Immune response to viruses Presented by Yoavanit Srivaro, MD. December 11, 2015

1. Immune response to viruses
Yoavanit Srivaro M.D.

2. Outlines
• Definition and Properties of a Virus
• Viral replication
• Innate immune response to viral infection
• Adaptive immune response to viral infection
• Immune Evasion by Viruses

3. Outlines
• Definition and Properties of a Virus
• Viral replication
• Innate immune response to viral infection
• Adaptive immune response to viral infection
• Immune Evasion by Viruses

4. Definition and Properties of a Virus
• Filterable agents
• Obligate intracellular parasites
• Can not make energy/proteins without host cell
Murray PR, Rosenthal KS, Pfaller MA, editors. Medical microbiology. 8th ed. Philadelphia: Elsevier Saunder; 2014.

5. Definition and Properties of a Virus
• Viral genomes may be RNA or DNA
• Viruses have a naked capsid or an envelope
morphology
• Viral components are assembled and do not
replicate by “division.”
Murray PR, Rosenthal KS, Pfaller MA, editors. Medical microbiology. 8th ed. Philadelphia: Elsevier Saunder; 2014.

6. FIGURE 36-1 Components of the basic virion.
Murray PR, Rosenthal KS, Pfaller MA, editors. Medical microbiology. 8th ed. Philadelphia: Elsevier Saunder; 2014.

7. FIGURE 36-1 Components of the basic virion.
Murray PR, Rosenthal KS, Pfaller MA, editors. Medical microbiology. 8th ed. Philadelphia: Elsevier Saunder; 2014.

8. FIGURE 36-1 Components of the basic virion.
Murray PR, Rosenthal KS, Pfaller MA, editors. Medical microbiology. 8th ed. Philadelphia: Elsevier Saunder; 2014.

9. FIGURE 36-1 Components of the basic virion.
Murray PR, Rosenthal KS, Pfaller MA, editors. Medical microbiology. 8th ed. Philadelphia: Elsevier Saunder; 2014.

10. FIGURE 36-1 Components of the basic virion.
Murray PR, Rosenthal KS, Pfaller MA, editors. Medical microbiology. 8th ed. Philadelphia: Elsevier Saunder; 2014.

11. FIGURE 36-4 Virion structure.
Murray PR, Rosenthal KS, Pfaller MA, editors. Medical microbiology. 8th ed. Philadelphia: Elsevier Saunder; 2014.

13. FIGURE 36-1 Components of the basic virion.
Murray PR, Rosenthal KS, Pfaller MA, editors. Medical microbiology. 8th ed. Philadelphia: Elsevier Saunder; 2014.

14. FIGURE 36-1 Components of the basic virion.
Murray PR, Rosenthal KS, Pfaller MA, editors. Medical microbiology. 8th ed. Philadelphia: Elsevier Saunder; 2014.

15. FIGURE 36-1 Components of the basic virion.
Murray PR, Rosenthal KS, Pfaller MA, editors. Medical microbiology. 8th ed. Philadelphia: Elsevier Saunder; 2014.

16. FIGURE 36-4 Virion structure.

17. FIGURE 36-4 Virion structure.
Murray PR, Rosenthal KS, Pfaller MA, editors. Medical microbiology. 8th ed. Philadelphia: Elsevier Saunder; 2014.

18. FIGURE 36-4 Virion structure.
Murray PR, Rosenthal KS, Pfaller MA, editors. Medical microbiology. 8th ed. Philadelphia: Elsevier Saunder; 2014.

20. Outlines
• Definition and Properties of a Virus
• Viral replication
• Innate immune response to viral infection
• Adaptive immune response to viral infection
• Immune Evasion by Viruses

21. FIGURE 36-8 A general scheme of viral replication
Peakman M, Vergani D, editors. Basic and Clinical Immunology. 2nd ed. Philadelphia: Elsevier Saunders; 2009.

