Microbiology Chapter 15: Specific Immunity and Immunization

Site within Fc region

Complement binding site

Holds polypeptide chains together

Disulfide bonds

All of the following cells have class II MHC receptors on their surface EXCEPT ______. dendritic cells macrophages red blood cells B cells

red blood cells

Choose the phrase that describes MHC class I molecules. Are secreted from all human nucleated cells Are proteins involved in the complement system Expressed on all human nucleated cells Found on only some types of white blood cells

Expressed on all human nucleated cells.

The two arms that bind to antigen

Fab

T/F: APCs present antigens on CD8 molecules.

False

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

False

T/F: B-cell receptors are much smaller than T-cell receptors.

False

T/F: Cytotoxic T-cells directly kill the viruses found inside of infected cells.

False

T/F: Each antigen has one epitope.

False

T/F: T cell maturation requires stimulation from cells of the bone marrow.

False

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

False

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

Fc

Region between Fab and Fc that allows swiveling of the Fab

Hinge region

Superantigen Immunogen that is a potent stimulator of T cells Antigens that evoke an immediate hypersensitive response of the immune system Molecules that play a role in blood incompatibility and graft rejection

Immunogen that is a potent stimulator of T cells

Antigen-presenting cells release what cytokine to activate helper T-cells? Interleukin-1 Leukotrienes Interferon Interleukin-2

Interleukin-1

When activated by antigen-presenting cells, helper T-cells release what cytokine that activates B-cells and cytotoxic T-cells? Leukotrienes Interleukin-2 IgD Interleukin-1

Interleukin-2

An APC may also activate a CD8 T cell when the antigen is complexed with ___. These CD8 cells are called ___ T cells.

MHC-1, cytotoxic

_______ with antigen fragments displayed on their surfaces are known as antigen-presenting cells (APCs). Plasma cells Macrophages Cytotoxic T-cells Helper T-cells

Macrophages

Alloantigen Immunogen that is a potent stimulator of T cells Antigens that evoke an immediate hypersensitive response of the immune system Molecules that play a role in blood incompatibility and graft rejection

Molecules that play a role in blood incompatibility and graft rejection

Antibodies are produced by ______.

Plasma B cells

Select all of the characteristics shared by both B- and T-cell receptors. Receptors are formed by genetic recombination. These receptors contain only constant regions. Receptors are inserted into the cell membrane. The antigen binding site formed by one polypeptide chain. B and T cell receptors are also secreted from an activated cell.

Receptors are formed by genetic recombination. Receptors are inserted into the cell membrane.

Select the statements that accurately characterize T-cell activation. CD8 cells are stimulated by antigen bound to MHC II molecules. T helper cells play a role in B-cell activation. CD4 cells are stimulated by antigen bound to MHC II molecules. TH17 cells lead to the development of inflammatory reactions. Activation of CD4 T cells leads to the development of TC cells only.

T helper cells play a role in B-cell activation. CD4 cells are stimulated by antigen bound to MHC II molecules. TH17 cells lead to the development of inflammatory reactions.

Select the type of T cell that plays a role in dampening down an immune response. TH1 TH17 TC TREG

TREG

Select the statements that accurately reflect the process of antigen binding of B and T cells. The antigen receptor on a B cell is an antibody molecule. Class II MHC molecules are found on T cells. Antigen binding in both B and T cells is nonspecific. T cells bind antigen that has been processed and presented by MHC.

The antigen receptor on a B cell is an antibody molecule. T cells bind antigen that has been processed and presented by MHC.

Select the statements that accurately describe antigens. They are perceived as foreign. Only whole microbes can serve as antigens. Proteins are immunogenic antigens. Antigens provoke an immune response.

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

Select the line of defense that displays immunologic memory. First line defenses Second line defenses Third line defenses Nonspecific line defenses

Third line defenses

During lymphocyte development, the major histocompatibility complex (MHC) plays a role in driving protein synthesis in cytotoxic T-cells. stimulating plasma cells to produce more antibodies. allowing viruses to inject DNA or RNA into host cells. the recognition of self by the immune system and rejection of foreign tissue.

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

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: Cell surface markers play important roles in the specific immune response for the recognition of both self and nonself molecules.

True

T/F: Helper T-cells interact with target cells by recognizing antigens that are complexed with MHC proteins.

True

T/F: Lymphocytes possess a repertoire of about 500 genes that undergo genetic rearrangement and are expressed to create an almost unlimited number of unique antigen receptors.

True

T/F: Many different antibodies can be made against a single antigen.

True

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

T/F: Proteins generally are T-cell dependent antigens.

True

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

True

Select the targets of TC cells. Virally infected cells Cancer cells NK cells Cells transplanted from other animals or humans Bacterial cell walls

Virally infected cells Cancer cells Cells transplanted from other animals or humans

A child with a genetic disorder that does not allow immature B-cells to develop would therefore not be able to make ______. interleukin-2 interleukin-1 antibodies bradykinin

antibodies

A helper T-cell becomes activated by a(n) ______. antigen-presenting cell memory cell B-cell plasma cell

antigen-presenting cell

Characteristics of antigens include have molecular weights of around 1000. have one antigenic determinant (epitope). are considered normal by the immune system. are made up of many antigenic determinants (epitopes). are usually made of lipids.

are made up of many antigenic determinants (epitopes).

Antigens are molecules that can be recognized by B- or T-cells. are only found inside or on the surface of microbes. refers to any molecule found inside the body. are universal molecules shared by many microbes.

