>'Overt' disease symptoms present</p> Signup and view all the answers

    'Rhinoviruses' causing the common cold are an example of which type of infection?

    <p>'Acute' subclinical infection</p> Signup and view all the answers

    'Hepatitis B virus' can present as self-limited or persistent depending on what factor?

    <p>'Pathogen virulence'</p> Signup and view all the answers

    Which stage is responsible for viral amplification in many viral infections according to the text?

    <p>Incubation period</p> Signup and view all the answers

    When do some infections go completely undetected according to the text?

    <p>During some or all steps</p> Signup and view all the answers

    What does MOI stand for in virology?

    <p>Multiplicity Of Infection</p> Signup and view all the answers

    What does TCID50 stand for in virology?

    <p>Tissue Culture Infective Dose 50</p> Signup and view all the answers

    Which metric measures the number of infectious particles required to infect 50% of the cells?

    <p>ID50/cell</p> Signup and view all the answers

    What is the definition of Multiplicities of Infection?

    <p>The number of viral particles per unit volume</p> Signup and view all the answers

    What does the term HID50 refer to in the context of viral infections?

    <p>The infectious dose required to infect half of the inoculated individuals</p> Signup and view all the answers

    Why are enveloped viruses particularly sensitive to desiccation?

    <p>Enveloped structure makes them susceptible to drying out</p> Signup and view all the answers

    What is the role of vectors in viral transmission?

    <p>To amplify viral numbers and provide shelter during transit</p> Signup and view all the answers

    How do naked viruses differ from enveloped viruses in terms of environmental resistance?

    <p>Naked viruses are generally well-suited to withstand unfavorable conditions</p> Signup and view all the answers

    Which phase of viral disease is associated with viral amplification and spread to other hosts?

    <p>Transmission phase</p> Signup and view all the answers

    What is a critical factor that enables viruses to overcome host defenses during transmission?

    <p>Structural characteristics for environmental resistance</p> Signup and view all the answers

    In what way do some genetic backgrounds influence the likelihood of HIV-1 infection?

    <p>By increasing the probability of infection during sexual encounters</p> Signup and view all the answers

    How do viruses exploit vectors to aid in their transmission?

    <p>By replicating within vectorial host cells and amplifying viral numbers</p> Signup and view all the answers

    Which aspect of viral surface structures determines tissue tropism and pathology?

    <p>Cellular adhesion properties</p> Signup and view all the answers

    What is a common strategy employed by many viruses to ensure successful transmission between hosts?

    <p>High replication rates leading to sufficient yields</p> Signup and view all the answers

    How do some viruses resist harsh environmental conditions while in transit from one host to another?

    <p>By possessing outer proteinaceous protective capsids</p> Signup and view all the answers

    How can viruses infect inflammatory cells such as CD4 T lymphocytes?

    <p>Via transport by M cells associated with GALTs</p> Signup and view all the answers

    In viral spread, what is a characteristic of systemic spread within a host?

    <p>Viral particles are carried by the host's circulatory systems</p> Signup and view all the answers

    How do paramyxoviruses primarily move from cell to cell?

    <p>Via membrane fusion between adjoining cells</p> Signup and view all the answers

    Which type of viruses mainly cause persistent infections with minimal cytolysis?

    <p>Herpesvirus</p> Signup and view all the answers

    Which characteristic is associated with the infection of Kupffer cells in the liver by viruses?

    <p>Spreading hepatitis viruses to hepatocytes</p> Signup and view all the answers

    What is a characteristic of the flu caused by Influenza virus A?

    <p>Only causes acute infections</p> Signup and view all the answers

    How do viruses usually gain access to the central nervous system (CNS) according to the text?

    <p>By crossing through endothelial cells or between them</p> Signup and view all the answers

    What is a common feature of human papillomaviruses and the virus responsible for hepatitis A mentioned in the text?

