CH 15

The _______ region at the end of each arm of the Y-shaped antibody molecule is responsible for antigen binding.

FAB

True or false: Macrophages cannot function to eliminate antigen without assistance from helper T cells.

False

______________ which include B cells and T cells, are the primary cell type involved in the adaptive immune responses.

Lymphocytes

A _______ cell provides the second signal confirming that an antigen-activated B cell needs to start proliferation and differentiation into a plasma cell.

T

Which type of antigen is most common?

T-dependent

What is it about the traits of a T-independent antigen that can activate a B cell without help from a T cell?

The high number of repeating identical epitopes can cross-link many BCRs at once, providing a strong activation signal without T cells.

An antigen is a molecule capable of interacting with ______.

an antibody molecule a B-cell receptor

Cell-mediated immunity defends against ______.

invaders residing within a cell

All of the following are true of antigen processing and presentation in B cells EXCEPT ______.

peptide fragments are loaded into B cell receptor molecules for presentation to helper T cells

Dendritic cells gather material by ______.

pinocytosis phagocytosis extending tentacle-like extensions between epithelial cells to mucosal surfaces

T cell

thymus

Cell-mediated immunity (CMI) deals with intracellular pathogens and antigens such as ______.

viruses replicating in a cell

B cell

Bone marrow

Cell-mediated immunity deals with microbial invaders residing within a host cell, such as a virus replicating inside a cell, whereas humoral immunity deals with invaders in the bloodstream and tissue fluids.

Cell-mediated immunity deals with microbial invaders residing within a host cell, such as a virus replicating inside a cell, whereas humoral immunity deals with invaders in the bloodstream and tissue fluids.

The two main categories of T lymphocytes necessary to mount a response against foreign pathogens are cytotoxic T cells and helper T cells.

The two main categories of T lymphocytes necessary to mount a response against foreign pathogens are cytotoxic T cells and helper T cells.

True or false: IgG accounts for approximately 80-85% of total antibody in the serum.

True

IgG ______.

accounts for 80-85% of circulating antibody levels easily leaves the bloodstream and enters tissues

Cytotoxic T cells (Tc cells) induce ______ in infected self cells and cancerous cells.

apoptosis

Two types of T cells are involved with eliminating antigen. What are they?

helper T cells cytotoxic T cells

Natural killer cells belong to the group of lymphocytes called ______.

innate lymphoid cells

The following steps occur during the B-cell response to T-dependent antigens. Place them in the correct sequence, starting with the earliest at the top.

1. B-cell receptor binds to antigen 2. B cell internalizes antigen 3. B cell degrades antigen into peptide fragments 4. peptide fragments are presented on MHC class II molecules 5. TH cells recognize antigen fragment and activates B call

A A T cell provides the second signal confirming that an antigen-activated B cell needs to start proliferation and differentiation into a plasma cell.

A T cell provides the second signal confirming that an antigen-activated B cell needs to start proliferation and differentiation into a plasma cell.

What are the basic functions of helper T cells?

Activation of macrophages Activation of B cells Coordination of activities of B cells, macrophages, and other T cells

Positive selection take place in T cells but not in B cells because ______.

B cells don't need to have peptides presented to them on an MHC molecule, so it doesn't matter if they can bind MHC or not

Humoral immunity is mediated by five classes of immunoglobulins: IgA__________

IgD IgE IgG IgM

The maternal immunoglobulin that protects the fetus and newborn is

IgG

______ is the only antibody class that can be transported across the placenta.

IgG

T cells

Interact with target cells and then cause changes in those cells

When a B cell receptor (BCR) binds antigen, and the naive B cell is activated by confirmation from a helper T cell, the B cell then begins to ______.

Multiply

Which of the following carries out cell-mediated immunity?

T cells

If an immune system lost the ability to make helper T cells, the B cells could still be activated by ______.

T-independent antigens polysaccharides

When a macrophage receives assistance from a helper T cell in the form of cytokines, it ______.

activates more potent destructive mechanisms for the cell, enhancing its antigen clearing capacity

Helper T cells orchestrate the immune response by ______.

activating B cells and macrophages directing the activities of B cells, macrophages, and T cells

Memory B cell production occurs ______.

after class switching has taken place

A plasma cell is ______.

an antibody-producing descendant of a B cell

Before a B cell undergoing antigen-induced activation can proliferate, it must usually get help from ______.

another type of lymphocyte--a helper T cell (TH).

