longquiz

• What is the immune response to viral infection?

  It involves recognizing and processing viruses
• Why are viruses considered obligate intracellular organisms?

  They require host cells to survive
• What happens when a virus first encounters its host species?

  It may cause lethal diseases
• What characterizes infections with poor virus-host adaptation?

  They tend to be acute and severe
• Name one virus that causes acute and severe infections.

  Rabies
• What is a characteristic of infections with better virus-host adaptation?

  Mortality may not be high
• Why is vaccination against certain viruses often unsuccessful?

  Viruses may change and evade the immune system
• What is the structure of a virion?

  It consists of nucleic acid core and protein layer
• What is the role of capsomeres in a virus?

  They form the capsid protein layer
• How do antibodies function against viruses?

  They block cell invasion and stimulate phagocytosis
• What is the first step in viral replication?

  Attachment to a surface receptor
• What is the role of interferons in viral resistance?

  They signal cells to develop resistance
• What do virus-infected leukocytes produce?

  Large amounts of IFN-α
• What is the major source of IFN-γ?

  Antigen-stimulated T cells
• How do antibodies neutralize viruses?

  By preventing cell invasion and causing clumping
• What is the significance of IgG in serum?

  It is the most significant immunoglobulin
• What is the role of cytotoxic T cells?

  They recognize and kill infected cells
• What is antigenic variation?

  A mechanism viruses use to evade destruction
• What is antigenic drift in influenza viruses?

  Gradual changes in hemagglutinins and neuraminidase
• What is antigenic shift?

  A sudden major genetic change in viruses
• How do viruses block antiviral interferons?

  By inhibiting T cell-mediated cytotoxicity
• What is the relationship between stress and viral diseases?

  Stress may lead to immunosuppression
• What are the mechanisms of antibody-mediated immunity against viruses?

  • Blocking virion adsorption to target cells
  • Stimulating phagocytosis of viruses
  • Triggering complement-mediated virolysis
  • Causing viral clumping
• What are the innate immunity responses to viral infections?

  • Interferons play a key role
  • Lysozyme and intestinal enzymes can destroy viruses
  • Infected cells may undergo apoptosis
  • Leukocytes and NK cells contribute to the response
• What are the key points about the evasion of the immune response by viruses?

  • Antigenic variation is a common strategy
  • Influenza viruses undergo antigenic drift and shift
  • Viruses can inhibit T cell-mediated cytotoxicity
  • Persistent viruses may boost immune responses
• What are the roles of different immunoglobulins in viral immunity?

  • IgG: most significant in serum
  • IgM: qualitatively superior
  • IgA: found in secretions
• What is the significance of immunological memory to viruses?

  • Antibodies may persist for years
  • Memory can vary in duration
  • Important for long-term immunity
• What is the focus of Module 8 in Veterinary Immunology?

  Immunity to bacterial and fungal infection
• What are the learning outcomes of this module?

  Describe immune response and discuss recognition mechanisms
• Why can most microorganisms in the environment not cause disease in animals?

  Due to innate and acquired immune systems
• What factors influence the development of diseases in animals?

  Host response, damaged tissues, bacterial location, virulence
• What are the two components of antimicrobial immunity?

  Innate response and sustained adaptive response
• How do TLRs contribute to the immune response?

  They induce inflammation, cytokine release, and complement activation
• What are the five basic mechanisms of the acquired immune response to bacterial infections?

  Neutralization, killing by antibodies, opsonization, intracellular destruction, direct killing
• What is the role of antibodies in combating bacterial infections?

  • Neutralize toxins or enzymes
  • Kill bacteria with complement
  • Opsonize bacteria for phagocytosis
  • Activate macrophages for destruction
  • Directly kill bacteria via cytotoxic T cells
• How does the immune response deal with toxigenic bacteria?

  It eliminates bacteria and neutralizes their toxins
• What happens when a toxin binds to its receptors on target cells?

  Antibodies are ineffective in reversing the combination
• How is immunity to invasive bacteria usually mediated?

  By antibodies against surface antigens
• What enhances phagocytosis of bacteria?

  Opsonization by antibodies and complement
• What is the role of C3b in bacterial immunity?

  It binds to bacterial surfaces for complement activation