    <p>They lead to persistent infections independent of cytolysis</p> Signup and view all the answers

    What is a direct pathological effect of herpesvirus infection on cells?

    <p>Altered surface molecules</p> Signup and view all the answers

    What is a defining characteristic of bronchiolitis caused by paramyxoviruses according to the text?

    <p>'Syncytia formation' between infected cells</p> Signup and view all the answers

    Which viral component can be toxic to cells at high concentrations?

    <p>Viral particles</p> Signup and view all the answers

    How do viruses usually establish latency in neural sensory ganglia according to the text?

    <p>'Retrograde transport' via neuromuscular junctions</p> Signup and view all the answers

    What contributes to herpetic skin lesions caused by herpesvirus infection?

    <p>Cell membrane lysis</p> Signup and view all the answers

    What can facilitate viruses' entry into the central nervous system (CNS) according to the text?

    <p>'Leukocyte circulation' from inflammatory sites</p> Signup and view all the answers

    Which virus is known to produce an enterotoxin affecting electrolyte secretion in enterocytes?

    <p>Rotavirus</p> Signup and view all the answers

    'Viral spread can occur at different scales but with overlap.' What does 'local dissemination' primarily refer to according to the text?

    <p>'Membrane fusion' between adjacent respiratory cells</p> Signup and view all the answers

    What can be toxic and induce cell death in the context of HIV infection?

    <p>Viral envelope proteins</p> Signup and view all the answers

    What contributes to most hepatocyte killing during hepatitis infection?

    <p>[Picornaviridae] infection</p> Signup and view all the answers

    How do slow infections caused by retroviruses like HIV-1 differ from acute infections?

    <p>Acute infections involve recurring disease episodes.</p> Signup and view all the answers

    What is the role of increased vascular permeability in common cold pathology?

    <p>Symptoms associated with plasma protein levels.</p> Signup and view all the answers

    What contributes directly to many hemorrhagic fevers according to the text?

    <p>Local inflammatory processes.</p> Signup and view all the answers

    Which factor contributes to the severe manifestations of viral diseases?

    <p>Increased TNF-α expression</p> Signup and view all the answers

    What is the primary cause of lower respiratory tract viral diseases like bronchiolitis or influenza?

    <p>Combination of viral tissue destruction and inflammatory processes</p> Signup and view all the answers

    How do some viral infections lead to transient bone marrow output variations?

    <p>By altering hematopoiesis</p> Signup and view all the answers

    Which phenomenon is primarily responsible for AIDS patients' extreme susceptibility to opportunistic infections?

    <p>CD4 lymphocyte depletion</p> Signup and view all the answers

    What category do causes of bone marrow suppression resulting from virus infections fall into?

    <p>Direct Infection</p> Signup and view all the answers

    Which cells can be depleted through activation-induced exhaustion during some viral infections?

    <p>Lymphocytes</p> Signup and view all the answers

    What is the main outcome of overproduction of IFN-α, IFN-γ, IL-1β, TNF-α, IL-6, and CSFs on HSCs?

    <p>Proliferation and differentiation impairment</p> Signup and view all the answers

    What can viral recognition receptor engagement lead to in terms of HSCs?

    <p>Apoptotic pathway activation</p> Signup and view all the answers

    What is the primary mechanism behind the severe manifestations associated with most viral diseases?

    <p>High proinflammatory cytokine expressions</p> Signup and view all the answers

    What is the main result of viral recognition receptor engagement on pathogen recognition receptors in HSCs?

    <p>Skewed leukocyte production</p> Signup and view all the answers

    What effect can chronic exposure to inflammatory mediators have on hematopoietic stem cells (HSCs)?

    <p>Proliferation and differentiation impairment</p> Signup and view all the answers

    What is the primary mechanism by which some viruses induce transient bone marrow output variations?

    <p>Alteration of hematopoiesis</p> Signup and view all the answers

    What is the main mechanism of cell transformation in Endemic Burkitt Lymphoma?