22. FIGURE 36-8 A general scheme of viral replication
Peakman M, Vergani D, editors. Basic and Clinical Immunology. 2nd ed. Philadelphia: Elsevier Saunders; 2009.

23. Virus Receptor
Epstein-Barr virus Complement receptor 2 (CR2)
Influenza virus Sialic residue on cell surface
glycoprotein
Rhinovirus Intracellular adhesion molecule:
ICAMs
Vaccinia virus Epidermal growth factor receptor
Cellular receptor for viruses entry

24. FIGURE 36-8 A general scheme of viral replication
Peakman M, Vergani D, editors. Basic and Clinical Immunology. 2nd ed. Philadelphia: Elsevier Saunders; 2009.

25. FIGURE 36-8 A general scheme of viral replication
Peakman M, Vergani D, editors. Basic and Clinical Immunology. 2nd ed. Philadelphia: Elsevier Saunders; 2009.

26. FIGURE 36-8 A general scheme of viral replication
Peakman M, Vergani D, editors. Basic and Clinical Immunology. 2nd ed. Philadelphia: Elsevier Saunders; 2009.

27. FIGURE 36-8 A general scheme of viral replication
Peakman M, Vergani D, editors. Basic and Clinical Immunology. 2nd ed. Philadelphia: Elsevier Saunders; 2009.

28. FIGURE 36-8 A general scheme of viral replication
Peakman M, Vergani D, editors. Basic and Clinical Immunology. 2nd ed. Philadelphia: Elsevier Saunders; 2009.

29. FIGURE 36-8 A general scheme of viral replication
Peakman M, Vergani D, editors. Basic and Clinical Immunology. 2nd ed. Philadelphia: Elsevier Saunders; 2009.

30. FIGURE 36-8 A general scheme of viral replication
Peakman M, Vergani D, editors. Basic and Clinical Immunology. 2nd ed. Philadelphia: Elsevier Saunders; 2009.

31. Scott N. Mueller BTR. Immune responses to viruses. In: Rich RR, Fleisher TA, William T. Shearer HW, Jr. S, Frew AJ, Weyand CM, editors. Clinical
immunology principle and practice. 3rd ed. Philadelphia: Mosby Elsevier 2008. p. 421-31.

32. Outlines
• Definition and Properties of a Virus
• Viral replication
• Innate immune response to viral infection
• Adaptive immune response to viral infection
• Immune Evasion by Viruses

33. Innate immune response
to viral infection
• Epithelial barrier
• Early non-specific or innate immune
– Interferon (IFN)
• Type I IFNs (IFN α and IFN β)
• Type II IFN (IFN γ)
– Natural killer cells
– Macrophages
Borrow P, Nash AA. Immunity to viruses. In: Male D, Brostoff J, Roth D, Roitt I, editors. Immunology. 8th ed. Philadelphia: Elsevier Saunders; 2013.
p. 211-22.
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

34. Innate immune response
to viral infection
• Epithelial barrier
• Early non-specific or innate immune
– Interferon (IFN)
• Type I IFNs (IFN α and IFN β)
• Type II IFN (IFN γ)
– Natural killer cells
– Macrophages
Borrow P, Nash AA. Immunity to viruses. In: Male D, Brostoff J, Roth D, Roitt I, editors. Immunology. 8th ed. Philadelphia: Elsevier Saunders; 2013.
p. 211-22.
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

35. FIGURE 4-5 Epithelial barriers.
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

36. FIGURE 4-5 Epithelial barriers.
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

37. Innate immune response
to viral infection
• Epithelial barrier
• Early non-specific or innate immune
– Interferon (IFN)
• Type I IFNs (IFN α and IFN β)
• Type II IFN (IFN γ)
– Natural killer cells
– Macrophages
Borrow P, Nash AA. Immunity to viruses. In: Male D, Brostoff J, Roth D, Roitt I, editors. Immunology. 8th ed. Philadelphia: Elsevier Saunders; 2013.
p. 211-22.
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

38. Type I interferons
• IFN-α is produced by
- Plasmacytoid dendritic cells
- Mononuclear phagocytes
• IFN-β is produced by many cell types
Interferon: interfere with viral infection
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

39. FIGURE 13.1 Pathways by which type I IFN production
Plasmacytoid DCs
• Produce high levels
of type I IFN
• Without themselves
becoming infected
Borrow P, Nash AA. Immunity to viruses. In: Male D, Brostoff J, Roth D, Roitt I, editors. Immunology. 8th ed. Philadelphia: Elsevier Saunders; 2013.
p. 211-22.

