Microbiology - Ch.16

Question 1

What are the steps in the correct order of B cell activation & antibody synthesis?

Answer 1

1.) Programmed B cell binds to its specific antigen
2.) Antigen is broken down & displayed on the surface of the B cell by MHC-II receptors
3.) An activated helper T cell with same antigen specificity binds to the B cell’s MCH-II receptor/antigen fragment with its CD4 & T cell antigen receptor.
4.) The B cell becomes fully activated
5.) The B cell differentiates into plasma cells, memory cells, & regulatory cells
6.) Clonal expansion occurs where each differentiated B cell multiplies into a large population. Plasma cells secrete antibodies with specificity for the same antigen that triggered the activation of the B cell.

Question 2

B cells

Answer 2

 Mature in bone marrow
 Production of antibodies
 Located in the cortex of lymphatic organs
 Do not require antigen presented with MHC
 Immunoglobulin surface markers

Question 3

T cells

Answer 3

 Mature in the thymus
 Assist other immune cells, mediate hypersensitivity, synthesize cytokines
 Located in the paracortical sites of lymphatic organs
 Require antigen presentation with MHC
 CD molecules on surface

Question 4

The ______ _________ _______ genes code for the MHC glycoproteins.

Answer 4

human leukocyte antigen

Question 5

There are three types; MHC class I are found on __ ______, while MHC class II are found on ______-_________ cells.

Answer 5

all nucleated; antigen-presenting

Question 6

MHC class III are associated with _______ function.

Answer 6

complement

Question 7

Antigens, such as viruses, exist within a host cell & are therefore inaccessible to _________.

Answer 7

Antibodies

Question 8

Proteins that are produced by viruses are broken down, & fragments known as _____ are presented on the surface of the infected host cell in a complex with the ____ _ molecules.

Answer 8

epitopes; MHC I

Question 9

__________ _ ____ bind to this complex, & after receiving activation signals, secrete _______ & _________ to effectively kill the infected cell.

Answer 9

Cytotoxic T cells; perforin & granzymes

Question 10

Other pathogens may exist within the body, but not within a cell. They must be taking into the cell by the process of __________ so that the epitopes can be displayed on the surface of the ___ in a complex with the _____ __ molecules

Answer 10

phagocytosis; APC; MHC II

Question 11

_ _____ ___ bind to this complex & secrete _______ that stimulate differentiation into T helper 1 & 2 cells which in turn stimulate clones of cytotoxic T cells & B cells, respectively.

Answer 11

T helper cells; interleukins

Question 12

True or False: Clonal selection requires the presence of foreign antigens

Answer 12

True

Question 13

What is the line of defense that displays immunologic memory?

Answer 13

Third line defenses

Question 14

The first stage of the specific immune response involves…

Answer 14

lymphocyte development & differentiation

Question 15

What are the four main functions of cellular markers?

Answer 15

o Attachment to foreign antigens
o Binding to self molecules, including MHC
o Receiving & transmitting chemical signals
o Assisting in cellular development

Question 16

What is the phrase that describes MHC class I molecules?

Answer 16

expressed on all human nucleated cells

Question 17

True or False: B & T cells can only recognize & bind antigen that has been processed & presented on MHC molecules

Answer 17

False (B cells have Ig receptors that directly bind antigens; they can display these antigens on MHC II molecules. However, T cells have receptors that only bind antigens that have been processed & presented by MHC molecules).

Question 17

_________are substances that provoke a specific immune response which is so discriminating that only a single molecular fragment, called a/an _________, interacts with the lymphocyte’s receptor.

Answer 17

Antigens; epitope

Question 18

What statements accurately describes antigens?

Answer 18

o They are perceived as foreign
o Proteins are immunogenic antigens
o Antigens provoke an immune response

Question 19

Superantigens are potent stimulators of what cell type?

Answer 19

T cells

Question 20

What are the molecules that play a role in blood incompatibility & graft rejection?

Answer 20

Alloantigen

Question 21

What are the antigens that evoke an immediate hypersensitive response of the immune system?

Answer 21

allergens

Question 22

What is the immunogen that is a potent stimulator of T cells?

Answer 22

Superantigen

Question 23

Antigen presenting cells…

Answer 23

“all of these choices are correct”:
o Include dendritic cells
o Include macrophages
o Engulf & modify antigen to be more immunogenic
o Hold & present processed antigen on their cell membrane surface

Question 24

Which process involved antibodies cross-linking or particles into large aggregates?

