Chapter 43

Which of the following statements is not true?

A lymphocyte has receptors for multiple different antigens.

Which statement best describes the difference in responses of effector B cells (plasma cells) and cytotoxic T cells?

B cells secrete antibodies against a pathogen; cytotoxic T cells kill pathogen-infected host cells.

The ability of one person to produce over a million different antibody molecules does not require over a million different genes; rather, this wide range of antibody production is due to

DNA rearrangements.

Arrange these components of the mammalian immune system as it first responds to a pathogen in the correct sequence. I. Pathogen is destroyed. II. Lymphocytes secrete antibodies. III. Antigenic determinants from pathogen bind to antigen receptors on lymphocytes. IV. Lymphocytes specific to antigenic determinants from pathogen become numerous. V. Only memory cells remain.

III → IV → II → I → V

An immune response to a tissue graft will differ from an immune response to a bacterium because

MHC molecules of the donor may stimulate rejection of the graft tissue, but bacteria lack MHC molecules.

This type of immunity is present only when a newborn infant is being fed by actively nursing on its mother and ends when nursing ends.

Passive Immunity

A systemic inflammatory response that is often life-threatening is

Septic shock

A patient who can produce antibodies against some bacterial pathogens, but not against viral infections, probably has a disorder in his

T cells

Bacterial infection in a previously uninfected house cat would most quickly activate its

Toll-like receptors that bind to lipopolysaccharides.

Most newly emerging diseases result in

a destruction of the host's immune system and eventual cancer.

The complement system is

a group of antimicrobial proteins that act together in a cascade fashion.

A diseased patient is exposed to an unknown agent while out of the country. The patient's blood is found to have a high proportion of lymphocytes with CD8 surface proteins in her blood, a likely result of

a viral infection eliciting proliferation of CD8+ cytotoxic T cells.

Bacteria entering the body through a small cut in the skin

activate a group of proteins called complement.

Which of these is not part of insect immunity?

activation of natural killer cells

In some insects, such as Drosophila, fungal cell wall elements can activate the protein Toll, which

acts as a receptor that, when activated, signals synthesis of antimicrobial peptides.

Mutant fruit flies that make only one antimicrobial peptide were tested for survival after infection with Neurospora crassa fungi or with Micrococcus luteus The results shown in the graphs support the hypothesis that

adding the drosomycin gene to such mutants protects them from fungal infection.

Clonal selection is an explanation for how

an antigen can provoke production of high levels of specific antibodies.

In the human disease known as lupus, there is an immune reaction against a patient's own DNA from broken or dying cells, which categorizes lupus as A) an allergy.

an autoimmune disease.

A patient who has a parasitic worm infection and another patient responding to an allergen such as ragweed pollen have which of the following in common?

an increase in the levels of IgE

A patient who undergoes a high level of mast cell degranulation, dilation of blood vessels, and acute drop in blood pressure is likely suffering from

anaphylactic shock immediately following exposure to an allergen.

Among the last line of defenses against prolonged exposure to an extracellular pathogen is

antibody production by plasma cells.

The receptors on T cells and B cells bind to

antigens

Clonal selection implies that

antigens increase mitosis in specific lymphocytes.

A patient complaining of watery, itchy eyes and sneezing after being given a flower bouquet as a birthday gift should first be treated with

antihistamines.

Immunodeficiencies can be genetic in origin, and two examples are Bruton's agammaglobulinemia, an X-linked disorder, and DiGeorge syndrome, caused by a deletion from chromosome 22. Bruton's disorder results in underdeveloped B cells, whereas DiGeorge syndrome results in a missing or seriously underdeveloped thymus. Select the description that likely indicates a child with Bruton's disease.

baby boy Jeff, with no plasma cells following infection by bacterial pneumonia

A newborn who is accidentally given a drug that destroys the thymus would most likely

be unable to differentiate and mature T cells

According to the graph, naive B cells will produce effector cells

between 0 and 7 days.

B cells have antigen receptors that bind to antigens that are either freely dissolved or present on the surface of invading/foreign cells. T cells have antigen receptors that

bind to antigens presented on major histocompatability complexes by host cells

Preventing the appearance of the symptoms of an allergy attack would be the likely result of

blocking the attachment of the IgE antibodies to the mast cells.

