Immunity to Infections

Question 1

what are the three mechanisms of innate immunity to extracellular bacteria

Answer 1

1. complement activation
2. opsonization and phagocytosis
3. stimulation of inflammatory reactions via anaphylatoxin

Question 2

how does humoral immunity deal with extracellular bacteria

Answer 2

eliminate microbes and neutralize their toxins via antibodies that recognize:
- cell wall antigens
- secreted and cell-associated toxins

Question 3

in general, humoral immunity uses which cells and in turn what else

Answer 3

B cells, antibody and Igs

Question 4

what happens with cell-mediated immunity to extracellular bacteria (3)

Answer 4

bacterial protein antigens are processed by DC, and activate CD4 helper T cells for:
- production of IL-17 and neutrophil recruitment
- production of IFNy and activation of macrophages
- B cell help

Question 5

in general, what type of immune response is elicited by extracellular bacteria

Answer 5

complement, phagocytes, and Ig

Question 6

in general, what type of immune response is elicited by intracellular bacteria

Answer 6

phagocytes, NK cells, cell mediated

Question 7

intracellular bacteria elimination requires which immunity

Answer 7

cell-mediated

Question 8

how does the innate immunity help with intracellular bacteria

Answer 8

1. phagocytes and complement before cells become infected
2. NK cells are activated directly or via IL-12 produced by macrophages
   - (NK cells produce IFNy which activated macrophages)

Question 9

how does adaptive immunity help with intracellular bacteria

Answer 9

1. CD4 T cells differentiate into Th1 effectors via IL-12
2. macrophage activation by T cell-derived signals (IFNy and CD40-CD40L)
3. Antibodies (against TB for ex.)

Question 10

cells infected by intracellular bacteria can also be lysed by which cell

Answer 10

CD8 cytotoxic cells (CTL)

Question 11

how does the innate immunity respond to fungi

Answer 11

1. neutrophils and macrophages phagocytose fungi
2. ILC1 and ILC3 are protective
3. Th1 and Th17 responses are protective

Question 12

what increases risk of oral candidiasis or thrush

Answer 12

wearing upper dentures or dry mouth

Question 13

in immune response to viruses, what does type I IFN lead to

Answer 13

antiviral state and activated NK cells

Question 14

T/F for virus infection, innate and adaptive immune responses block infection and lead to elimination of infected cells

Answer 14

True

Question 15

what is involved with the innate immune response to viruses

Answer 15

IFNa and NK cell killing

Question 16

what do antibodies do in immune response to viruses

Answer 16

1. neutralize virus
2. activate complement
3. lead to opsonization of viral particles

Question 17

what kills viro-infected cells

Answer 17

CD8 T cells

Question 18

what is involved in the adaptive immunity to protozoa

Answer 18

1. macrophage activation by Th1 cell-derived cytokines
   - activation of Th2 cells results in increased protozoa survival and exacerbation of lesions (because stops macrophage activation)
2. cytotoxic T cell responses against lytic protozoa

Question 19

what is involved in the adaptive immunity to helminths

Answer 19

• activation of Th2 cells results in killing of helminth not infected cells

Question 20

in adaptive immunity to helminths, production of IL-4 induces what

Answer 20

IgE

Question 21

in adaptive immunity to helminths, production of IL-5 stimulates what

Answer 21

eosinophil development and activation

Question 22

in adaptive immunity to helminths, how are they killed

Answer 22

degranulation of eosinophils

Question 23

what are the consequence of micro-induced immune response

Answer 23

1. granuloma and immune complex deposit
2. inflammation

Question 24

what are the three ways microbes evade the immune system

Answer 24

1. antigenic variation
2. inhibition of complement activation
3. resistance to phagocytosis

Question 25

how are viruses able to have antigenic variation

Answer 25

1. point mutations (antigenic drift)
2. reassortment of virus RNA genomes (antigenic shift) responsible for influenza pandemics

Question 26

what is the most effective vaccine

Answer 26

production of high-affinity neutralizing antibodies and memory cells

Question 27

what does caries vaccine do

Answer 27

1. enhanced levels of antigen specific secretory IgA
2. reduction of strep. mutans in plaque