Answer 24

agglutination

Question 25

Which method of cytotoxin T cell-mediated killing of a target cell?

Answer 25

apoptosis

Question 26

What is the coating of microbe with antibody to enhance phagocytosis?

Answer 26

Opsonization

Question 27

What are the antibodies that fill the surface receptors on microbes to prevent its attachment to the host

Answer 27

Neutralization

Question 28

What is the antibody that neutralizes bacterial exotoxins?

Answer 28

Antitoxin

Question 29

What is the cross-linkage of cells or particles into large clumps?

Answer 29

Agglutination

Question 29

Which antibody is the most prevalent antibody in circulation?

Answer 29

IgG

Question 30

Which antibody is dimer that is significant component of mucus & secretions?

Answer 30

IgA

Question 31

Which antibody is pentameric in circulation?

Answer 31

IgM

Question 32

Which antibody is that the main function is to serve as antigen receptor on B cell surface?

Answer 32

IgD

Question 33

Which antibody mediated allergic responses?

Answer 33

IgE

Question 34

True or False: Memory B cells are formed during the primary response so that upon a secondary antigen exposure, a faster & more vigorous antibody response ensues

Answer 34

True (the secondary response develops due to the presence of memory B cells at the time of re-exposure to an antigen. They allow for the rapid production of IgG in this response).

Question 35

True or False: Specific immune globulin (SIG) can be obtained from recovering patients and used for immunotherapy (artificial passive immunity).

Answer 35

True (SIG is preferable preparation for immunotherapy because of its higher antibody titer from a defined smaller group of donors).

Question 36

True or False: Effective vaccines should induce only B-cell responses in order to produce adequate long-term memory. -

Answer 36

False (effective vaccines should stimulate both B- & T-cell responses).

Question 37

What is not an example of a subunit vaccine?

Answer 37

Inactivate viruses

Question 38

What are examples of a subunit vaccine? -

Answer 38

products made by genetic engineering, bacterial toxins synthesized chemically in the laboratory, & molecules obtained from cultures of microbes

Question 39

What pertains to the principle of herd immunity?

Answer 39

o Immune individuals do not carry the agent of a particular communicable disease o Mass immunization confers indirect protection of non-immunized members o Low herd immunity means there are greater numbers of susceptible individuals

Question 40

The adaptive immune response…

Answer 40

involves memory of antigens from previous exposure.

Question 41

T cells

Answer 41

are responsible for cell-mediated immunity.

Question 42

Antigens….

Answer 42

are molecules that can be recognized by B- or T-cells.

Question 43

After repeated exposure to foreign material, innate immunity…

Answer 43

continues to react the same way _______ with antigen fragments displayed on their surfaces are known as antigen-presenting cells (APCs). -Macrophages

Question 44

When activated by antigen-presenting cells, helper T cells release what cytokine that activates B-cells & cytotoxic T-cells?

Answer 44

Interleukin-2

Question 45

Cytotoxic T-cells know that a cell is infected because..

Answer 45

it has antigens from the disease-causing microbe on its surface.

Question 46

PI

Answer 46

plasma cells

Question 47

The immune system responds more swiftly by making antibodies to an antigen after the first exposure because...

Answer 47

memory B-cells are produced during the first response

Question 48

Antigen-presenting cells release what cytokine to activate helper T-cells?

Answer 48

Interleukin-1

Question 49

A child with a genetic disorder that does not allow immature B-cells to develop would therefore not be able to make..

Answer 49

antibodies

Question 50

Cytotoxic T-cells kill target cells by..

Answer 50

exposing them to chemicals which induces apoptosis.

Question 51

_________ are molecules that stimulate a response by T-cells & B-cells.

Answer 51

antigens

Question 52

Surface receptors on immune system cells function in…

Answer 52

“all of these are functions of surface makers: identification of self/non-self, cell development, communication.

Question 53

T-cells…

Answer 53

stimulate B-cells & other T-cells.

Question 54

Cytotoxic T-cells recognize…

Answer 54

viral antigens & class I MHC

Question 55

Cytotoxic T-cells produce…

Answer 55

perforin, which makes holes in cell membrane of infected cells

Question 56

True or False: Cytotoxic T-cells directly kill the viruses found inside of infected cells.

Answer 56

False (cytotoxic T-cells produce cytotoxins which cause apoptosis, or death, of the actual infected).

