BHS 316 Quiz 3

The primary way in the which an antibody differs from a BCR is:

A BCR contains anchored into the plasma membrane of a B cell

Put the following events in the activation of a B cell in order, from beginning to end:

A co-stimulatory signal is received by the B cell Third step BCRs bind to their cognate antigen First step BCRs become crosslinked Second step The B cell is activated Fourth step

The BCR is made up of what 2 separate proteins:

A heavy chain and a light chain

Any molecule that can cause an allergic reaction is called:

An allergen

The antibody that fixes complement most efficiently in the classical activation pathway is [ Select ] and other antibody that can fix complement, although less efficiently, is [ Select ].

Answer 1: IgM Answer 2: IgG

Activation of [ Select ] by the [ Select ] occurs when [ Select ] causes C1 complexes to lose their inhibitors, resulting the ability of the C1 complexes to form [ Select ]. This process is called [ Select ].

Answer 1: The complement cascade Answer 2: Classical pathway Answer 3: IgM or IgG Answer 4: C3 convertase Answer 5: Complement fixation

When the B cell's [select] binds to a complement fragment on an opsonized antigen, it makes the B cell [select]:

Answer 1: complement receptor Answer 2: more sensitive to the invader

T cell-independent activation of a B cell depends on two signals. The primary signal is the [ Select ] and an example of the co-stimulatory signal is [ Select ].

Answer 1: Crosslinking of BCRs Answer 2: A Toll-like receptor on the surface of a B cell binding to a molecule characteristic of a pathogen

T cell-dependent activation of a B cell depends on two signals. The primary signal is the [ Select ] and the co-stimulatory signal is the [ Select ].

Answer 1: Crosslinking of BCRs Answer 2: Binding of CD40L on a helper T cell to the CD40 receptor on a B cell

The portion of the antibody that changes during somatic hypermutation is the [ Select ], and the portion of the antibody that changes during class switching is the [ Select ].

Answer 1: Fab region Answer 2: Fc region

On a B cell, the clustering of BCRs causes crosslinking. On a mast cell, the clustering of [ Select ] causes a similar crosslinking, which results in a signal to [ Select ].

Answer 1: Fc receptors Answer 2: Degranulation

The Fab region of an IgM molecule binds [ Select ] and the Fc region of an IgM molecule binds [ Select ].

Answer 1: Its cognate antigen Answer 2: C1 complexes

Every mature B cell can produce [ Select ] copy(ies) of [ Select ] kind(s) of BCRs. Each BCR is made up of [ Select ] kind(s) of heavy chains and [ Select ] kind(s) of light chains. A single B cell displays [ Select ] kind(s) of individual BCRs on its plasma membrane, and the population of B cells in your body collectively display [ Select ] kind(s) of BCRs in total.

Answer 1: Many Answer 2: Exactly one Answer 3: Exactly one Answer 4: Exactly one Answer 5: Exactly one Answer 6: Many

A [ Select ] is a B cell that defends you against future infections from a pathogen to which you have been exposed before, and a [ Select ] is a B cell that produces massive quantities of antibodies. A [ Select ] lives only a few days, but a [ Select ] lives for years. The generation of [ Select ] is one of the reasons that vaccines are effective.

Answer 1: Memory B cell Answer 2: Plasma B cell Answer 3: Plasma B cell Answer 4: Memory B cell Answer 5: Memory B cells

Substances that are not BCRs but causes BCRs to crosslink when they bind to the surface of a B cell are called [ Select ], and the type of B cell activation that results is called [ Select ].

Answer 1: Mitogens Answer 2: Polyclonal Activation

BCRs recognize antigens composed of [ Select ], and helper T cells recognize antigens composed of [ Select ].

Answer 1: Proteins, fats, and sugars Answer 2: Proteins only

In the classical pathway, IgM initially binds to [ Select ]. Next, several [ Select ] bind to [ Select ]. This causes the release of [ Select ], resulting the in activation of the [ Select ].

Answer 1: The pathogen Answer 2: C1 complexes Answer 3: The FC region of IgM Answer 4: The C1 inhibitors Answer 5: Complement cascade

The process by which IgG forms a bridge between a natural killer cell and one of our own cells that is infected with a virus, making the NK cell a more effective killer is called:

Antibody-dependent cellular cytotoxicity

The kinds of B cells that typically undergo somatic hypermutation and/or class switching are:

B cells that have been activated through T cell-dependent activation

Which of the following statements about T-cell independent-activation of B cells is correct (check all that apply):

BCRs must bind their cognate antigen for activation to occur BCRs must be crosslinked for activation to occur The BCRs on the surface of any one B cell all recognize the same antigen

Which of the following statements about both T cell-dependent and T-cell independent B cell activation is correct (check all that apply):

BCRs must bind their cognate antigen for activation to occur BCRs must be crosslinked for activation to occur The BCRs on the surface of any one B cell all recognize the same antigen

Which of the following statements about T-cell independent activation of B cells is correct (check all that apply):

BCRs must bind their cognate antigen for activation to occur The BCRs on the surface of any one B cell all recognize the same antigen BCRs must be crosslinked for activation to occur

Which of the following statements about T cell-dependent B cell activation is correct (check all that apply):

BCRs must bind their cognate antigen for activation to occur The binding of CD40L on helper T cells to the CD40 receptor on the surface of a B cell is required for activation The BCRs on the surface of one B cell all recognize the same antigen BCRs must be crosslinked for activation to occur

