Microbiology Ch 15 HW & Quiz

Select those the statements that correctly assess the relationship between MHC molecules and cell surface receptors

*class 2 MHC glycoproteins are found only on antigen-presenting cells: macrophages, dendritic cells, and B lymphocytes *Viral epitopes with an infected liver cell are presented by MHC 1 molecules and bind to cytotoxic T cell receptors *Dendritic cells possess both MHC 1 and MHC 2 glycoproteins that bind to cytotoxic and helper T cell receptors, respectively. *Class 1 MHC glycoproteins allow the presentation of foreign epitopes on all nucleated host cells

In the case of cancer or viral infection, which MHC class is involved with displaying abnormal proteins to cytotoxic T cells as a signal for destruction?

1

Components of APCs

1.) contain both MHC 1 and MHC 2 molecules 2.) dendritic cells and macrophages

Components of B lymphocytes

1.) contain both MHC 1 and MHC 2 molecules 2.) differentiate into memory cells 3.) produce antibodies

Components of T lymphocytes

1.) differentiate into memory cells 2.) contain clusters of differential 3.) cells produce perforin and granzyme

clonal selection theory steps

1.) during development of lymphocytes from stem cells, genetic recombination events create a variety of clones; cells with receptors that match "self" are eliminated from the population. 2.)Antigen specificity is set and programmed for the life of the cell; the large pool of naive cells awaits antigen stimulation 3.) Antigen is encountered by specific lymphocytes; selected clone undergoes mitotic division to create a larger population of identical cells

Select the characteristics exhibited by effective vaccines

1.) little or no adverse side effects 2.) protect against exposure to wile-type, natural pathogens 3.) stimulate either a B cell or a T cell response 4.) relatively long shelf life

Properties/characteristic of B Cells

1.) mature in bone marrow 2.) Immunoglobulin surface markers 3.) Located in the cortex of lymphatic organs 4.) do not require antigen presented with MHC 5.) Production of antibodies

Properties/characteristics of T Cells

1.) mature in the thymus 2.) CD molecules on surface 3.) Located in the paracortical sites of lymphatic organs 4.) Require antigen presentation with MHC 5.) Assist other immune cells, mediate hypersensitivity, synthesize cytokines

Helper T cells require antigen processing and presentation by MHC ______ molecules

2

Arrange the following in proper order in which they occur during clonal selection *1.) Helper T-Cells are activated 2.) Macrophages ingest Antigen 3.) B-cells differentiate into plasma cells and memory cells

2.) macrophages ingest Antigen 1.) Helper T cells are activated 3.) B-Cells differentiate into plasma cells and memory cells

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

Anamnestic response

In the bloodstream, bacterial antigens will first bind to antibodies presented on

B cells

All nucleated cells contain

Class I MHC

________ bind to this complex, and after receiving activation signals, secrete ________.

Cytotoxic T cells; perforin and granzymes

Dimer that is a significant component of mucus and secretions

IgA

Main functions is to serve as antigen receptor on B cell surface

IgD

Mediates allergic responses

IgE

Most prevalent antibody in cirulation

IgG

The immunoglobulin class that is the only one capable of crossing the placenta is

IgG

Pentameric is circulation

IgM

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

Interleukin-1

An activated TH cell produces ___ which is a growth factor for T helper cells and cytotoxic T cells.

Interleukin-2

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

Interleukin-2

Not all phagocytic cells are antigen-presenting cells. B cells, macrophages, and dendritic cells differ from neutrophils in that they synthesize

MHC-2 receptors

Which lymphocytes lack specificity for antigen and are cells that attack cancer cells and virus-infected cells?

Natural killer (NK) cells

Which process involves antibodies covering surface receptors on a virus or toxin molecule, thereby disrupting their activity?

Neutralization

Which of the following cells are needed for most B cells to become functional?

T helper cells

_______ bind to the complex and secrete _______ that stimulate differentiation into T helper 1 and 2 cells which in turn stimulate clones of cytotoxic T cells and B cells, respectively.

T helper cells; interieukins

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 you children. Which is an accurate statement that you physician may provide to you in response to your challenge to vaccination?

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.

You have received the first hepatitis A vaccine. It was required for your mission trip to Nicaragua in Central America, where hepatitis A is common. However, you never went back for the booster shot of the vaccine, which should have been received withing 6 months of the initial vaccination. What statement accurately reflect your present immunity to this pathogen?

You are at risk to get hepatitis A since your immune status is only partial. Not enough immune memory cells were produced since you received one dosage of vaccine, so you are likely to get the disease when exposed to the virus.

Vaccinia virus is often used in the technique to make

a "Trojan horse" recombinant vaccine.