40. FIGURE 4-16 Mechanisms of induction of type I interferons by viruses
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

41. FIGURE 4-16 Mechanisms of induction of type I interferons by viruses
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

42. FIGURE 4-16 Mechanisms of induction of type I interferons by viruses
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

43. FIGURE 4-16 Mechanisms of induction of type I interferons by viruses
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

44. FIGURE 4-16 Mechanisms of induction of type I interferons by viruses
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

45. FIGURE 4-17 Biologic actions of type I interferons
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

46. FIGURE 4-17 Biologic actions of type I interferons
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

47. FIGURE 4-17 Biologic actions of type I interferons
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

48. FIGURE 4-17 Biologic actions of type I interferons
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

49. FIGURE 4-17 Biologic actions of type I interferons

50. FIGURE 4-17 Biologic actions of type I interferons
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

51. FIGURE 4-17 Biologic actions of type I interferons
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed.Philadelphia Elsevier Saunders:;2015.

52. Innate immune response
to viral infection
• Epithelial barrier
• Early non-specific or innate immune
– Interferon (IFN)
• Type I IFNs (IFN α and IFN β)
• Type II IFN (IFN γ)
– Natural killer cells
– Macrophages

53. FIGURE 4-7 Functions of NK cells
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed.Philadelphia Elsevier Saunders:;2015.
Important mechanism of immunity against viruses early in the course
of infection.

54. Innate immune response
to viral infection
• Epithelial barrier
• Early non-specific or innate immune
– Interferon (IFN)
• Type I IFNs (IFN α and IFN β)
• Type II IFN (IFN γ)
– Natural killer cells
– Macrophages

55. Macrophages
• Phagocytosis of virus and virus-infected cells;
• Killing of virus-infected cells; and
• Production of antiviral molecules
: TNFα, nitric oxide, and IFNα.
Borrow P, Nash AA. Immunity to viruses. In: Male D, Brostoff J, Roth D, Roitt I, editors. Immunology. 8th ed. Philadelphia: Elsevier Saunders; 2013.
p. 211-22.

56. Adaptive immune response
to viral infection
• Antiviral antibodies
• Cytotoxic T lymphocytes (CTLs)
• Helper T (Th) cells
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.
Borrow P, Nash AA. Immunity to viruses. In: Male D, Brostoff J, Roth D, Roitt I, editors. Immunology. 8th ed. Philadelphia: Elsevier Saunders; 2013.
p. 211-22.

57. Adaptive immune response
to viral infection
• Antiviral antibodies
• Cytotoxic T lymphocytes (CTLs)
• Helper T (Th) cells
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.
Borrow P, Nash AA. Immunity to viruses. In: Male D, Brostoff J, Roth D, Roitt I, editors. Immunology. 8th ed. Philadelphia: Elsevier Saunders; 2013.
p. 211-22.

58. Antiviral antibodies
• Secretory IgA: neutralizing antibody
- Respiratory tract
- Intestinal tract
• IgG
- ADCC
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.
Borrow P, Nash AA. Immunity to viruses. In: Male D, Brostoff J, Roth D, Roitt I, editors. Immunology. 8th ed. Philadelphia: Elsevier Saunders; 2013.
p. 211-22.

59. Antiviral antibodies
• Secretory IgA: neutralizing antibody
- Respiratory tract
- Intestinal tract
• IgG
- ADCC
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.
Borrow P, Nash AA. Immunity to viruses. In: Male D, Brostoff J, Roth D, Roitt I, editors. Immunology. 8th ed. Philadelphia: Elsevier Saunders; 2013.
p. 211-22.

