Lecture 6: Intro To Immunology

Question 1

What is the most important cytokine that caues the multipotent hematopoietic stem cell to differentiate into the common lymphoid progenitor?

Answer 1

IL-7

[the common lymphoid progenitor cell line then branches to NK cells, T cells, and B cells]

Question 2

In the initial generation of lymphocytes, what 2 cell types are generated in the bone marrow?

Answer 2

B cells and Pro-T cells

Question 3

DiGeorge syndrome results from a contiguous deletion of _________ through _________.

Symptoms inclue thymic _________ or ________, hyperparathyroidism, congenital heart malformation, and/or characteristic _________.

Patients experience recurrent infections soon after birth.

Answer 3

22q11.21 through 22q11.23

Hypoplasia; aplasia; facies

Question 4

True or false: complete DiGeorge syndrome is fatal without treatment

Answer 4

True

Absence of the thymus would result in no T cell maturation. Mature T cells are also used in the complete differentiation of B cells, so you are essentially losing the adaptive branch of your immune system.

Question 5

How would you classify the lymphocytes constantly recirculating between the blood and peripheral lymphoid organs?

Answer 5

Mature naive (because they are developmentally mature, but have not yet encountered an antigen)

Question 6

What happens to migrating T cells and B cells if they become activated by APCs?

Answer 6

They stop migration in order to become fully activated to perform their effector function

Question 7

Of all the secondary lymphoid organs, rank the spleen, LNs, intestines (GALT), and lungs (BALT) in order of most lymphocytes to least lymphocytes

Answer 7

Lymph nodes
Spleen
Intestines
Lungs

Question 8

What is the primary APC responsible for travelling to secondary lymphoid tissues and presenting Ag to mature naive T cells?

Answer 8

Dendritic cells

[the antigen is presented within MHC class I or II]

Question 9

Humoral immunity is the branch of adaptive immunity mediated by antibodies produced by _____ cells and ______ cells.

Humoral immunity is the principle adaptive defense against ____________ pathogens

Answer 9

B; plasma

Extracellular

Question 10

Antibodies complexed with phagocytes participate in what 2 effector functions?

Answer 10

Neutralization of microbes and toxins

Opsonization and phagocytosis of microbes

Question 11

What is the effector function of antibodies complexed with NK cells?

Answer 11

Antibody-dependent cellular cytotoxicity (ADCC)

Question 12

What is the effector function of antibody-mediated complement activation (classical pathway)

Answer 12

Phagocytosis of microbes opsonized with complement fragments (C3b)

Inflammation

Lysis of microbes

Question 13

During pregnancy, the mother provides a physical barrier for the fetus against microorganisms.

The fetus receives ____ from the maternal circulation.

Additional protection will be gained through ____ secreted in breast milk.

Answer 13

IgG

IgA

Question 14

Cell-mediated immunity is a branch of adaptive immunity mediated by _____________ and ___________. Cell mediated immunity is the principle adaptive defense against ____________ pathogens.

Answer 14

T lymphocytes; macrophages

Intracellular

Question 15

What are the “two paths” of cell-mediated immunity?

Answer 15

CD4+ effector T cells interact with phagocytes that have ingested microbes in vesicles –> cytokine secretion –> macrophage activation and killing of ingested microbes

CD8+ CTL interacts with infected cell with microbes or antigens in the cytoplasm –> direct killing of infected cell

Question 16

What are the 3 sub-types of CD4+ T helper cells?

Answer 16

Th1
Th2
Th17

Question 17

What is the signature cytokine of Th1 cells and what is the immune reaction?

Answer 17

IFN-y

Leads to macrophage activation and IgG production

Question 18

What are the signature cytokines of Th2 cells and what are the immune reactions?

Answer 18

IL-4
IL-5
IL-13

Lead to mast cell and eosinophil activation, IgE production, and M2 macrophage activation (alternative)

Question 19

What are the signature cytokines of Th17 cells and what is the immune reaction?

Answer 19

IL-17A
IL-17F
IL-22

Leads to neutrophilic and monocytic inflammation

Question 20

Th1 cells defend the host against what type of pathogen?

Answer 20

Intracellular microbes

[role in autoimmune disease; tissue damage associated with chronic infections]

Question 21

Th2 cells protect the host against what type of microbes?

Answer 21

Helminthic parasites

[also role in allergic diseases]

Question 22

Th17 cells provide protection against what types of pathogens?

Answer 22

Extracellular bacteria
Fungi

[also play a role in autoimmune inflammatory diseases]

Question 23

APCs (like dendritic cells or macrophages) with ingested microbes utilize ______ to activate naive CD4+ T cells to differentiate them into Th1 effector T cells.

The Th1 effector cell can then activate macrophages to kill the microbes via _______ (cytokine)

Answer 23

IL-12

IFN-y

Question 24

CD8+ cytotoxic T lymphocytes are antigen-specific and have MHC restricted cytotoxicity.

They are involved in the killing of ___________ pathogens using stored lytic _______ that contain cytotoxins.

Cytotoxins are delivered directly onto the surfaces of infected target cells.

Answer 24

Intracellular

Granules

Question 25

What does it mean to say that cooperation exists between CD4 and CD8 T cell subsets?

Answer 25

A macrophage that has phagocytosed microbes in vesicles and cytosol can be activated by IFN-y secreted by CD4+ T cells. The microbes will then be killed in the phagolysosome, and the infected cell can then be killed by CD8+ CTLs

Question 26

Adaptive immune responses provide ongoing protection by production of memory lymphocytes. During the primary immune response, when the Ag is first encountered, activation of naive cells takes place to form effector functions, and there is generation of ___________ cells. The secondary immune response, when the Ag is encountered again, the memory cells are activated and there is a stronger, ________ immune response

Answer 26

Memory | Faster

Question 27

____________ = antigenic stimulus that elicits specific adaptive immune responses that can be recalled during subsequent infections

Answer 27

Immunization

Question 28

__________ immunization is the introduction of antibody or antiserum into a naive recipient

Answer 28

Passive

Question 29

________ immunization is the introduction of an antigen that provokes an adaptive immune response

Answer 29

Active

Question 30

___________ is the intentional delivery of an antigenic stimulus

Answer 30

Vaccination

Question 31

What are the 2 identifiers on B cells?

Answer 31

CD19 | CD21

Question 32

What is the identifier present on all T cells?

Answer 32

CD3

Question 33

What are the identifiers on helper T cells?

Answer 33

CD3 | CD4

Question 34

CD3+ CD4+ helper T cells can be further identified based on their cytokine secretion profile. What cytokines does Th1 produce?

Answer 34

IL-2 IL-12 IFN-y

Question 35

CD3+ CD4+ helper T cells can be further identified based on their cytokine secretion profile. What cytokines does Th2 produce?

Answer 35

IL-4 IL-5 IL-13

Question 36

CD3+ CD4+ helper T cells can be further identified based on their cytokine secretion profile. What cytokines does Th17 produce?

Answer 36

IL-17 | IL-22

Question 37

What are the identifiers present on Treg cells?

Answer 37

CD3 CD4 CD25

Question 38

What cytokines are secreted by Treg cells?

Answer 38

IL-10 | TGF-beta

Question 39

What are the identifiers on CTLs?

Answer 39

CD3 | CD8