Antihistamine treatment reduces

blood vessel dilation

Select the pathway that would lead to the activation of cytotoxic T cells.

body cell becomes infected with a virus → new viral proteins appear → class I MHC molecule-antigen complex displayed on cell surface

According to the graph, naive memory cells will be produced

both between 0 and 7 days and between 28 and 35 days.

According to the graph, antibodies will be produced

both between 3 and 7 days and between 28 and 35 days

After a long and cold winter, Jim was excited to start exploring the woods behind his new home. His first adventure included exposure to poison ivy without any reaction. A month later, though, a second walk through the woods was not so great, since two days later Jim had a terrible rash that lasted for weeks. The fact that the rash took two days to develop indicates that this immune response was an example of

cell-mediated immunity.

Septic shock, a systemic response including high fever and low blood pressure, is a response to

certain bacterial infections.

An otherwise healthy student in your class is infected with EBV, the virus that causes infectious mononucleosis. The same student had already been infected when she was a child, at which time she had merely experienced a mild sore throat and swollen lymph nodes in her neck. This time, though infected, she does not get sick. The EBV antigen fragments will be presented by the virus-infected cells along with

class I MHC molecules.

Which of the following cells are involved in cell-mediated immunity and also respond to class I MHC molecule-antigen complexes?

cytotoxic T cells

The cell-mediated immunity that destroys virally infected cells involves

cytotoxic T cells.

n otherwise healthy student in your class is infected with EBV, the virus that causes infectious mononucleosis. The same student had already been infected when she was a child, at which time she had merely experienced a mild sore throat and swollen lymph nodes in her neck. This time, though infected, she does not get sick. Her immune system's recognition of the second infection involves the

cytotoxic T cells.

T cells of the immune system include

cytotoxic and helper cells.

The MHC is important in a T cell's ability to

distinguish self from nonself.

Normal immune responses can be described as polyclonal because

diverse antibodies are produced for different epitopes of a specific antigen.

Mammals have Toll-like receptors (TLRs) that can recognize a kind of macromolecule that is absent from vertebrates but present in/on certain groups of pathogens, including viral

double-stranded RNA.

The number of MHC protein combinations possible in a given population is enormous. However, an individual in that diverse population has a far more limited array of MHC molecules because

each of the MHC genes has a large number of alleles, but each individual only inherits two for each gene.

A bone marrow transplant may not be appropriate from a given donor (Jane) to a given recipient (Jane's cousin Bob), even though Jane has previously given blood for one of Bob's needed transfusions, because

even though Jane's blood type is a match to Bob's, her MHC proteins may not be a match.

Antigens are

foreign molecules that trigger the generation of antibodies.

A cell type that interacts with both the humoral and cell-mediated immune pathways is a

helper T cell.

B cells interacting with helper T cells are stimulated to differentiate when

helper T cells release cytokines.

The ability of some viruses to remain inactive (latent) for a period of time is exemplified by

herpes simplex viruses (oral or genital) whose reproduction is triggered by physiological or emotional stress in the host.

An inflammation-causing signal released by mast cells at the site of an infection is

histamine

Antibodies of the different classes IgM, IgG, IgA, IgD, and IgE differ from each other

in their heavy-chain structure.

Inflammatory responses typically include

increased activity of phagocytes in an inflamed area.

Infection with HIV typically

increases the level of helper T cells for the first year after infection.

An individual who has been bitten by a poisonous snake that has a fast-acting toxin would likely benefit from

injection of antibodies to the toxin.

Acidity in human urine is an example of

innate immunity.

A nonfunctional CD4 protein on a helper T cell would result in the helper T cell being unable to

interact with a class II MHC-antigen complex.

The lymphatic fluid

is a filtrate of the blood, as is urine.

Innate immunity

is activated immediately upon infection.

A fruit fly, internally infected by a potentially pathogenic fungus, is protected by

its antimicrobial peptides.

Vaccination increases the number of

lymphocytes with receptors that can bind to the pathogen.

An invertebrate, such as an insect, has innate immunity activity in its intestine that likely includes

lysozyme

The function of antibodies is to

mark pathogenic cells for destruction.

Secondary immune responses upon a second exposure to a pathogen are due to the activation of

memory cells

CD4 and CD8 are

molecules present on the surface of T cells where they interact with MHC molecules.

