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Immunology > Cells and Tissues of the Adaptive Immune System (Lec 2) > Flashcards

Cells and Tissues of the Adaptive Immune System (Lec 2) Flashcards

1
Q

Naive lymphocytes typically die if they do not recognize an antigen after how long?

A

1 to 3 months

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2
Q

Why are naive and memory lymphocytes both called resting lymphocytes?

A

they are not actively dividing, nor are they performing effector functions

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3
Q

Naive lymphocytes are in a state of rest. Which phase of the cell cycle is this?

A

G0

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4
Q

What does the survival of naive lymphocytes depend on?

A

Antigen receptors and cytokines

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5
Q

True or False?
Naive T lymphocytes (TCR) recognize various self antigens weakly, enough to generate survival signals but without triggering clonal expansion and differentiation into effector cells.

A

True

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6
Q

What is the most important cytokine for survival of naive T cells?

A

IL-7, promotes low-level cycling of naive T cells

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7
Q

True or False?

BAFF is not required for naive B cell survival.

A

False. It is required

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8
Q

True or False?

Cytokines serve as soluble regulatory factors or “messengers” for the immune system

A

ture

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9
Q

Which cytokines play an important role in T cell development?

A

IL-1,2,6,&7

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10
Q

True or False?

Following migration from the thymus, most mature naive T cells are maintained in the periphery without proliferating

A

True

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11
Q

In T cell selection process, highly self-reactive T cells are removed and two different kinds of T cells develop. What are the two kinds of T cells?

A

T helper cells - express CD4 and provide help for B cell growth and differentiation

Cytotoxic T lymphocytes - express CD8 and recognize and kill virus-infected cells

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12
Q

When do B cells start to develop from stem cells?

A

around the 14th week of gestation

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13
Q

Where does differentiation into B cells occur before and after birth?

A

before birth - fetal liver

after birth - bone marrow

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14
Q

Which cytokines play an important role in B cell development?

A

IL-1,6,&7

note: IL-2 is found in T cell development but not B cell development

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15
Q

B cells, when activated by an antigen and with T cell help, proliferate in germinal centers and mature into two types of cells called?

A

memory cells or plasma cells

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16
Q

What do plasma cells do?

A

produce and secrete large amounts of antibodies

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17
Q

True or False?

B cells present antigens to helper T cells

A

true

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18
Q

Where are the only 3 places lymphocytes do not reach?

A

eye, brain, testicles

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19
Q

Lymphocytes reach the intestine via a specialized endothelium of post capillary venues called?

A

High endothelium venules (HEV)

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20
Q

Cells of HEV express high levels of adhesion molecules that serve as _____ for lymphocytes?

A

homing receptors

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21
Q

In response to chemokines, how do lymphocytes migrate into tissue?

A

by diapedesis

22
Q

How do lymphocytes reenter the circulation?

A

via efferent lymph vessels that merge into the thoracic duct

23
Q

Where are antigens captured?

A

from a site of infection and the draining lymph node to which those antigens are transported and where the immune response is initiated

24
Q

What are the steps in lymphocyte activation?

A

1) naive T cells and immature B cells migrate into secondary lymphoid organs such as lymph nodes and spleen.
2) B cells complete their maturation in LNs and spleen
3) naive B and T cells activated by antigens differentiate into effector or memory lymphocytes
4) some effector and memory lymphocytes migrate into peripheral tissue sites of infection
5) antibodies secreted by effector B cells in LNs, spleen, and bone marrow enter the blood and are delivered to sites of infection

25
Q

What signal do Antigen-presenting cells give?

A

stimulate the proliferation and differentiation of the lymphocytes

26
Q

True or False?
Antigen-presenting cell usually refers to a cell that displays antigen to T lymphocyte because B lymphocytes do not need antigen-presenting cells for their activation.

A

true

27
Q

What is the major type of APC that is involved in initiating T cell responses?

A

dendritic cell (DC)

28
Q

True or False?

Macrophages and B cells are not APCs

A

false. they are both APCs

29
Q

What is the function of the specialized cell type called the follicular DC?

A

displays antigens to B lymphocytes during particular phases of the humoral immune response

30
Q

DCs and macrophages provide a link between?

A

innate and adaptive immunity

31
Q

True or False?

DCs have short membranous projections and do not have phagocytic capabilities.

A

False. DCs have long membranous projections and have phagocytic capabilities

32
Q

Maturation of DCs is dependent on what?

A

cytokine called Flt3 Ligand

note: it binds to the tyrosine kinase receptor on precursor cells

33
Q

True or False?

Macrophages and DCs express receptors that recognize antigens made by mammalian cells, not microbes.

A

False. Macrophages and DCs express receptors that recognize antigens made by microbes, not by mammalian cells

34
Q

True or False?

Activated DCs also secrete cytokines

A

true

35
Q

Where are classical DCs found?

A

skin, mucosa, and organ parenchyma

36
Q

Upon activation by microbes, classical DCs migrate to lymph nodes where they…?

A

display microbial protein antigens to T lymphocytes

37
Q

True or False

Plasmacytoid DCs are late cellular responders to viral infection.

A

False. early cellular responders

38
Q

What do plasmacytoid DCs recognize?

A

nucleic acids of intracellular viruses

39
Q

True or False?

IFN-alpha/beta have potent antiviral activities.

A

true

40
Q

True or False?

During the inflammatory response in the tissue, DCs may also be derived from circulating monocytes?

A

true

41
Q

Where do Follicular Dendritic Cells (FDCs) reside?

A

LNs, spleen, and mucosal lymphoid tissue

42
Q

True or False?

FDCs are unrelated to the DCs that present antigens to T lymphocytes.

A

true

43
Q

What is the function of FDCs?

A

bind and display protein antigens on their surfaces for recognition by B lymphocytes

44
Q

FDCs have remarkable ability to…?

A

retain complement-fixed antigens on their cell surface for extended periods of time

45
Q

Retained immune complexes have long been known to provide…?

A

antigen stimulus that drives antibody affinity maturation

46
Q

True or False?
The effector functions of Innate Lymphoid Cells (ILCs) are similar to those of T cells, but they lack T cell antigen receptors

A

true

47
Q

What are the major functions of ILCs?

A

to provide early defense against infectious pathogens

to recognize stressed and damaged host cells and help to eliminate these cells

to influence the nature of the subsequent adaptive immune response

48
Q

What are the first and best characterized innate lymphoid cells?

A

natural killer cells

49
Q

What cytokine do NK cells secrete?

A

IFN-gamma

50
Q

True or False?

Naive T and B lymphocytes migrate to the same areas of a LN

A

False, they have their own zones and are drawn by chemokines that are produced in these areas

51
Q

True or False?
After picking up antigens and entering LN through afferent lymphatic vessels, DCs migrate to the B cell-rich area of the LN.

A

False, migrate to the T cell-rich area of the LN

Immunology (12 decks)

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