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

T cells arise and finish development in the bone marrow. all carry out the same function. make antibodies. are responsible for cell-mediated immunity.

are responsible for cell-mediated immunity.

After repeated exposure to foreign material, nonspecific immunity continues to react the same way. begins to react less strongly. involves a wider range of cells and mediators. reacts more quickly and intensely.

continues to react the same way.

Cytotoxic T-cells kill target cells by exposing them to alpha-interferon. activating C5 and forming the membrane attack complex. ingesting the target cell and exposing it to peroxides or chloride ions. exposing them to chemicals which induces apoptosis.

exposing them to chemicals which induces apoptosis.

Helper T-cells function only in humoral immunity by secreting antibodies. function in only cell-mediated immunity. function in both cell-mediated and humoral immunity.

function in both cell-mediated and humoral immunity.

Bacterial cells have one identifiable antigen that binds antibody. have two epitopes per cell. have many different epitopes, which each bind to specific antibodies. have many different epitopes, which all bind to the same antibody. are not antigenic.

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

B-cell differentiation is stimulated by ______.

interleukins

The specific immune response is the second line of defense after anatomical and chemical barriers. involves memory of antigens from previous exposure. involves millions of B and T cells - each individual cell can recognize many different antigens. is the first line of defense in the immune system.

involves memory of antigens from previous exposure.

Cytotoxic T-cells know that a cell is infected because there are high levels of cAMP near its surface. it has antigens from the disease-causing microbe on its surface. it releases small signaling carbohydrates. C3b is bound to its surface.

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

Characteristics of good antigens include all of the following EXCEPT ______. exotoxins whole cells large, repetitive molecules viruses

large, repetitive molecules

Cytotoxic T-cells recognize fragments of self proteins on infected cells. viral antigens and class II MHC. viral antigens and class I MHC. receptors on B cells.

viral antigens and class I MHC.

Order the following steps of clonal selection and expansion from the first step to last step. A specific lymphocyte is stimulated by its specific antigen. B cells mature in the bone marrow and T cells mature in the thymus, meaning they build a unique antigen receptor based on genetic recombinations. Bone marrow stem cells differentiate into lymphocytes. That lymphocyte undergoes mitotic division, forming a large population of cells with the same specificity. Lymphocytes migrate to secondary lymphoid tissues.

1. Bone marrow stem cells differentiate into lymphocytes. 2. B cells mature in the bone marrow and T cells mature in the thymus, meaning they build a unique antigen receptor based on genetic recombinations. 3. Lymphocytes migrate to secondary lymphoid tissues. 4. A specific lymphocyte is stimulated by its specific antigen. 5. That lymphocyte undergoes mitotic division, forming a large population of cells with the same specificity.

Correctly order the overall steps of a primary and a secondary immune response. Latent period First exposure to antigen Second exposure to antigen IgM produced, followed by IgG production Anamnestic response; IgG is major class of antibody synthesized

1. First exposure to antigen 2. Latent period 3. IgM produced, followed by IgG production 4. Second exposure to antigen 5. Anamnestic response; IgG is major class of antibody synthesized

CD4 helper T cells may also differentiate into T helper ___ cells for B-cell activation, or T helper ___ or T regulatory cells for modulation of the ___ response.

2, 17, inflammatory

Arrange the following in the 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.

B cells differentiate into plasma cells and _______. memory cells macrophages helper T-cells mast cells

memory cells

T-cell activation begins when an ___ presents an antigen fragment in association with an MHC-II molecule to a ___ helper T cell.

APC, CD4

Choose the phrase that best describes T helper 1 (TH1) cells. Destroy foreign target cells Activate phagocytic cells resulting in delayed hypersensitivity reactions Drive B cell proliferation Possess a CD25 cell surface receptor

Activate phagocytic cells resulting in delayed hypersensitivity reactions

Antigen presenting cells include macrophages. include dendritic cells. engulf and present processed antigen on the surface. All of these are correct.

All of these are correct.

An antigen-presenting cell presents antigen to a helper T-cell on its surface attached to an antibody. inside a vesicle. on its surface using a class II MHC. on its surface using a class I MHC.

on its surface using a class II MHC.

An individual antibody is made against

one epitope on the cell

Cytotoxic T-cells produce interferon which attacks viral-infected cell. perforin, which makes holes in cell membrane of infected cells. class II MHC which present antigens. antibodies, which make holes in cell membrane of infected cells.

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

Once activated, helper T cells can differentiate into T helper 1 cells which will activate ___ cells and secretes IL-2 to help activate cell mediated immunity.

phagocytic

B-cells differentiate into ______, which make antibodies. cytotoxic T-cells macrophages helper T-cells plasma cells

plasma cells

The antibody producing progeny cells of a B-cell clone are called _______. sensitized T-cells bursa cells plasma cells antibodies

plasma cells

Allergen Immunogen that is a potent stimulator of T cells Antigens that evoke an immediate hypersensitive response of the immune system Molecules that play a role in blood incompatibility and graft rejection

Antigens that evoke an immediate hypersensitive response of the immune system

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

Antigens, epitope

Choose the statement that best describes the primary action of B cells. B cells produce interleukin-2, a lymphocyte growth factor. B cells interact with antigen on antigen presenting cells. B cells become active in cell-mediated immunity. B cells undergo antibody production and secretion.

B cells undergo antibody production and secretion.