Microbio Ch 13

In the case of a _____cell, it can differentiate into _______ cells which will activate ______ cells.

CD4; T helper 1; phagocytic

In contrast, ______ T-cell activation requires the action of ______ cells in order to differentiate into memory CD8 cells and activated CD8 cells.

CD8; T helper 1

Opsonization

Coating of microbe with antibody to enhance phagocytosis

T regulatory cell

Controls specific immune response; prevents autoimmunity; CD4 receptors expressed

Agglutination

Cross linkage of cells or particles in large clumps

T cytotoxic cell

Destroy a target foreign cell by lysis; involved in graft rejection, CD8 receptors expressed

IgA

Dimer that is a significant component of mucus and secretions

T helper cell 2

Drives B-cell proliferation; secretes IL-4, IL-5, and IL-13; CD 4 receptors expressed

Class II MHC receptors are not present on

red blood cells

(T/F) Superantigens are processed by antigen-presenting cells.

False

(T/F) There are no antigens that can stimulate B-cells directly.

False: Antigens that stimulate B cells directly are called T-cell independent antigens

(T/F) B and T cells can only recognize and bind antigen that has been processed and presented on MHC molecules

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 and presented by MHC molecules.

(T/F) Cytotoxic T cells directly kill the viruses found inside of infected cells.

False: Cytotoxic T cells produce cytotoxins which cause apoptosis, or death, of the actual infected cells.

Which of the following lymphocytes are affected by HIV?

Helper T cells (extra info: The severe depression of helper T cells in HIV accounts for the immunopathology of AIDS. This impacts cell-mediated as well as humoral immunity.)

Disulfide bonds

Holds polypeptide chains together

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

IgM

The injectable form of the influenza vaccine is an example of what type of vaccine?

Inactivated vaccine

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

Interleukin-1 (extra info: Interleukin 1 is one of several signals needed for an antigen-presenting cell to activate a helper T cell. The helper T cell then secretes interleukin-2 to activate other immune cells.)

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

Interleukin-2

IgD

Main function is to serve as antigen receptor on B-cell surface

IgE

Mediates allergic responses

IgG

Most prevalent antibody in circulation

What is the difference between natural and artificial immunity? Please give two examples of each type of acquired immunity.

Natural immunity is a term referring to immunity acquired through normal life experiences, not medical means. Examples include exposure to infectious disease, subclinical infection, placental transfer, or breast feeding. Artificial immunity is a term referring to immunity produced purposefully through medical procedures. Examples include vaccination and administration of passive immunotherapy.

Fc

Part of antibody involved in binding various cells and molecules of the immune response

IgM

Pentameric in circulation

T helper cell 17

Promotes inflammation; secretes IL-17; CD4 receptors expressed

Which of the following is most indicative of the development of AIDS from HIV?

Recurrent diseases (extra info: While nonspecific symptoms are common in HIV infection, the immunopathology of AIDS would be most apparent with the onset of recurrent infections. The extreme suppression of helper T cells affects specific immunity and inhibits the patient's ability to fight off otherwise benign invaders. A single occurrence of disease would indicate that the immune system is not yet fully suppressed.)

Hinge region

Region between FAb and Fc that allows swiveling of the FAb

Gamma-delta T cell

Respond to PAMPs like nonspecific cells do but also produce memory cells when activated

Complement binding sites

Site within Fc region

Superantigens are produced by

Staphylococcus aureus in toxic shock syndrome

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

Subunit vaccine

The principle behind vaccination is to

stimulate a primary response and a subsequent memory response that primes the immune system for future exposure to a specific pathogen. The immune response will be powerful and sustained if the organism is encountered in the future

In a patient with a thymus tumor, the proliferation of what type of lymphocyte may be affected? In a patient with bone marrow cancer, the proliferation of what type of lymphocyte may be affected?

T cells mature in the thymus and proliferation would likely be affected with a thymus tumor. B cells mature and thymocytes, the precursors to T cells, originate in the bone marrow so both B- and T-cell proliferation would likely be affected in a patient with a marrow tumor.

It may also differentiate into a ______ cell for B-cell activation, or ________ or T regulatory cells for modulation of the _______ response.

T helper 2; T helper 17; inflammatory

Proteins generally are _________ antigens.

T-cell dependent

T cells differentiate into the following subsets

TH1, TH2, TH17, TR or TC,

Correct the two errors in the following statement by a patient: "When my body is introduced to a foreign antibody, T cells produce antigens for immune response."

The corrected statement would be: "When my body is introduced to a foreign antigen, B cells produce antibodies for immune response."

A 5-year-old child presents to his primary care physician for his MMR (measles, mumps, and rubella) vaccine and influenza vaccine. What type of vaccine is represented by each of these? How do they differ in preparation and how does each ultimately stimulate immunity in the body?

The influenza vaccine is an example of an inactivated vaccine. The virus is cultivated and treated with heat or chemicals so that the virulence is destroyed but antigenicity is retained. When it is introduced to the body, the vaccine stimulates immunity but is not able to multiply. The MMR vaccine is an example of a live attenuated vaccine. It contains live microbes whose virulence has been eliminated by modifying growth conditions or manipulating genes. The vaccine microbes multiply and stimulate immunity without causing disease.

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

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

During lymphocyte development, the major histocompatibility complex (MHC) plays a role in

the recognition of self by the immune system and rejection of foreign tissue

What is the purpose of booster shots?

To stimulate a secondary or anamnestic response

(T/F) A helper T cell must be activated before it can stimulate a B cell to produce antibody.