    <p>Insertional mutagenesis</p> Signup and view all the answers

    What chromosomal anomaly is characteristic of 80% of Endemic Burkitt Lymphoma cases?

    <p>t(8;14)</p> Signup and view all the answers

    Which gene promoter controls the constitutive expression of the c-myc protooncogene in Endemic Burkitt Lymphoma?

    <p>IgH gene</p> Signup and view all the answers

    What accounts for the remaining 20% of Endemic Burkitt Lymphoma cases?

    <p>Translocation t(8;22)</p> Signup and view all the answers

    What is the role of HPV E7 protein in cervical/anal/oropharyngeal carcinoma development?

    <p>Binds pRb to free E2f and activate genes involved in cell cycling</p> Signup and view all the answers

    How does the HPV E6 protein contribute to tumorigenesis in cervical/anal/oropharyngeal carcinoma?

    <p>Promotes p53 degradation leading to increased cell growth</p> Signup and view all the answers

    What is the mechanism through which HBV X protein contributes to hepatocellular carcinoma development?

    <p>Activates the transcription of protooncogenes through cell signaling pathways</p> Signup and view all the answers

    What role do virokines play in promoting growth and preventing apoptosis in Kaposi sarcoma?

    <p>Promote cell growth and prevent apoptosis</p> Signup and view all the answers

    How do some viruses increase their rates of replication?

    <p>Through gene expression that increases DNA synthesis</p> Signup and view all the answers

    What is the primary function of viroceptors encoded by large DNA viruses?

    <p>'Dampen' the host's immune response</p> Signup and view all the answers

    How does HCV core protein affect cell cycle control mechanisms?

    <p>Inactivates p21cip to enhance cell cycling</p> Signup and view all the answers

    What is the impact of HPV E7 protein on p21cip in cervical/anal/oropharyngeal carcinoma development?

    <p>'Inactivates' p21cip to allow for cell cycling</p> Signup and view all the answers

    How does Human T lymphotropic virus 1 cause adult T cell leukemia/lymphoma?

    <p>Through gene expression that enhances T cell proliferation</p> Signup and view all the answers

    What is a common mechanism by which many viruses alter host defense mechanisms?

    <p>Expressing viroceptors that dampen the host immune response</p> Signup and view all the answers

    What is the driving force behind genetic drift in viruses?

    <p>Frequent introduction of mutations due to low proofreading capacity</p> Signup and view all the answers

    How do some viruses evade the host's immune response related to antigen presentation?

    <p>Inhibiting MHC and MHC-associated molecules synthesis</p> Signup and view all the answers

    What can result from the accumulation of mutations in viruses over time?

    <p>Formation of quasispecies</p> Signup and view all the answers

    How do some enveloped viruses increase infectivity?

    <p>By incorporating host molecules into their membranes</p> Signup and view all the answers

    What is the significance of immune-privileged sites for certain viruses?

    <p>They are immune-deprived areas allowing viruses to avoid immune defenses</p> Signup and view all the answers

    What can a single cell infected with two distinct strains of Influenza A virus lead to?

    <p>Antigenic shift due to random mutations</p> Signup and view all the answers

    How do some viruses protect themselves from opsonization?

    <p>By binding to Fc fragment of IgGs</p> Signup and view all the answers

    What can the incorporation of host molecules into virion membranes by some enveloped viruses lead to?

    <p>Increased infectivity by strengthening virion-cell interactions</p> Signup and view all the answers

    What can tissue tropism for immune-privileged sites allow certain viruses to do?

    <p>Avoid immune defenses and spread effectively</p> Signup and view all the answers

    How can antigenic shift occur in Influenza A virus?

    <p>By accidental incorporation of segments from different strains during viral assembly</p> Signup and view all the answers

    Why are some sites considered immune-privileged?

