Microbio: Ch. 15

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Mature T cells express ______.

CD4 coreceptors CD8 coreceptors

Either --------- or -------- coreceptors are expressed on mature T cells.

CD4; CD8

Upon activation, this T cell type mounts a direct attack on target cells.

CD8

The CD8 coreceptor is found on the surface of which cell type?

Cytotoxic T cells

The nursing baby receives IgA from the mother's milk which is critical for protection because ______.

- IgA protects the gastrointestinal tract from enteric pathogens - natural intestinal barriers are not yet developed - the infant is not yet producing IgA

Looking at the structure of an antibody, you will find ______.

2 identical heavy chains constant regions 2 identical light chains

When activated by antigen, CD----- T cells directly attack and kill the target cell.

8

HIV infects T helper cells and severely reduces their number. Which of the following do you expect as a result of this?

A reduced ability of cytotoxic T cells to be activated A reduced ability of B cells to be activated

In most specific immune responses, antigen must be processed and presented by which of the following?

APC's

T-cell dependent antigens, which are usually protein based, require recognition steps between the following cells and substances.

Antigen Lymphocytes Antigen presenting cells

MHC class II molecules are found on which of the following host cells?

B lymphocytes Dendritic cells Macrophages

Which is NOT a characteristic of the structure of an antibody?

four different polypeptide chains

Microbes enter the human body most frequently through the ________ and ________ mucosa.

gastrointestinal; respiratory

The CD4 coreceptor is expressed on T ----- cells.

helper

The antigen binding sites on an antibody molecule are ______.

highly variable

Which of the following are principal activities of antibodies with respect to their specific antigens?

immobilize neutralize unite with (bind) call attention to

Any clinical process that produces immunity in an individual is called a(n) ________.

immunization

------ is the ability of the body to react to a myriad of foreign substances.

immunocompetence

The ability of the body to react to a myriad of foreign substances is termed ________.

immunocompetence

---- are the chemical class of proteins to which antibodies belong.

immunoglobins

The class of proteins to which antibodies belong are ________.

immunoglobins

B cells are activated by chemical signals called ______ produced by macrophages and T cells.

interleukins

The three main antigen presenting cells are --------, as well as -------- and B cells.

macrophages; dendritic

Antigen-presenting cells that both process and present antigenic determinants on their surfaces include B-cells, ------- and dendritic cells.

macrophanges

Chemical signals produced by ----- and T cells called interleukins can activate B cells.

macrophanges

One set of genes that codes for human cell receptors and plays a role in recognition of self by the immune system is the ---------- ---------- ------------ (MHC).

major histocompatibility complex

---- T or B cells remain for long periods to be ready to respond to the same antigen encountered at a later time.

memory

Some specific immune cells can differentiate into --------- cells, which persist long after a pathogen has been cleared and can reactivate during re-infection.

memory

The ______ response to previously seen antigens is the basis for the success of vaccinations.

memory

The basis of immunization is using antigen to produce immunologic ----- to that antigen.

memory

These cells remain in circulation for long periods of time and are ready to respond to a specific antigen should it be encountered again.

memory cells

Which of the following is a cell type that remains in the body long after a pathogen has been cleared, and can quickly respond if the body ever re-encounters the same pathogen?

memory cells

After an initial exposure to antigen, which of the following is not a typical time period for the generation of a secondary immune response?

minutes

----- immunity is acquired from infection or through breastfeeding from the mother; this immunity is acquired through normal life experiences.

natrual

Any immunity that is acquired during the normal biological experiences of an individual, such as infection or through breast feeding is known as ________ immunity.

natrual

After recovery from an infectious disease, the resistance to reinfection is called ________ immunity.

natural active

Recovery from infectious disease results in ------ --------immunity.

natural active

______ immunity can last from a few months to a lifetime.

natural active

Prenatal and postnatal mother and child relationships result in ----------- -------- acquired immunity.

natural passive

Which of the following is LEAST likely to show a similar combination of class I MHC genes?

neighbors from unrelated families

After antigen stimulation, B cells produce antibodies to ______ antigens.

neutralize inactivate target

T-cell dependent antigens do NOT require recognition steps between which of the following cells or substances?

neutrophils

The coating of nonself molecules with antibodies to increase their rate of phagocytosis is called ------

opsonization

---- immunity is the acquisition of premade antibodies either from the mother or via injection of immune serum.

passive

Specific resistance that is acquired indirectly by donation of preformed immune substances (antibodies) produced in the body of another individual is called artificial ________ immunity.