60. Fig. 13.6 Effector mechanisms by which adaptive responses combat virus replication
Borrow P, Nash AA. Immunity to viruses. In: Male D, Brostoff J, Roth D, Roitt I, editors. Immunology. 8th ed. Philadelphia: Elsevier Saunders; 2013.
p. 211-22.
1. Blocks binding to cell
2. Blocks entry into cell

61. Fig. 13.6 Effector mechanisms by which adaptive responses combat virus replication
Borrow P, Nash AA. Immunity to viruses. In: Male D, Brostoff J, Roth D, Roitt I, editors. Immunology. 8th ed. Philadelphia: Elsevier Saunders; 2013.
p. 211-22.
1. Activate membrane attack complex lysis
2. Opsonization

62. Fig. 13.6 Effector mechanisms by which adaptive responses combat virus replication
Borrow P, Nash AA. Immunity to viruses. In: Male D, Brostoff J, Roth D, Roitt I, editors. Immunology. 8th ed. Philadelphia: Elsevier Saunders; 2013.
p. 211-22.
Antibody bound to infected cells ADCC

63. Adaptive immune response
to viral infection
• Antiviral antibodies
• Cytotoxic T lymphocytes (CTLs)
• Helper T (Th) cells
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.
Borrow P, Nash AA. Immunity to viruses. In: Male D, Brostoff J, Roth D, Roitt I, editors. Immunology. 8th ed. Philadelphia: Elsevier Saunders; 2013.
p. 211-22.

64. FIGURE 16-7 Adaptive immune responses against viruses.
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

65. FIGURE 11-6 Mechanisms of CTL-mediated killing of target cells..
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

66. FIGURE 11-6 Mechanisms of CTL-mediated killing of target cells..
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

67. FIGURE 11-6 Mechanisms of CTL-mediated killing of target cells..
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

68. FIGURE 11-6 Mechanisms of CTL-mediated killing of target cells..
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

69. Fig. 13.6 Effector mechanisms by which adaptive responses combat virus replication
Borrow P, Nash AA. Immunity to viruses. In: Male D, Brostoff J, Roth D, Roitt I, editors. Immunology. 8th ed. Philadelphia: Elsevier Saunders; 2013.
p. 211-22.

70. Adaptive immune response
to viral infection
• Antiviral antibodies
• Cytotoxic T lymphocytes (CTLs)
• Helper T (Th) cells
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.
Borrow P, Nash AA. Immunity to viruses. In: Male D, Brostoff J, Roth D, Roitt I, editors. Immunology. 8th ed. Philadelphia: Elsevier Saunders; 2013.
p. 211-22.

71. Helper T (Th) cells
• CD4+ T cell-derived IL-2: CD8+ T cell growth factor
• CD4+ T cell-derived chemokines: recruit CD8+ T to
site of infection
• CD4+ T cells secrete IFNγ and TNFα to recruit and
activate macrophages
Borrow P, Nash AA. Immunity to viruses. In: Male D, Brostoff J, Roth D, Roitt I, editors. Immunology. 8th ed. Philadelphia: Elsevier Saunders; 2013.
p. 211-22.

72. Helper T (Th) cells
• CD4+ T cell-derived IL-2: CD8+ T cell growth factor
• CD4+ T cell-derived chemokines: recruit CD8+ T to
site of infection
• CD4+ T cells secrete IFNγ and TNFα to recruit and
activate macrophages
Borrow P, Nash AA. Immunity to viruses. In: Male D, Brostoff J, Roth D, Roitt I, editors. Immunology. 8th ed. Philadelphia: Elsevier Saunders; 2013.
p. 211-22.

