immune_memory_flashcards

Question 1

Front

Answer 1

Back

Question 2

What is immune memory?

Answer 2

Feature of adaptive immune system - pool of antigen specific cells following infection with enhanced ability to respond to a second infection.

Question 3

What cells are involved in presenting peptides to T lymphocytes to initiate an acquired immune response?

Answer 3

Antigen presenting cells (APCs - macrophages, B lymphocytes, Langerhans cells, dendritic cells).

Question 4

What are the markers for memory T cells and naïve T cells?

Answer 4

CD45 RO = memory T cells, CD45 RA = naïve T cells.

Question 5

How long do memory cells remain following an infection?

Answer 5

Memory cells remain for a long time following infection.

Question 6

Do memory cells continue to proliferate after infection?

Answer 6

Yes, they continue to proliferate at a low rate.

Question 7

What is the response of memory cells to subsequent exposure to an antigen?

Answer 7

Rapid and robust response, easier to activate than naïve cells.

Question 8

What influences the migration and adhesion of memory T cells?

Answer 8

Different cell surface markers.

Question 9

Can memory T cells access non-lymphoid tissue?

Answer 9

Yes, they can access non-lymphoid tissue (the sites of microbe entry).

Question 10

Where are central memory cells found?

Answer 10

In lymph nodes & tonsils - roll along and extravasate in High Endothelial Venules (HEVs).

Question 11

Where are effector memory cells found?

Answer 11

In liver, lungs, and gut.

Question 12

What markers do central memory cells express?

Answer 12

CCR7+ and CD62L high (allow entry/migrate via HEVs to peripheral lymph nodes).

Question 13

What markers do effector memory cells express?

Answer 13

CCR7-ve and CD62L low (therefore not found in lymph nodes).

Question 14

What do central memory cells produce?

Answer 14

IL-2 (to support other cells).

Question 15

What do effector memory cells produce?

Answer 15

Perforin and IFN-γ.

Question 16

Which population has more central memory cells, CD4 or CD8?

Answer 16

More central memory in CD4 population.

Question 17

Which population has more effector memory cells, CD4 or CD8?

Answer 17

More effector memory in CD8 population.

Question 18

Describe the process of immune memory development after exposure to a pathogen.

Answer 18

Exposure to pathogen → Antigen(s) stimulation of specific T and B lymphocytes → Expansion → Some lymphocytes become effector cells and some become memory cells → Immunologic memory develops (long lived, up to 65 years).

Question 19

What are the steps involved in the expansion of specific T and B lymphocytes?

Answer 19

Antigen stimulation of specific T and B lymphocytes leads to their expansion.

Question 20

What do some lymphocytes become after the expansion?

Answer 20

Effector cells and memory cells.

Question 21

What type of immunoglobulins do B cells produce in the memory response?

Answer 21

IgG and some IgM.

Question 22

What happens to B cells stimulated by an antigen?

Answer 22

Expansion/isotype switching (due to cytokines provided by T helper cells) → Plasma cells producing antibody/memory cells.

Question 23

What type of cells can memory B cells differentiate into?

Answer 23

Memory cells that can differentiate into plasma cells (long lived).

Question 24

What is the response of memory B cells compared to the first exposure?

Answer 24

Quicker response, more antibodies, higher affinity antibodies, more IgG, and generally better antibodies.

Question 25

Describe the Mantoux Test procedure.

Answer 25

Inject 0.1 ml of 5 tuberculin (purified protein derivative) units intradermally, examine arm 48-72 hrs after.

Question 26

What indicates a positive Mantoux Test result?

Answer 26

Induration (swelling that can be felt) of at least 10 mm in diameter (erythema around not measured).

Question 27

What does a positive Mantoux Test imply?

Answer 27

Previous exposure to tuberculin protein, which could represent previous BCG exposure.