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:

a primary immune response

When first administered to a naive individual (has not been exposed to measles virus), the measles vaccine will stimulate

a primary response

An individual successfully recovered from measles as a child. Now 35 years old, her toddler has the infection. What immune response is occuring in the woman's body at this time?

a secondary response

Major Histocompatibility Complex (MHC)

a set of genes that code for MHC glycoproteins

Which of the following is a special binding substance that enhances immunogenicity and prolongs antigen retention at the injection site?

adjuvant

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

agglunitation

MHC-1 molecules are located on what types of cells?

all nucleated cells

There are three types; MHC class 1 are found on ___________, while MHC 2 are found on ________ cells.

all nucleated; antigen-presenting

Antigens, such as viruses, exist within a host cell and are therefore inaccessible to ________.

anitibodies

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

antibodies

A foreign molecule that causes a specific immune response is a/an

antigen

Which of the following is a term that refers to a gamma globulin that can neutralize virulence factors secreted by Staphyloccous or Streptococcus strains, as in the case of TSS?

antitoxin

Characteristics of antigens include

are made up of many antigenic determinants (epitopes)

Antigens

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

T-cells

are responsible for cell-mediated immunity

Superantigens are

bacterial toxins that activate T cells at a 100 times greater rate than other antigens

Which of the following do NOT serve as antigen presenting cells? *B lymphocytes *Basophils *Macrophages *Dendritic cells

basophils

Destruction of lymphocytes with self specificity is called

clonal deletion

MHC class 3 are associated with _______ funtion.

complement

Antitoxins

confer passive immunity

Acellular vaccines and subunit vaccines

contain select antigenic components of a pathogen rather than whole cells or viruses.

After repeated exposure to foreign material, nonspecific immunity

continues to react the same way

Based upon the epidemiological evidence, the mode of transmission in this case was

direct contact

The molecular fragment on an antigen molecule that a lymphocyte recognizes and responds to is called a/an

epitope

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

epitopes; MHC-1

Epidemiologists determined that this outbreak could have been avoided if

everyone had been adequately vaccinated against measles

cytotoxic T-cells kill target cells by

exposing them to chemicals which induces apoptosis

Each B cell can react to many different types of antigens.

false

Each antigen has one epitope.

false

Fragments of foreign proteins are antibodies.

false

One antibody can bind multiple types of antigens.

false

The actual bacterium causes the development of the symptoms seen in TSS.

false

The monomer subunit of immunoglobulin molecules has all of the following EXCEPT *disulfide bonds between polypeptide chains *two identical light polypeptide chains *a variable and constant region on each polypeptide chain *two identical heavy polypeptide chains *four antigen binding sites

four antigen binding sites

An example of artificial active immunity would be

giving a person immune serum globulins to chickenpox virus after exposure of the disease

An example of artificial active immunity would be

giving a person immune serum globulins to chickenpox virus after exposure to the disease

Bacterial Cells

have many different epitopes, which each bind to specific antibodies

The _________ genes code for the MHC glycoproteins.

human leukocyte antigen

The specific immune response

involves memory of antigens from previous exposure

Cytotoxic T-cells know that a cell is infected because

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

Which of the statements below represents the correct order of events in the adaptive immune response?

lymphocyte development, antigen presentation, lymphocyte challenge, lymphocyte response

_______ with antigen fragments displayed on their surfaces are known as antigen-presenting cells (APCs).

macrophages

MHC-2 molecules are located on what types of cells

macrophages, dendritic cells, and B cells

Which of the following is NOT true of the antigen-independent period of lymphocyte development? *lymphocytes form from stem cells in the bone marrow *lymphocytes with specificity for self are destroyed *mature lymphocytes populate lymphatic organs and encounter antigens *random genetic rearrangements occur to produce different surface proteins receptors *may lymphocytes with different specificities are formed

mature lymphocytes populate lymphatic organs and encounter antigens

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

memory B-cells are produced during the first response

Specific immunity provides long-lasting protection through the production of

memory cells

Which of the following statements characterizes clonal selection in the process of antibody production?

one B cell type is selected to rpoduce one type of antibody

An individual antibody is made against

one epitope on the cell

The ability of TC cells to initiate apoptosis in virally-infected cells and cancer cells is dependent on their ability to produces _______ and _______ in the target cell membrane.

perforin, granzyme

Other pathogens may exist within the body, but not within a cell. They must be take 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.

phagocytosis, APC; MHC-2

B-cells differentiate into ______ which make antibodies.

plasma cells

The antibody-secreting progeny cells of a B-cell clone are called

plasma cells

What type of cells secrete antibodies?

plasma cells

During which response to the antigen do we display a latent period of no secretory antibody synthesis?

primary

The array of potential antibodies to the variety of possible antigens is amazing. Which statement explains this development?

recombination of genes coding for the variable regions of immunoglobulins occurs during the developmental stage of lymphocyte production.

MHC molecules are found on each of the following cells EXCEPT *epithelial cells *red blood cells *leukocytes *islet of Langerhans cells *eosinophils

red blood cells

plasma cells

secrete antibodies

class 1 MHC genes code for

self receptors recognized by T lymphocytes.

the third line of defense against foreign invader can be described as having _______ and ________.

specificity; memory

Which of the following is correct regarding antibodies?

they are proteins

Which of the following is NOT a property of B cells? *they mature in the bone marrow *they have receptors called immunoglobulins *they require antigen presented with MHC proteins *there are low numbers circulating in the blood * they produce plasma cells and memory cells

they require antigen presented with MHC proteins

Which of the following statements doe NOT represent the role of a cell marker in the third line of defense?

they serve as transcription factors to initiate antibody production

Which of the following statements does NOT represent the role of a cell marker in the third line of defense? *they serve as transcription factors to initiate antibody production *they serve as recognition factors for self and nonself molecules *they receive and transmit signals to coordinate the immune response *They are attachment sites for foreign molecules

they serve as transcription factors to initiate antibody production

Differences among the five antibody classes are due primarily to variations in the FC fragments

true

MHC-1 molecules normally display "self" proteins, those that are normally produced by a cell.

true

Viruses and self-proteins are examples of proteins produced inside of the cell

true