73. Helper T (Th) cells
• CD4+ T cell-derived IL-2: CD8+ T cell growth factor
• CD4+ T cell-derived chemokines: recruit CD8+ T to
site of infection
• CD4+ T cells secrete IFNγ and TNFα to recruit and
activate macrophages
Borrow P, Nash AA. Immunity to viruses. In: Male D, Brostoff J, Roth D, Roitt I, editors. Immunology. 8th ed. Philadelphia: Elsevier Saunders; 2013.
p. 211-22.

74. Fig. 13.6 Effector mechanisms by which adaptive responses combat virus replication
Borrow P, Nash AA. Immunity to viruses. In: Male D, Brostoff J, Roth D, Roitt I, editors. Immunology. 8th ed. Philadelphia: Elsevier Saunders; 2013.
p. 211-22.

75. FIGURE 16-7 Innate and adaptive immune responses against viruses.
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

76. FIGURE 16-7 Innate and adaptive immune responses against viruses.
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

77. FIGURE 16-7 Innate and adaptive immune responses against viruses.
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

78. FIGURE 16-7 Innate and adaptive immune responses against viruses.
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

79. Outlines
• Definition and Properties of a Virus
• Viral replication
• Innate immune response to viral infection
• Adaptive immune response to viral infection
• Immune Evasion by Viruses

80. Mechanism of Immune Evasion Examples
Antigenic variation Influenza, rhinovirus, HIV
Inhibition of antigen processing
Blockade of TAP transporter
Removal of class I molecules
from the ER
Herpes simplex virus (HSV)
Cytomegalovirus (CMV)
Production of “decoy” MHC
molecules to inhibit NK cells
Cytomegalovirus (murine)
Production of cytokine receptor
homologues
Vaccinia, poxviruses (IL-1, IFN-γ)
Cytomegalovirus (chemokine)
TABLE 16-3 Mechanisms of Immune Evasion by Viruses
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

81. Figure 11-29
Biochemistry Sixth Edition
2007 W.H> Freeman and Company
Influenza Virus

82. Figure 11-29
Biochemistry Sixth Edition
2007 W.H> Freeman and Company
Influenza Virus

83. Borrow P, Nash AA. Immunity to viruses. In: Male D, Brostoff J, Roth D, Roitt I, editors. Immunology. 8th ed. Philadelphia: Elsevier Saunders; 2013.
p. 211-22.

84. Borrow P, Nash AA. Immunity to viruses. In: Male D, Brostoff J, Roth D, Roitt I, editors. Immunology. 8th ed. Philadelphia: Elsevier Saunders; 2013.
p. 211-22.

85. FIGURE 16-8 Generation of new influenza virus strainsby genetic recombination
(antigenic shift).
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

86. Mechanism of Immune Evasion Examples
Antigenic variation Influenza, rhinovirus, HIV
Inhibition of antigen processing
Blockade of TAP transporter
Removal of class I molecules
from the ER
Herpes simplex virus (HSV)
Cytomegalovirus (CMV)
Production of “decoy” MHC
molecules to inhibit NK cells
Cytomegalovirus (murine)
Production of cytokine receptor
homologues
Vaccinia, poxviruses (IL-1, IFN-γ)
Cytomegalovirus (chemokine)
TABLE 16-3 Mechanisms of Immune Evasion by Viruses
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

87. Mechanism of Immune Evasion Examples
Antigenic variation Influenza, rhinovirus, HIV
Inhibition of antigen processing
Blockade of TAP transporter
Removal of class I molecules
from the ER
Herpes simplex virus (HSV)
Cytomegalovirus (CMV)
Production of “decoy” MHC
molecules to inhibit NK cells
Cytomegalovirus (murine)
Production of cytokine receptor
homologues
Vaccinia, poxviruses (IL-1, IFN-γ)
Cytomegalovirus (chemokine)
TABLE 16-3 Mechanisms of Immune Evasion by Viruses
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

88. FIGURE16-9 Mechanisms by which viruses inhibit antigen processing & presentation.
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

89. FIGURE16-9 Mechanisms by which viruses inhibit antigen processing & presentation.
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

90. FIGURE16-9 Mechanisms by which viruses inhibit antigen processing & presentation.
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