Question 57

True or False: Self proteins of infected cells are not recognized by cytotoxic T-cells.

Answer 57

True (Cytotoxic T-cells do not recognize self proteins of infected cells)

Question 58

What cells can be a target for cytotoxic T-cells?

Answer 58

“all of these choices are correct”: viral-infected cells; transplanted cells; & cancer cells.

Question 59

True or False: In addition to apoptosis of infected host cells, apoptosis of lymphocytes also occurs during embryonic development

Answer 59

True (during the clonal deletion process, T-cells that react with self are destroyed by apoptosis).

Question 60

In addition to perforins, which chemical(s) is/are secreted by cytotoxic T-cells?

Answer 60

Granzymes

Question 61

True or False: A person deficient in cytotoxic T-cells may be more susceptible to cancer.

Answer 61

True (this is correct due to the role cytotoxic T-cells play in killing cancer cells).

Question 62

True or False: One plasma cell will secrete antibodies of various classes but the antibodies will all have different specificity

Answer 62

False (one plasma cell with secrete antibodies of various classes but the antibodies will all have the same specificity).

Question 63

Which process involved a more rapid synthesis & greatly increased titer of antibody when the immune system is subsequently exposed to the same antigen?

Answer 63

Anamnestic response

Question 64

Early in the primary response, most of the antibodies are the _______ type.

Answer 64

IgM

Question 65

True or False: An attenuated vaccine usually provides better immunity than a killed or inactivated one.

Answer 65

True (attenuated vaccines contain pathogens that are still able to multiply which provides more antigen, thus boosting the immune response).

Question 66

True or False: In a subunit vaccine, the subunit must come from the outer surface of the pathogen.

Answer 66

False (in a subunit vaccine, the subunit can be from either the outer surface of the pathogen or be an internal component).

Question 67

In creating a recombinant vaccine, a gene for an antigen can be spliced into a plasmid. What happens next?

Answer 67

The plasmid is placed into a host cell, such as yeast & the yeast will produce large quantities of the antigen.

Question 68

* COVID-19 vaccines are examples of _________ vaccines.

Answer 68

nucleic acid

Question 69

A toxoid would best be described as an example of which type of vaccine?

Answer 69

Subunit vaccine

Question 70

What is the purpose of booster shots?

Answer 70

to stimulate a secondary or anamnestic response.

Question 71

Live chickenpox virus can be used in a/an…

Answer 71

attenuated vaccine

Question 72

True or False: Vaccinations depend on the anamnestic response to successfully protect a person from infection.

Answer 72

True (vaccinations are designed to safely provide the first encounter with a weakened, dead or partial pathogen. The second exposure or memory response leads to a vigorous immune response.).

Question 73

Characteristics of antigens include:

Answer 73

are made up of many antigenic determinants (epitopes).

Question 74

Bacteria cells…..

Answer 74

have many different epitopes, which each bind to specific antibodies.

Question 75

An individual antibody is made against…

Answer 75

one epitope on the cell.

Question 76

True or False: Many different antibodies can be made against a single antigen

Answer 76

True

Question 77

Superantigens...

Answer 77

bind without antigen specificity to the outer portion of T helper cells & antigen presenting cells (APCs).

Question 78

Superantigens are produced by

Answer 78

Staphylococcus aureus in toxic shock syndrome

Question 79

Possible symptoms of toxic shock syndrome include…

Answer 79

“all of these choices are correct”: fever; diarrhea; nausea & vomiting, & shock

Question 80

True or False: Toxic shock syndrome is a mild disease similar to other mild allergic reactions

Answer 80

False

Question 81

True or False: Superantigens are processed by antigen presenting cells.

Answer 81

False

Question 82

You do not really want to get your 3 children vaccinated. Your view is why do it when others around you will get the vaccine and end up protecting you and your children. Which is an accurate statement that your physician may provide to you in response to your challenge to vaccination?

Answer 82

This is not a smart choice. If enough people choose not to get vaccinated, the susceptible population grows to a large size, breaking the protective effect of herd immunity.

Question 83

As an adult who never developed chickenpox infection as a child, you elect to receive the protective vaccine against this pathogen at the age of 35. This vaccine will stimulate…

Answer 83

a primary immune response

Question 84

The adaptive immune response differs from the innate response in that…

Answer 84

the adaptive immune response targets specific immunogens & remembers them, mounting an even stronger response on subsequent encounters, whereas the innate response is nonspecific & has no memory