Exam 4: Ch 20

Question 1

primary lymphoid organs
and
secondary lymphoid organs

Answer 1

primary: thalamus and bone marrow

secondary: (the rest) tonsil, lymph nodes, spleen, appendix, lymph vessels, and Peyer’s patches of intestine

Question 2

B cells and T cells are lymphocytes produced where?

Answer 2

bone marrow

Question 3

lymphocyte

Answer 3

Type of leukocyte possessing specific receptors for recognizing antigen or MHC I molecules presented on other cells; includes NK cells, B cells, and T cells

Question 4

antigen

Answer 4

Any component that can be specifically bound by an immune receptor, namely a T-cell receptor (TCR) or an immunoglobulin (Ig)

Question 5

B cell

Answer 5

Lymphocyte of the adaptive immune system expressing immunoglobulin B-cell receptors (BCRs) on their surface; give rise to antibody-secreting plasma cells; also called B lymphocyte

Question 6

T cell

Answer 6

Lymphocyte of the adaptive immune system that matures in the thymus and expresses surface T-cell receptors (TCRs); also called T lymphocyte

Question 7

epitope

Answer 7

Single antigenic site on a molecule that is recognized and bound by an immune receptor, such as an immunoglobulin (BCR or antibody) or TCR. the smallest part of an antigen

Question 8

primary immune response

Answer 8

Response of the adaptive system that occurs with first exposure to an antigen, involving activation of naïve T cells and B cells, in the absence of immunological memory

Question 9

anamnestic (secondary) response

Answer 9

Immune response that originates from the stimulation of memory cells and is characterized by a faster and more vigorous adaptive immune response upon repeated exposure to antigen; see also memory response

Question 10

antigen-presenting cell (APC)

Answer 10

The only cells capable of activating T cells.

Cell capable of processing and presenting antigen in association with MHC molecules; includes dendritic cells, macrophages, and B cells.

Question 11

dendritic cell

Answer 11

Migrating antigen-presenting cell found in most tissues of the body, characterized by extensive cytoplasmic projections

Question 12

MHC I binds with

Answer 12

CD8

Question 13

MHC II binds with

Answer 13

CD4

Question 14

CD4+ T cell

Answer 14

T lymphocyte expressing the surface molecule CD4

Question 15

CD8+ T cell

Answer 15

T lymphocyte expressing the surface molecule CD8

Question 16

Activation of a T cell results in?

Answer 16

production of interleukin-2 (IL-2), which induces clonal expansion to produce a population of genetically identical memory T cells and effector cells, all possessing the same antigen-specific TCR.

Question 17

T helper Cell (TH cell)

Answer 17

Effector CD4+ T cell that secretes cytokines involved in directing immune responses

Question 18

Cytotoxic T Cell (TC Cell)

Answer 18

Effector CD8+ T cell that induces apoptosis in target cells through MHC I:antigen binding followed by the release of perforin and granzyme

Question 19

exogenous antigen

Answer 19

Peptide antigen that enters the endocytic pathway from outside the cell and is presented on MHC II molecules

Question 20

endogenous antigen

Answer 20

Peptide antigen that originates from the cytoplasm of a cell and is presented on MHC I molecules

Question 21

cross-presentation

Answer 21

Pathway in antigen-presenting cells that shuttles proteins from the endocytic pathway into the endogenous pathway to allow for both CD4+ and CD8+ T-cell activation

Question 22

humoral immune response

Answer 22

Adaptive immune response dominated by TH2 cells and characterized by production of large amounts of antibody in response to extracellular pathogens or toxins

Question 23

TH1 Cell

Answer 23

Cell belonging to a subset of T helper (TH) cells that secretes cytokines, such as IL-2, IFN-γ, and TNF-β, to produce a cell-mediated immune response

Question 24

cell-mediated immune response

Answer 24

Immune response dominated by TH1 cells, TC cells, increased activation of macrophages, and inflammation in response to the presence of intracellular pathogens

Question 25

class-switching

Answer 25

Genetic process in activated B cells that results in production of one of the classes of IgA, IgG, or IgE immunoglobulin from the initial production of class IgM

Question 26

T-independent antigen

Answer 26

Antigen that can stimulate B cells to proliferate into antibody-secreting plasma cells without requiring B-cell interaction with T cells; possesses highly repetitive structures with the ability to crosslink several BCRs on a B cell

Question 27

What is the effector function of B-cells versus that of T-cells?

Answer 27

B-cells produce antibodies and T cells target and destroy cells

Question 28

MHC I molecules versus MHC II molecules: endogenous versus exogenous antigen presentation

Answer 28

exogenous antigens are peptide antigens that enter the endocytic pathway from outside the cell and are presented on MHC II molecules that bind to CD4.
endogenous antigens are peptide antigens that originate from the cytoplasm of a cell and are presented on MHC I molecules and bind to CD8.

Question 29

The functions of the different antibody classes: Which is primarily found in secretions, which is
involved in allergies and parasitic infections, which is the major class found in serum and
capable of crossing the placenta, which is the first class made during the primary immune
response?

Answer 29

IgA is primarily found in secretions. Functions to the agglutination of antigen; binding to phagocyte FC receptors for Phagocytosis

IgE is involved in allergies and parasitic infections. Functions to the Crosslinking with antigen induces degranulation in mast cells, eosinophils, basophils

IgG is the major class found in serum and
capable of crossing the placenta. Functions in Complement activation; opsonization for
phagocytosis; toxin neutralization; ADCC
killing by NK cells

IgM is the first class made during the primary immune response. Functions in Complement activation; agglutination of
antigen for phagocytosis

Question 30

Know the difference between an antigen and its epitopes

Answer 30

epitopes are the actual fragments or extensions of an antigen that can interact with immune receptors.

Question 31

What are the differences between CD4 versus CD8 T-cells?

Answer 31

CD4 cells are helper T cells and CD8 are cytotoxic cells that directly attack foreign microbes.

Question 32

Which immune cells are antigen presenting cells?

Answer 32

macrophages, dendritic cells, and B cells.