Engulfing-phagocytic cells of innate immunity include all of the following except

natural killer cells

The cells involved in innate immunity, whose absence increases the chances of developing malignant tumors, are

natural killer cells.

An immunoglobulin (Ig) molecule, of whatever class, with regions symbolized as C or V, H or L, has a light chain made up of

one C region and one V region.

Adaptive immunity depends on

pathogen-specific recognition.

Naturally acquired passive immunity results from the

placental transfer of antibodies.

Which of the following would not help a virus avoid triggering an adaptive immune response?

producing proteins very similar to those of other viruses

Yearly vaccination of humans for influenza viruses is necessary because

rapid mutation in flu viruses alters the surface proteins in infected host cells.

Within a differentiated B cell, the rearrangement of DNA sequences between variable regions and joining regions is accomplished by

recombinase

Histamines trigger dilation of nearby blood vessels as well as an increase in their permeability, producing

redness, heat, and swelling

Clonal selection of B cells activated by antigen exposure leads to production of

short-lived plasma cells that secrete antibodies for the antigen.

Infection by a bacterium that has elements on its surface that enhance its resistance to lysozyme will likely result in

successful reproduction of the bacterium and continued progression of the disease.

Cave art by early humans recognized the existence of the major signs of inflammation. The most inclusive set of symptoms of inflammation that might appear in such early human art is

swelling, heat, redness, and pain.

An epitope is

that part of an antigen that actually binds to an antigen receptor.

Immunological memory accounts for

the ancient observation that someone who had recovered from the plague could safely care for those newly diseased.

Phagocytosis of microbes by macrophages is enhanced by

the binding of antibodies to the surface of microbes and antibody-mediated agglutination of microbes only.

Immunodeficiencies can be genetic in origin, and two examples are Bruton's agammaglobulinemia, an X-linked disorder, and DiGeorge syndrome, caused by a deletion from chromosome 22. Bruton's disorder results in underdeveloped B cells, whereas DiGeorge syndrome results in a missing or seriously underdeveloped thymus. Bruton's disorder will likely include

the failure of heavy-chain gene rearrangement in B cells.

An example of a pathogen that undergoes rapid changes resulting in antigenic variation is

the influenza virus, which expresses alternative envelope proteins.

The cells and signaling molecules that initiate inflammatory responses are

the mat cells and the histamines

Immunodeficiencies can be genetic in origin, and two examples are Bruton's agammaglobulinemia, an X-linked disorder, and DiGeorge syndrome, caused by a deletion from chromosome 22. Bruton's disorder results in underdeveloped B cells, whereas DiGeorge syndrome results in a missing or seriously underdeveloped thymus. Assume that a DGS-like phenotype was produced in a specific "gene-knockout" mouse, one lacking expression of HA3, a Hox gene known to be involved in developmental regulation in the mouse.

the measurement of the proportion of CD4 cells to total lymphocytes.

Salmonella bacterial poisoning can be initiated when

the microbe survives the acidic environment of the stomach and resists lysosomal degradation in macrophages.

When antibodies bind antigens, the clumping of antigens results from

the multivalence of the antibody having at least two binding regions.

Ancient peoples sought to identify the indicators of inflammation because

the presence of these signs suggests that healing was taking place; otherwise, the patient would likely die

A key part of the humoral immune response is

the production of antibodies by plasma cells

The switch of one B cell from producing one class of antibody to another antibody class that is responsive to the same antigen is due to

the rearrangement of immunoglobulin heavy-chain C region DNA.

The transfusion of type A blood to a person who has type O blood would result in

the recipient's anti-A antibodies clumping the donated red blood cells.

In active immunity, but not passive immunity, there is

the requirement for direct exposure to a living or simulated pathogen.

The eyes and the respiratory tract are both protected against infections by

the secretion of lysozyme onto their surfaces.

Which of the following should be the same in identical twins?

the set of MHC molecules produced

For the successful development of a vaccine to be used against a pathogen, it is necessary that

the surface antigens of the pathogen not change.

Jenner's successful use of cowpox virus as a vaccine against the smallpox virus is due to the fact that

there are some antigenic determinants common to both pox viruses.

The primary function of humoral immunity is

to protect the body against extracellular pathogens.

An epitope associates with which part of an antigen receptor or antibody?

variable regions of a heavy chain and light chain combined

The activation of helper T cells is likely

when an antigen is displayed by a dendritic cell.