    <p>Because they are relatively hermetic to immune cells</p> Signup and view all the answers

    How do viruses first establish an infection in their hosts?

    <p>By overcoming physicochemical barriers</p> Signup and view all the answers

    What is one of the roles of hairs in the nostrils regarding viral infections?

    <p>Trap particulate matter</p> Signup and view all the answers

    Which of the following is NOT a molecular inhibitory molecule produced by the skin and mucosa against viruses?

    <p>Albumin</p> Signup and view all the answers

    What do complementary and other acute phase reactants do to virus particles in a soluble phase?

    <p>Have antimicrobial effects on viruses</p> Signup and view all the answers

    Which of the following is an example of an intrinsic factor that influences host susceptibility to viral infections according to the text?

    <p>Genes encoding immune responses</p> Signup and view all the answers

    In what way do some commensal microorganisms interfere with viral infections?

    <p>Modifying local pH or secreting inhibitors</p> Signup and view all the answers

    'Hepagglutinin and neuraminidase are examples of major antigenic determinants.' What happens if the cell was infected by strains from different host species?

    <p>Newly infected hosts will be ill-equipped to deal with new strains</p> Signup and view all the answers

    'Pathogenicity depends on the relationship between virus and host.' What does 'host susceptibility' refer to?

    <p>Function of inherent host factors in influencing pathogenicity</p> Signup and view all the answers

    What is the primary role of anatomical and mechanical barriers in host defense?

    <p>To prevent viral entry into the body</p> Signup and view all the answers

    How do keratinized cells of the skin contribute to preventing viral infections?

    <p>By making the skin impenetrable under normal circumstances</p> Signup and view all the answers

    What is one of the roles of epithelial ciliated cells in combating respiratory infections?

    <p>To transport trapped particulates out of the respiratory tract</p> Signup and view all the answers

    What is the main role of acute phase proteins mentioned in the text?

    <p>Promoting viral particles inactivation</p> Signup and view all the answers

    Why is apoptosis considered a preferred mode of cellular killing by the immune system?

    <p>It reduces the release of inflammatory DAMPs</p> Signup and view all the answers

    Which type of interferons are particularly important for initial viral containment?

    <p>Type I interferons (IFN-α &amp; IFN-ß)</p> Signup and view all the answers

    Why do NK cells readily kill cells that express little or no MHC-I?

    <p>When the NK cell KARs are not stimulated</p> Signup and view all the answers

    Which receptors play a crucial role in recognizing virally infected cells?

    <p>TLR3 and RLRs</p> Signup and view all the answers

    What is the effect of TLR7 and TLR8 activation in infected cells?

    <p>Recognition of viral ssRNA</p> Signup and view all the answers

    What is a key process triggered by IFN-α/ß or IFN-λ to eliminate infected cells?

    <p>Apoptosis</p> Signup and view all the answers

    Which pathway is involved in IFN-α/ß-mediated apoptosis through phosphorylation of eIF2?

    <p>PKR pathway</p> Signup and view all the answers

    What is the role of 2’-5’-oligo(A) synthetase/RNase L pathways upon IFN-α/ß stimulation?

    <p>Activate apoptosis</p> Signup and view all the answers

    Which gene products impede (-)ssRNA virus replication at different stages of the viral cycle?

    <p>Mx genes</p> Signup and view all the answers

    What is the function of some APOBEC proteins upon viral infection?

    <p>Cause viral genome degradation</p> Signup and view all the answers

    Which proteins act as inhibitors that hinder DNA virus replication within the nucleus?

    <p>PML, Sp100, &amp; Daxx</p> Signup and view all the answers

    What role does RNA silencing play in intrinsic cellular defenses against viruses?

    <p>Inhibit viral genome replication</p> Signup and view all the answers

    What do some ADAR1 induce upon viral infection?

    <p>RNA editing causing hypermutation</p> Signup and view all the answers

    What is one characteristic of MxA proteins specifically in influenza infections?