The presence of ______ can initiate the classical pathway of complement activation.

antibodies bound to antigen

B cells

antibody response

The function of the two arms of the Y-shaped antibody molecule is to ______.

bind to epitopes, or antigenic determinants

The lymphatic system's primary role is to _______.

bring antigens into contact with lymphocytes, allowing activation, proliferation, and differentiation of specific B and T cells into effector cells

Antibody-antigen binding can activate the complement cascade via the ______

classical pathway

The portion of antibody molecules that has a consistent amino acid sequence regardless of the epitope recognized is referred to as the ______ region.

constant or Fc

Helper T cells secrete chemical signals known as ______ that stimulate the proliferation of B cells and macrophages.

cytokines

T lymphocytes exist in two major types. Those that are called _______ T cells are responsible for inducing apoptosis in self cells infected with viruses or are otherwise "corrupt".

cytotoxic

______ cells, a type of antigen-presenting cell, are responsible for initial activation of naive T lymphocytes in lymph nodes during a cell-mediated immune response.

dendritic

A particular type of cell from the innate immune responses is critical for initial T cell activation in lymph nodes. This cell is the ______.

dendritic cell

Most antigens are T-_________, meaning that T-helper cells are required for confirmation.

dependent

One of the traits of IgG molecules that gives them such a strong capacity for protective responses is their long ______-life of 21 days.

half

The type of T lymphocyte called ______ T cells play a major role in directing and assisting the various immune responses.

helper

A T-cell receptor (TCR) is ______.

is found on the surface of T cells only recognizes antigen that is presented by another cell is similar (but not identical) in function to a B cell receptor

IgM ______.

is the first class of antibody produced during a primary response to an antigen

The primary cellular participants in the adaptive immune responses are:

lymphocytes

The clonal selection theory states that there are ______.

many lymphocytes produced, but each has only one specific epitope it will react with

A B cell in a lymph node is a(n) ______ type of lymphocyte, while a plasma cell is a fully ______ lymphocyte.

mature but naive; differentiated

_______ B cells are long-lived and allow for a much faster response if the same antigen is encountered at a later date.

memory

An antigen interacting with a T-cell receptor ______.

must be broken down into peptide fragments and presented on an MHC molecule

Positive selection mechanisms in lymphocytes occurs ______.

only in T cells due to binding of a TCR to MHC molecules during development and screening in the thymus

When a helper T cell recognizes a peptide presented by a B cell or macrophage, it will ______.

secrete cytokines that will assist in the activation of the B cell or macrophage

The process that B cells use to generate diversity in the B-cell receptors is ______.

similar to the process that T cells use to generate diversity in T-cell receptors

Humoral immunity is generally used to eliminate extracellular antigens such as ______.

toxins viruses in tissue fluids bacteria

The main outcome of B cell activation is ______.

triggering the cell to multiply

When comparing two different antibody molecules that bind to different epitopes, the amino acid sequence in the _________region of each molecule will be different.

variable or Fab

The receptor on the surface of B cells is most similar to a(n) ______.

antibody molecule

The main function of the lymphatic system is to allow ________ to interact with and activate lymphocytes.

antigens

B cells with anti-self B-cell receptors (BCRs) undergoing negative selection in the bone marrow are induced to undergo______

apoptosis

The variable region on an antibody molecule is found ______.

at the end of the Fab regions

The basic functions of effector cytotoxic cells (TC cells) include ______.

destruction of cancerous self cells induction of apoptosis in infected self cells

If a developing T cell in the thymus recognizes a self antigen bound to an MHC molecule with its T-cell receptor (TCR), that T cell is ______.

eliminated through induction of apoptosis

Humoral immunity is best at eliminating ______ antigens such as viruses in the bloodstream or tissue fluid, whereas cell-mediated immunity removes ______ antigens such as viruses within host cells.

extracellular; intracellular

The major classes of immunoglobulin molecules correspond to the _______.

five general types of constant regions.

Unlike B and T cells, NK cells ______.

do not have antigen specific receptors

The human genome ______.

does not have the coding capacity to have one gene per specific antibody molecule

Clonal selection is a critical theme in the adaptive immune response. The two main features are that ______.

each lymphocyte recognizes and responds to only a single epitope a population of lymphocytes able to recognize a functionally limitless variety of antigens is generated

The cells that have the general role of interacting with target cells and then inducing changes in them are ______.

helper T cells cytotoxic T cells

Maternal IgG can protect a newborn after birth by ______.

virtue of its long half life--it is present in the newborn's blood for nearly 6 months after birth being present in colostrum, the first breast milk produced after birth, supplementing the IgG carried in the newborn's blood after it is born