passive

Which is NOT a B cell outcome following activation signals from a T cell?

phagocytosis

Upon antigen encounter, B lymphocytes differentiate into antibody producing cells called ----- cells and memory cells that can quickly react with the same antigen in a subsequent encounter.

plasma

An antigen _______ cell is a cell that ingests and degrades an antigen and subsequently places the antigenic determinant molecules on its surface for recognition by CD4 T lymphocytes.

presenting

The ----- immune response is the initial antibody response upon encountering antigen.

primary

The first response of the immune system when exposed to an antigen is called a ________ immune response.

primary

Different host cell surface receptors can be involved in a wide range of significant roles such as ______.

promoting recognition of self antigens attachment to foreign antigens receiving and transmitting chemical messages aiding in cellular development

A given host cell can express several different surface molecules called ________, each of which has a role in detection, recognition, and cell communication.

receptors

An APC and a T cell form a complex between their ________ that triggers T cell activation.

receptors

During T cell activation, the APC and the T cell form a complex between their ----- that triggers T cell activation.

receptors

Microbes enter the body most frequently through the ------ tract or the ------- tract.

respiratory; gastrointestinal

The ---- response, also called the anamnestic response, is the specific immune response generated upon subsequent exposure to a previously seen antigen and it is directed by memory cells.

secondary

The ______ immune response is advantageous because it is faster and more vigorous at clearing antigen.

secondary

The advantage of a(n) ----- immune response is that it is faster and more vigorous at clearing antigen than the primary immune response.

secondary

The rapid rise in antibody titer following a repeat exposure to an antigen that has been recognized from a previous exposure is called a(n) ________ immune response.

secondary

The specific immune response is highly ------ which means that a given antibody, B cell receptor, or T cell receptor only recognizes a specific antigen.

selective

MHC class I proteins allow for the recognition of ----- molecules.

self

A given host cell can express ______.

several types of receptors

The two features that characterize the specific immune response are ---- and --------

specificity; memory

Which of the following is NOT a feature that characterizes specific immunity:

speed

The overall structure of an antibody is a(n) ______ shape.

symmetrical Y

Specific immunity is highly selective which means that antibodies produced to a specific foreign protein antigen on a virus only recognize ______.

that specific antigen

Cytotoxic T cells (with CD8 receptors) recognize antigen presented with MHC class ------ molecules

I

Helper T cells (with CD4 receptors) recognize antigen presented with MHC class ---- molecules.

II

Which of the following is NOT a reason why IgA from mother's milk is critical for the protection of a nursing baby?

IgA is needed to stimulate the baby's immature B cells

----- is any clinical procedure that produces either passive or active immunity in a subject.

Immunization

After antigen-presenting cells process an antigen, it is moved to the surface and then bound to ------- molecules for presentation.

MHC

Host cell protein receptors involved in immune reactions recognize self proteins such as -------- molecules.

MHC

What is the name for molecules that, following antigen processing, bind the antigen fragment and display it on the surface of the cell?

MHC

What is the set of genes that encodes human cell receptors that play a role in recognition of self by the immune system called?

MHC

Which type of protein must be complexed with peptide to activate CD8 T cells?

MHC class I protein

Which type of protein must be complexed with peptide to activate CD4 T cells?

MHC class II proteins

Which of the following are the main antigen-presenting cells?

Macrophages B cells Dendritic cells

Which of the following must be true if a newborn infant was found to have circulating antibodies against a pathogen it has never seen?

Mother's antibodies are able to cross the placenta

---- immunity is acquired from infection or through breastfeeding from the mother; this immunity is acquired through normal life experiences.

Natural

________ immunity occurs only as a result of prenatal and postnatal mother and child relationships.

Natural passive

______ enhances phagocyte recognition by coating the invader with antibodies so that they will be more readily recognized by phagocytes.

Opsonization

________ are differentiated B cells that produce and secrete large amounts of antibodies.

Plasma

------ cells are responsible for cell-mediated immunity.

T

Cytotoxicity is the ability for this type of lymphocyte to kill specific target cells.

T

____ cells are the "mediators" of cell-mediated immunity.

T

Which immune system cell assists in activating both B cells and T cells?

T helper cell

Assisting in the recognition steps of the T-cell response, which type of cell has a receptor that binds with the class II MHC receptor on the APC and with the antigen?

T helper cells

The CD4 coreceptor is found on the surface of which cell type?

T helper cells

Which cell types are needed to activate B cells in the absence of B cells activating independently?