True

(T/F) Both antigen-presenting cells and B cells have class II MHC receptors on their surface

True

(T/F) Helper T cells interact with target cells by recognizing antigens that are complexed with MHC proteins

True

(T/F) Self-proteins of infected cells are not recognized by cytotoxic T cells.

True

(T/F) In addition to apoptosis of infected host cells, apoptosis of lymphocytes also occurs during embryonic development

True: During the clonal deletion process, T cells that react with self are destroyed by apoptosis.

(T/F) Cell surface markers play important roles in the specific immune response, in the recognition of both self and nonself molecules.

True: Major functions of immune system markers are (1) attachment to nonself or foreign antigens; (2) binding to cell surface receptors such as MHC molecules for self-recognition; (3) coordinating the response through chemical messages; and (4) aiding in cellular development

(T/F) Memory B cells are formed during the primary response so that upon a secondary antigen exposure a faster and morevigorous antibody response ensues

True: The secondary response develops due to the presence of memory B cells at the time of reexposure to an antigen. They allowfor the rapid production of IgG in this response

(T/F) A person deficient in cytotoxic T cells may be more susceptible to cancer.

True: This is correct due to the role cytotoxic T cells play in killing cancer cells.

(T/F) Vaccinations depend on the anamnestic response to successfully protect a person from infection.

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.

One plasma cell will secrete antibodies of various classes but the antibodies will all have _______.

the same specificity

FAb

the two arms that bind to antigen

When a foreign antigen is introduced to the body, B cells and T cells respond in different ways. Briefly describe these responses.

With the introduction of an antigen, a T cell gives rise to helper, regulatory, or cytotoxic T cells. T cells provide cell-mediated immunity. B cells respond to an antigen by the release of antibodies.

T helper 1 cells

activate cell-mediated immunity and phagocytic cells resulting in delayed hypersensitivity reactions (extra info: T helper 1 (TH1) cells secrete tumor necrosis factor and interferon gamma and are responsible for delayed hypersensitivity reactions.)

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

antibodies.

What makes the third line of defense different than the first and second lines?

antigen specificity; development of memory

A helper T cell becomes activated by a(n) ________

antigen-presenting cell

_______ are substances that provoke a specific immune response which is so discriminating that only a singlemolecular fragment, called an __________, actually interacts with the lymphocyte's receptor

antigens; epitope

method of Tc cell-mediated killing of a target cell

apoptosis

An _________ usually provides better immunity than a killed or inactivated one.

attenuated vaccine

Live chickenpox virus can be used in a(n) ___.

attenuated vaccine

Superantigens

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

In a subunit vaccine, the subunit can be from

either the outer surface of the pathogen or be an internal component.

Cytotoxic T cells kill target cells by

exposing them to chemicals which induces apoptosis.

Possible symptoms of toxic shock syndrome include

fever, diarrhea, nausea and vomiting, shock

Helper T cells:

function in both cell-mediated and humoral immunity. (extra info: Helper T cells activate B cells and other T cells, and therefore, they are involved in both the cell-mediated and humoral arms of specific immunity.)

B-cell differentiation is stimulated by

interleukins.

Cytotoxic T cells know that a cell is infected because

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

Poor immunogens include

large, repetitive molecules.

Cytotoxic T cells recognize

viral antigens and class I MHC

The first stage of the specific immune response involves:

lymphocyte development and differentiation

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

macrophages

cell types that can serve as antigen-presenting cells.

macrophages; B cells; dendritic cells

What are the steps in clonal selection

1) Macrophages ingest antigen 2)Helper T cells are activated 3) B cells differentiate into plasma cells and memory cells

What are the steps of the process of T cell activation?

1)T-cell activation begins when an APC delivers antigen to a CD4 or CD8 T cell. 2)In the case of a CD4 cell, it can differentiate into T helper 1 cells which will activate phagocytic cells. 3)It may also differentiate into a T helper 2 cell for B-cell activation, or T helper 17 or T regulatory cells for modulation of the inflammatory response. 4)In contrast, CD8 T-cell activation requires the action of T helper 1 cells in order to differentiate into memory CD8 cells and activated CD8 cells. 5)Activated CD8 cells will mount a direct attack on target cells through the action of perforins, which punch holes in membranes, and granzymes, which then enter through these passageways.

T-cell activation begins when an ______delivers antigen to a CD4 or CD8 T cell.

APC

T helper cell 1

Activates the cell-mediated immunity pathway; secretes TNF and interferon gamma; responsible for delayed hypersensitivity; CD4 receptors expressed

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

MHC class I molecules are expressed

on all human nucleated cells

An antigen-presenting cell presents antigen to a helper T cell ____

on its surface using a class II MHC

Cytotoxic T cells produce

perforin, which makes holes in cell membrane of infected cells

Activated CD8 cells will mount a direct attack on target cells through the action of _______, which punch holes in membranes, and _________, which then enter through these passageways.

perforins; granzymes

B cells differentiate into ______, which make antibodies.

plasma cells

Neutralization

Antibodies fill the surface receptors on microbes to prevent its attachment to the host

Antitoxin

Antibody that neutralizes bacterial exotoxins

Vaccination provides what type of acquired immunity?

Artificial active immunity

Primary action of B cells

B cells undergo antibody production and secretion. (extra info: The consequence of antigen activation of B cells is the differentiation into plasma cells which secrete antibody with the same specificity as the original receptor into the surrounding tissues.)