Which of these gene segments dictates the general class of an antibody:

C

IgG antibodies (check all that apply):

Can pass from the mother to a developing fetus in utero Help NK cells kill more effectively via ADCC Are effective at neutralizing viruses Have several different variants of their Fc regions, which allow subclasses to have different functions Are somewhat effective at fixing complement Are the longest-lived antibody class Are effective at opsonizing invaders for phagocytosis Contain 2 Fab regions Are in gamma globulin shots

As a B cell matures, it can change from making IgM-class antibodies to making IgE-class antibodies. The process by which this occurs is called:

Class switching

IgA antibodies (check all that apply):

Coat pathogens so they can be transported out of the body with feces Are unable to fix complement Are secreted in breast milk Can be transported across the intestinal wall Defend mucosal surfaces Contain 4 Fab regions Are the most abundant antibody in the human body Can prevent invaders from attaching to intestinal epithelium Ace resistant to acids and proteolytic enzymes in the digestive tract

The antigen that a B cell recognizes is called a(n):

Cognate antigen

The process by which C1 complexes are brought together to result in the loss of the C1 inhibitors is called:

Complement fixation

When B cell receptors are brought close enough together to cause B cells to be activated, the BRCs are said to be:

Crosslinked

Class switching is mediated by:

DNA splicing

IgE antibodies (check all that apply):

Defend against parasites Are produced upon exposure to an allergen Cause allergies Cause degranulation of mast cells

The specific 6-12 amino acid region of an antigen that binds to an antibody is called the:

Epitope

The portion of an antibody that determines how the antibody generally functions is the:

Fc region

Put the following steps in BCR construction in the proper order, from beginning to end:

Gene rearrangement occurs for the light chain Fifth step Productive rearrangement of the heavy chain is tested during translation Second step Gene rearrangement occurs for the heavy chain First step The light chain is tested for proper fit with the heavy chain Seventh step The heavy chain is transported to the B cell's plasma membrane Third step Productive rearrangement of the light chain is tested during translation Sixth step The B cell proliferates with only it's heavy chain Fourth step

Activated B cells can only become memory B cells with the help of:

Helper T cells

Mast cells granules contain primarily:

Histamines

The accessory protein portions of a BCR that are responsible for transmitting a signal inside the B cell that the Fab region has bound its antigen are:

Ig(alpha) and Ig(beta)

One effect that results from B cell receptors being cross-linked is that the:

Ig(alpha) and Ig(beta) portions of the BCR cause an intracellular signaling cascade

The antibody that is capable of forming a bridge between a natural killer cell and one of our own cells that is infected with a virus is:

IgG

The main classes of antibodies are (check all that apply):

IgG IgM IgA IgE

Which statements are true of polyclonal activation (check all that apply):

It does not require the BCR to bind to its cognate antigen It is an example of immune dysfunction It is dependent on mitogens

Which of the following correctly identifies the order of the construction of the heavy chain of the BCR:

One D and one J segment are joined together; one V segment is joined to the DJ segment; a C segment is joined to the VDJ segment.

As B cells mature, they can become (check all that apply):

Plasma B cells Memory B cells

Which method(s) of B cell activation do/does not require that BCRs bind to their cognate antigens:

Polyclonal activation

B cells can be activated in which of the following ways (check all that apply):

Polyclonal activation T cell-independent T cell-dependent

Class switching is characterized by:

Producing different classes of antibodies all of which recognize the same antigen

The element of the adaptive immune system that differentiates it from other parts of our immune response is its ability to:

Protect against nearly any kind of invader

The phenomenon in which high levels of rates of change occur in the DNA encoding V, D, and J gene segments is called:

Somatic hypermutation

The processes by which B cell populations become increasingly more effective at responding to a particular invader during the course of infection include:

Somatic hypermutation and class switching

Which method(s) of B cell activation require that BCRs bind to their cognate antigens (check all that apply):

T cell-dependent activation T cell-independent activation

If neither copy of chromosome 14 in a B cell successfully produces a productive rearrangement of the heavy chain:

The B cell commits suicide

Crosslinking of BCRs is defined as:

The clustering together of BCRs bound to their cognate antigens near each other on the plasma membrane

After B cells have been activated and have proliferated, maturation is characterized by one or more of the following stages (check all that apply):

The decision to become plasma B cells or memory B cells Class switching Somatic hypermutation

If a B cell produces a productive arrangement of both the heavy and light chain proteins, then:

The heavy and light chain must fit together properly, or the B cell commits suicide.

Which branch of the immune system usually identifies as invader as dangerous?

The innate immune system

Antibody class switching is controlled by:

The type of cytokines near the B cell

If segments of the genes used to make antibodies are not linked in frame properly during gene rearrangement:

Translation ceases and a useless protein fragment results

IgM antibodies (check all that apply):

Were the first class of antibody to evolve Are the largest of the antibodies Contain 10 Fab regions Are effective at neutralizing viruses Are the first class of antibodies made upon activation of naïve B cells Are highly effective at fixing complement

A B cell that has never bound to its cognate antigen is called (check all that apply):

a naïve B cell a virgin B cell

A B cell that has bound to its cognate antigen is called:

an experienced B cell

Anaphylactic shock is caused by:

degranulation of mast cells

Affinity maturation is the process by which B cells:

proliferate more effectively if they bind their cognate antigen with higher affinity