    <p>Interfere with uncoating and RNA transcription</p> Signup and view all the answers

    In what phase do some viruses exhibit the phenomenon of 'virus restriction' through mutational load and degradation of viral genomes?

    <p>Lyric phase</p> Signup and view all the answers

    What is the primary mechanism through which Mx genes impede (-)ssRNA virus replication?

    <p>Interference with RNA transcription</p> Signup and view all the answers

    Which mechanism of cell transformation characterizes Endemic Burkitt Lymphoma?

    <p>Insertional mutagenesis</p> Signup and view all the answers

    What chromosomal anomaly is responsible for constitutive expression of the c-myc gene in Endemic Burkitt Lymphoma?

    <p>Translocation of c-myc to chromosome 14</p> Signup and view all the answers

    Which accounts for the remaining 20% of Endemic Burkitt Lymphoma cases?

    <p>Translocation of c-myc to chromosome 8 or 22</p> Signup and view all the answers

    What is the most common mechanism by which viruses induce human carcinogenesis according to the text?

    <p>Insertional mutagenesis</p> Signup and view all the answers

    Which host factor influences pathogenicity by disrupting genes encoding immune responses?

    <p>TLR7 mutation</p> Signup and view all the answers

    What is a barrier that viruses need to overcome in the host's respiratory tract?

    <p>Epithelial ciliated cells</p> Signup and view all the answers

    Which factor can render some individuals more susceptible to certain viral infections?

    <p>Genetic makeup</p> Signup and view all the answers

    What is an inhibitory molecule produced by the skin and mucosa against viruses?

    <p>Secretory leukocyte proteinase inhibitor</p> Signup and view all the answers

    Which immune response mechanism involves serum proteins with antimicrobial effects?

    <p>Innate immune responses</p> Signup and view all the answers

    What is a common anatomical barrier that makes the skin virtually impenetrable?

    <p>Keratinized cells</p> Signup and view all the answers

    Which phase involves viral particles being susceptible to serum proteins like mannan-binding lectins?

    <p>Soluble phase</p> Signup and view all the answers

    Which mechanism helps remove particulates from the respiratory tract?

    <p>Epithelial ciliated cells transport particles up the tract</p> Signup and view all the answers

    What type of barrier is made up of functional or structural components?

    <p>Anatomical barriers</p> Signup and view all the answers

    Which factor can influence viral pathogenicity in a host?

    <p>Host general health</p> Signup and view all the answers

    What is the role of p21cip in cell cycling in the context of HPV E7 protein?

    <p>Inhibits G1 cyclin-Cdk complex</p> Signup and view all the answers

    Which viral protein is responsible for sequestering pRb and disrupting pRb-E2f complexes in Cervical/Anal/Oropharyngeal Carcinoma?

    <p>HPV E7 protein</p> Signup and view all the answers

    How does the HPV E6 protein affect p53 in the context of carcinogenesis?

    <p>Sends p53 for proteasomal degradation</p> Signup and view all the answers

    What is a characteristic effect of HBV X protein on cellular genes in Hepatocellular Carcinoma?

    <p>Activation of protooncogenes</p> Signup and view all the answers

    How do virokines contribute to tumorigenesis in Kaposi Sarcoma?

    <p>Stimulate cell growth</p> Signup and view all the answers

    What is the effect of viroceptors encoded by large DNA viruses on host cytokines?

    <p>Counteract the host's immune response</p> Signup and view all the answers

    Which mechanism leads to increased probabilities of DNA mutations in Hepatocellular Carcinoma?

    <p>Greater hepatocyte proliferation due to liver inflammation</p> Signup and view all the answers

    What is the primary role of virokines in viral pathogenesis?

    <p>Counteract host antiviral mechanisms</p> Signup and view all the answers

    What is the result of increased levels of p53 in the cell nucleus due to HPV E6 protein actions?

