Exam 9: Chapter 11

Question 1

What role do effector memory T cells hold?

Answer 1

They specialize in homing to inflamed tissues and functioning within them

Question 2

Why are memory T cells harder to trace than memory B cells?

Answer 2

The TCR does not undergo somatic hypermutation or class switch recombination

Question 3

When can the prevention of naïve B cell response be problematic?

Answer 3

When dealing with a pathogen that can mutate frequently

Question 4

Why can the prevention of naïve B cell response be problematic?

Answer 4

It leads to the gradual weakening of the response to a pathogen and an increase in the severity of disease (original antigenic sin)

Question 5

What are advantages of memory T cells?

Answer 5

Activated faster than naïve T cells, co-stimulation not required for memory T cell activation

Question 6

What happens to the antibodies that are produces by plasma cells after infection?

Answer 6

They eventually degrade and disappear from the serum

Question 7

How long do plasma cells make antibodies after infection?

Answer 7

A few months

Question 8

What role do central memory T cells hold?

Answer 8

They make CD40L, and home to T cell areas of secondary lymphoid organs to interact with B cells

Question 9

What do conjugate vaccines take advantage of?

Answer 9

The need for conjugate pairs between B and T cells

Question 10

What allows memory T cells to survive for long periods of time?

Answer 10

IL-7 and IL-15 produced by activated naïve T cells make enough extra cytokine to maintain memory T cells

Question 11

Why does the prevention of a naïve B cell response by circulating antibody make sense?

Answer 11

It allows for immune response resources to be conserved when responding to an invariant pathogen

Question 12

What are vaccines designed to do?

Answer 12

Stimulate the production of memory cells

Question 13

What cells do effector memory T cells differentiate into?

Answer 13

CD8+, TH1, TH17, or TH2 cells

Question 14

How does a virus become attenuated?

Answer 14

A virus present in humans is grown in cells of other organisms and allowed to mutate; when transferred back to humans, the virus can no longer grow well in human cells and cause disease

Question 15

What are the three purposes of a successful primary immune response?

Answer 15

Clear the infection, provide protection against immediate reinfection, provide long term immunological memory

Question 16

What happens when a naïve B cell binds pathogen coated with specific antibody?

Answer 16

A negative signal is given to the naïve B cell to prevent its activation

Question 17

Why are memory cells more effective in fighting infections?

Answer 17

1. Memory cells are more sensitive and more easily activated
2. Memory cells that recognize a particular antigen are more abundant than naïve cells that recognize the same antigen
3. Memory B cells have undergone class switch, somatic hypermutation, and affinity maturation
4. Activated memory B cells continue to undergo somatic hypermutation and affinity maturation

Question 18

What happens when a memory B cell binds pathogen coated with specific antibody?

Answer 18

Memory B cell is activated and becomes an antibody-producing plasma cell

Question 19

What would happen if an Rh- mother were not treated with anti-Rh IgG while carrying her first Rh+ fetus?

Answer 19

The secondary immune response would lead to massive destruction of fetal erythrocytes, causing life-threatening anemia in the second (and all subsequent) baby

Question 20

What are the advantages that memory B cells have over naïve B cells?

Answer 20

High affinity BCR, lower activation threshold, quicker response, more efficient antigen processing, higher levels of MHC class II, differentiate faster

Question 21

What consequence stems from the property that numbers of memory T cells are held constant?

Answer 21

When new memory T cells develop during the response to infection, older memory CD8+ cells must be lost to keep the population constant

Question 22

What prevent s re-infection immediately after an infection is cleared?

Answer 22

Combined action of post-infection antibodies and the innate immune response

Question 23

What are the two kinds of memory T cells?

Answer 23

Effector memory T cells and central memory T cells