91. FIGURE16-9 Mechanisms by which viruses inhibit antigen processing & presentation.
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

92. FIGURE16-9 Mechanisms by which viruses inhibit antigen processing & presentation.
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

93. Mechanism of Immune Evasion Examples
Antigenic variation Influenza, rhinovirus, HIV
Inhibition of antigen processing
Blockade of TAP transporter
Removal of class I molecules
from the ER
Herpes simplex virus (HSV)
Cytomegalovirus (CMV)
Production of “decoy” MHC
molecules to inhibit NK cells
Cytomegalovirus (murine)
Production of cytokine receptor
homologues
Vaccinia, poxviruses (IL-1, IFN-γ)
Cytomegalovirus (chemokine)
TABLE 16-3 Mechanisms of Immune Evasion by Viruses
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

94. Mechanism of Immune Evasion Examples
Production of immunosuppressive
cytokine
Epstein-Barr (IL-10)
Infection and death or functional
impairment of immune cells
HIV
Inhibition of complement
activation
Recruitment of factor H
Incorporation of CD59 in viral envelope
HIV
HIV, vaccinia, human CMV
Inhibition of innate immunity
Inhibition of access to RIG-I
RNA sensor
Inhibition of PKR (signaling by
IFN receptor
Vaccinia, HIV
HIV, HCV, HSV, polio
TABLE 16-3 Mechanisms of Immune Evasion by Viruses
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

95. Mechanism of Immune Evasion Examples
Production of immunosuppressive
cytokine
Epstein-Barr (IL-10)
Infection and death or functional
impairment of immune cells
HIV
Inhibition of complement
activation
Recruitment of factor H
Incorporation of CD59 in viral envelope
HIV
HIV, vaccinia, human CMV
Inhibition of innate immunity
Inhibition of access to RIG-I
RNA sensor
Inhibition of PKR (signaling by
IFN receptor
Vaccinia, HIV
HIV, HCV, HSV, polio
TABLE 16-3 Mechanisms of Immune Evasion by Viruses
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

96. Mechanism of Immune Evasion Examples
Production of immunosuppressive
cytokine
Epstein-Barr (IL-10)
Infection and death or functional
impairment of immune cells
HIV
Inhibition of complement
activation
Recruitment of factor H
Incorporation of CD59 in viral envelope
HIV
HIV, vaccinia, human CMV
Inhibition of innate immunity
Inhibition of access to RIG-I
RNA sensor
Inhibition of PKR (signaling by
IFN receptor
Vaccinia, HIV
HIV, HCV, HSV, polio
TABLE 16-3 Mechanisms of Immune Evasion by Viruses
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

97. Mechanism of Immune Evasion Examples
Production of immunosuppressive
cytokine
Epstein-Barr (IL-10)
Infection and death or functional
impairment of immune cells
HIV
Inhibition of complement
activation
Recruitment of factor H
Incorporation of CD59 in viral envelope
HIV
HIV, vaccinia, human CMV
Inhibition of innate immunity
Inhibition of access to RIG-I
RNA sensor
Inhibition of PKR (signaling by
IFN receptor
Vaccinia, HIV
HIV, HCV, HSV, polio
TABLE 16-3 Mechanisms of Immune Evasion by Viruses
Abbas AK, Lichtman AH, Pillai S, editors. Cellular and molecular immunology. 8th ed. Philadelphia: Elsevier Saunders;2015.

98. Summary
• Innate immune mechanisms restrict the early stages
of infection and delay spread of virus.
: Interferon
: NK cells
: Macrophages

99. Summary
• As a viral infection proceeds, the adaptive (specific)
immune response unfolds.
: Ab & complement limit viral spread &
reinfection
: CD8+ CTLs destroy virus infected cells
: CD4+ T cells are a major effector cell
population

100. Summary
• Viruses have evolved strategies to evade the immune
response.
: Virus latency & antigenic variation are the
most effective mechanisms.
: Many DNA viruses have strategies to control
expression of MHC molecules.