    <p>Increased DNA damage</p> Signup and view all the answers

    How does HBV infection contribute to hepatocyte DNA mutations over time?

    <p>By increasing probabilities of DNA mutations with increased hepatocyte proliferation</p> Signup and view all the answers

    How do large DNA viruses like Herpesviridae counteract host immune responses?

    <p>Dampen host immune responses by sequestering cytokines and chemokines using viroceptors</p> Signup and view all the answers

    Which type of proteins are mostly generated by the liver in response to macrophage proinflammatory cytokines and serve to promote viral particles inactivation?

    <p>Acute phase proteins</p> Signup and view all the answers

    Cells undergoing stress, such as infection, react by expressing danger-associated molecular patterns (DAMPs), which induce an inflammatory process if the cell dies via:

    <p>Necrosis</p> Signup and view all the answers

    Which type of cells will readily kill cells that express little or no MHC-I?

    <p>NK cells</p> Signup and view all the answers

    Which type of interferons are particularly important for the initial containment of viral infections?

    <p>Type I interferons only</p> Signup and view all the answers

    Which receptors recognize dsRNA in infected cells, triggering the expression of type I interferons?

    <p>TLR3 and RLRs</p> Signup and view all the answers

    What happens when infected cells express MHC-I-like molecules such as MICA and MICB on their surface?

    <p>They trigger NK cell killing mechanisms</p> Signup and view all the answers

    What leads to the up-regulation of Fas surface expression in stressed cells?

    <p>Stress responses</p> Signup and view all the answers

    'Type I IFNs stimulate the infected cell (autocrine) AND neighboring cells (paracrine) to express a set of hundreds of IFN-inducible genes' - This describes:

    <p>'Positive feedback loop'</p> Signup and view all the answers

    'Virally infected cells have the capacity to recognize dsRNA' - Which cellular receptors play a role in this recognition process?

    <p>'TLR3 and RLRs'</p> Signup and view all the answers

    'Fas surface expression is up-regulated in stressed cells' - What role does this up-regulation play in the immune response against infections?

    <p>'Promote apoptosis'</p> Signup and view all the answers

    'What is the primary role of autophagy in combating viral infections?'

    <p>'Eliminating intracellular pathogens'</p> Signup and view all the answers

    'Why is apoptosis considered a preferred mode of cellular killing by the immune system?'

    <p>'It avoids release of danger signals'</p> Signup and view all the answers

    What is the main consequence of the activation of PKR upon type I IFN stimulation?

    <p>Cellular apoptosis</p> Signup and view all the answers

    Which pathway triggered by IFN-α/ß stimulation leads to degradation of cellular RNA?

    <p>2’-5’-oligo(A) synthetase pathway</p> Signup and view all the answers

    What is the primary role of Mx genes in combating viral infections?

    <p>Impede viral replication</p> Signup and view all the answers

    Which proteins are examples of APOBEC proteins that cause virus restriction?

    <p>APOBEC3A and APOBEC3G</p> Signup and view all the answers

    What is the impact of activating RNase L upon IFN-α/ß stimulation?

    <p>Cell death through apoptosis</p> Signup and view all the answers

    Which proteins impede (-)ssRNA virus replication by interfering with viral nucleoprotein uncoating and RNA transcription?

    <p>MxA and AID</p> Signup and view all the answers

    What is the main impact of MxA proteins on influenza viruses?

    <p>Inhibiting viral uncoating and RNA transcription</p> Signup and view all the answers

    Which cellular defense mechanisms act as DNA transcription inhibitors to hinder DNA virus replication?

    <p>(PML, Sp100, &amp; Daxx)</p> Signup and view all the answers

    What is the driving force behind genetic drift in viruses?

    <p>Proofreading capacity of viral polymerases</p> Signup and view all the answers

    How do some viruses evade immune responses by altering NK cell cytotoxicity?