T helper cells

Which of the following cell types does not express MHC class II molecules on its surface?

T lymphocytes

Antigen binding sites are considered to be highly ------- in amino acid sequence and thus shape.

variable

MHC class I molecules on host cells display unique characteristics of self which is important to the process of _____.

tissue recognition

An antibody has a symmetrical ----- shape.

Y

B and T lymphocytes provide protection against specific antigens as part of ------ immunity.

acquired

The third line of defense, also known as ________ immunity provides long-term protection against foreign antigens encountered through infection or vaccination.

acquired adaptive

Natural ----- immunity generates memory so it can last from a few months to a lifetime.

active

The result of the body's response to exposure to antigen is called ________ immunity.

active

----- immunity is the result of the body's response to antigen.

activite

---- is the process by which the crosslinking of antibodies and microbes renders the microbes immobile and enhances their phagocytosis.

agglutination

----- is the aggregation formed by antibodies binding cellular antigens or large particles.

agglutination

Crosslinking of antibody to microbes leads to ______, which renders microbes immobile and enhances their phagocytosis.

agglutination

The aggregation (or clumping) by antibodies of whole cells or similar-sized particles is called ________.

agglutination

A(n) ------- is a type of antigen that provokes an allergic response.

allergen

An antigen that provokes an allergic reaction is called a(n) ________.

allergen

Antigen binding sites are highly variable from one antibody to another. This is due to high variability of the ------ acid content that makes up the hypervariable region.

amino

The high level of variability in antigen binding sites of different antibodies is due to high variability of the ________ composition (sequence) that makes up the variable region.

amino acid

Activated B cells (plasma cells) secrete immunoglobulins otherwise known as -------

antibodies

Plasma B cells produce -----

antibodies

Plasma cells produce copious amounts of ________.

antibodies

Plasma cells secrete immunoglobulins called ________.

antibodies

While the newborn is developing its own specific immune response it is protected by ______.

antibodies obtained by nursing antibodies obtained in utero

Following stimulation by antigen, B cells differentiate either into plasma cells, which produce and secrete --------, or into ------- cells, which will react rapidly if the antigen is encountered at some point in the future.

antibodies; memory

A molecule that induces a specific immune response is known as a(n) __________.

antigen

Once naive B cells have homed in on and attached to secondary lymphoid tissues, they are able to come into contact with ________ that enters from circulation or fluids.

antigen

The principal activity of an antibody is to unite with, immobilize, call attention to, or neutralize the ----- which is complementary to its receptor.

antigen

In most specific immune responses, antigen must be processed and presented by ___________-__________ cells.

antigen-presenting

----- are foreign molecules that elicit a specific immune response.

antigens

--- immunity results when a person is given a vaccination or receives premade antibodies through medical intervention.

artificial

Immunity that is induced as a medical intervention, either by exposing an individual to an antigen or by administering an immune substance such as antiserum is called ________ immunity.

artificial

Immunotherapy is ----- passive immunization with antibodies.

artificial

Most antibodies are passed in utero, but ----- also provides milkborne antibodies.

breastmilk

The CD8 coreceptor is expressed on ------ T cells.

cytotoxic

---- is the ability of certain T cells to kill a specific target cell such as an infected cell or a cancer cell.

cytotoxicity

True or false: After B cells have homed in on secondary lymphoid tissues, they are available to bind antigens that enter from circulation or fluids.

true

Along with B cells, ______ can serve as APCs for T cell activation.

dendritic cells and macrophages

Antigens can be presented to T cells by B cells, ------ cells and -------

dendritic; macrophages

Activation signals received from the T cells cause the activated B cell to ______.

differentiate enlarge proliferate

A(n) ------- is any molecule or fragment of a molecule that has the potential to trigger a specific immune response.

epitope

The precise molecular group of an antigen that defines its specificity and triggers an immune response is called a(n) _____.

epitope

True or false: A given host cell can express only one type of receptor.

false

True or false: Maternal antibodies are unable to cross the placental barrier.

false

True or false: Immune system receptors are involved in binding to MHC molecules.

true

An important characteristic of an antigen is that it be perceived to be ________.

foreign

Antigens are ________ molecules that stimulate a specific immune response.

foreign

Due to individual differences in the inheritance of class I MHC genes, the cells of each individual express molecules that are -------- to other humans.

foreign

One important characteristic of an antigen is that it be perceived as -------- meaning that it is not a normal constituent of the body.

foreign

A secondary immune response can occur ______ after exposure to antigen.

years weeks months


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