    <p>Expressing cell surface molecules</p> Signup and view all the answers

    What is the consequence of reduced class I-mediated CD8 cell cytotoxicity by viruses?

    <p>Increased viral replication</p> Signup and view all the answers

    How do some enveloped viruses increase virulence?

    <p>Incorporating host molecules into their membranes</p> Signup and view all the answers

    Which characteristic of RNA viruses contributes to the frequent introduction of mutations?

    <p>Segmented genome</p> Signup and view all the answers

    How do some viruses modulate the host cell's antigen presentation capability?

    <p>Promoting MHC re-internalization</p> Signup and view all the answers

    Why can mutations in viral epitopes lead to the generation of escape mutants?

    <p>Altered antigenicity of viral epitopes</p> Signup and view all the answers

    How do some viruses increase infectivity through alterations in their membranes?

    <p>Incorporating host molecules</p> Signup and view all the answers

    What is the role of caspase 1 in the activation of IL-18?

    <p>It cleaves pro-IL-18 into its biologically active form.</p> Signup and view all the answers

    How does IL-18 differ from other proinflammatory cytokines like IL-1β, IL-6, and TNF-α?

    <p>It does not induce fever or stimulate prostaglandin or leukotriene expression.</p> Signup and view all the answers

    In viral infections, which cells does IL-18 work in tandem with to activate NK cells and macrophages?

    <p>IL-12</p> Signup and view all the answers

    What is the primary function of IL-18 and IL-12 in acquired responses?

    <p>To promote the activation and differentiation of T lymphocytes</p> Signup and view all the answers

    Which immunoglobulin isotype is more efficient for antibody-dependent cell cytotoxicity (ADCC)?

    <p>IgG2a</p> Signup and view all the answers

    Among the following cells, which one is NOT mentioned as engaging IgG-bound infected cells in antibody-dependent cell cytotoxicity?

    <p>B cells</p> Signup and view all the answers

    Which immunoglobulin isotype is highlighted as being better at activating complement?

    <p>IgG2b</p> Signup and view all the answers

    In the context of specific functions, which immunoglobulin isotype is better suited for neutralization?

    <p>IgG3</p> Signup and view all the answers

    Which cells play a significant role in controlling viral infections through IFN-γ and TNF-α expression at the cell-cell interface?

    <p>Cytotoxic T lymphocytes</p> Signup and view all the answers

    What is the main action of the vIL-18BP expressed by some viruses?

    <p>Dampening the host's immune response by binding to IL-18</p> Signup and view all the answers

    Which receptors are primarily responsible for recognizing viral infections in macrophages and dendritic cells?

    <p>Toll-like receptors (TLRs)</p> Signup and view all the answers

    What is the main function of immature dendritic cells at the site of infection?

    <p>Take up foreign material and let themselves be infected by viruses</p> Signup and view all the answers

    Which pathway is another important virus-detecting system besides Toll-like receptors in macrophages?

    <p>RIG-1 pathway</p> Signup and view all the answers

    What is the outcome of IL-12 secretion by macrophages and dendritic cells in response to viral infections?

    <p>Activation of NK cells and IFN-γ secretion</p> Signup and view all the answers

    What causes immature dendritic cells to mature as they migrate to secondary lymphoid tissues?

    <p>Cytokine milieu at the site of infection</p> Signup and view all the answers

    Which subset of macrophages is activated following PAMP-PRR interaction in viral infections?

    <p>Innately activated macrophages</p> Signup and view all the answers

    What is the primary purpose of pathogen engulfment by macrophages and dendritic cells at the site of infection?

    <p>MHC-II-restricted Ag presentation</p> Signup and view all the answers

    What happens when immature dendritic cells and macrophages migrate to secondary lymphoid tissues?

    <p>Present pathogen-derived antigen to T lymphocytes</p> Signup and view all the answers

    What is the main function of monocyte-derived phagocytic cells in controlling viral infections?

    <p>Destroy it on site</p> Signup and view all the answers

    How do some viruses counteract host immune responses?

    <p>Express viroceptors that dampen host's immune response</p> Signup and view all the answers

    Which proteasomal subunits are replaced by the LMP2, LMP7, and MECL-1 subunits under the influence of IFN-γ?

    <p>ß1, ß5, and ß2</p> Signup and view all the answers

    What transformation occurs to immature dendritic cells under the influence of IFN-γ?

    <p>They become mature dendritic cells</p> Signup and view all the answers

    Which cytokine is produced when a naïve CD4+ lymphocyte is engaged by a pAPC in an IL-12-rich environment?

    <p>IL-12</p> Signup and view all the answers

    What is the outcome of TH1 cell activation?

    <p>IFN-γ secretion</p> Signup and view all the answers

    Which subset of macrophages secretes IL-10 to shut off the immune response?

    <p>Adaptively deactivated macrophages</p> Signup and view all the answers

    In the context of viral infection containment, what is the main adaptive mechanism for killing virally-infected cells?

    <p>CTL-mediated MHC-I-dependent killing</p> Signup and view all the answers

    What is the primary function of IFN-γ-producing CD4+, CD8+, and NK cells at the site of infection?

    <p>Activating macrophage-killing mechanisms</p> Signup and view all the answers

    What is the role of memory CD4+ and CD8+ T lymphocytes in subsequent infections with the same pathogen?

    <p>Contributing to anamnestic response</p> Signup and view all the answers

    What is the function of IL-10 secreted by specific macrophages and Treg cells after infection containment?

    <p>Inhibiting unnecessary immune response</p> Signup and view all the answers

    What is unique about CD8+ T lymphocyte activation requirements?

    <p>It requires MHC-I-restricted antigen presentation</p> Signup and view all the answers

    What leads to the establishment of the TH1 response through inter-stimulation and positive feedback mechanisms?

    <p>Interactions between T lymphocytes, macrophages, and NK cells</p> Signup and view all the answers

    What triggers the differentiation of a TH1 cell producing key cytokines like IL-2 and IFN-γ?

    <p>Engagement by a pAPC in an IL-12-rich environment</p> Signup and view all the answers

    What is the main role of activated CD8+ T lymphocytes?

    <p>Destroying virally infected cells</p> Signup and view all the answers

    Which molecule is involved in transferring peptides to the endoplasmic reticulum for loading onto MHC-I molecules?

    <p>TAP1/TAP2</p> Signup and view all the answers

    In CD8 T lymphocyte activation, what is the role of CD4+ T lymphocyte help?

    <p>Increasing CD86 co-stimulatory molecule expression</p> Signup and view all the answers

    Which cells differentiate into TFH1 cells that help in B cell activation?

    <p>CD4+ T lymphocytes</p> Signup and view all the answers

    How do antibodies created by B cells help combat viruses?

    <p>Tagging infected cells for destruction</p> Signup and view all the answers

    Which process involves B cells capturing viral antigen via their BCR?

    <p>Endocytosis</p> Signup and view all the answers

    What role do TFH1 cells play in secondary lymphoid tissues?

    <p>Helping B cells differentiate into plasma cells and memory B cells</p> Signup and view all the answers

    In viral spread, what is the function of follicular dendritic cells?

    <p>Transferring antigen to B cells</p> Signup and view all the answers

    How does IFN-γ influence the TH1 response?

    <p>It amplifies the TH1 response to increase FasL levels</p> Signup and view all the answers

    What is the primary function of APOBEC expression in combatting viruses?

    <p>Causing mutation in viral DNA to limit infection</p> Signup and view all the answers

    Why does CD8 T lymphocyte activation require a higher threshold of CD86 co-stimulation compared to CD4 T lymphocytes?

    <p>CD8 T lymphocytes have a higher destructive potential</p> Signup and view all the answers

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