Chapter 13 HW

Select the characteristics exhibited by effective vaccines.

- Little or no adverse side effects -Protect against exposure to wild-type, natural pathogens -Stimulate a B-cell or T-cell response -Relatively long shelf life

Lymphocyte's

A __________ capacity to discriminate differences in molecular shape is so fine that it recognizes and responds to only a portion of the antigen molecule.

Clonal selection

A conceptual explanation for the development of lymphocyte specificity and variety during immune maturation.

Acquired specific immunity

A dual system with B and T lymphocytes.

Titer

A measure or concentration of antibodies in a patient, determined by agglutination

Antitoxin

A special type of antibody that neutralizes bacterial exotoxins.

CD4

Accessory receptor protein mostly found on T helper cells that helps the T-cell receptor bind to MHC class II molecules.

Adaptive immunity

Acquired only after an immunizing event such as an infection.

Helper T cells ________

Activate B cells and other T cells

Helper T cells

Activate macrophages, B cells and T cells.

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

Adjuvant

Lymphocytes ________ have membrane receptors that recognize foreign antigens develop into clones of B and T cells with extreme variations of specificity All of the choices are correct gain tolerance to self by destruction of lymphocytes that could react against self possess MHC antigens for recognizing self

All of the choices are correct

Allergens

Antigens that evoke allergic reactions

All nucleated cells contain ________.

Class I MHC

When an antibody is covering the foreign microorganism then complement may be activated via this___ pathway.

Classical

What process provides many B cells and T cells that are activated against specific antigens?

Clonal expansion

B cells

Develop in the bone marrow. -As a result of gene modification and selection, hundreds of millions of distinct cells develop -These naive lymphocytes circulate through the blood, "homing" to specific sites in the lymph nodes, spleen, and other lymphoid tissue, where they adhere to specific binding molecules.

Latent period

Earliest part of the primary response. A lack of antibodies for that antigen, but much activity is occurring. Later, the class of the antibodies (but not their specificity) is switched to IgG or some other class (IgA or IgE).

Granzymes

Enzymes that attack proteins of target cells.

Mature T cells

Express either a CD4 or a CD8 coreceptor

Lymphocyte markers

Frequently called receptors

An example of artificial passive immunity would be

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

The immunoglobulin class that has a dimer form found in mucus, saliva, colostrum and other body secretions is

IgA

Which immunoglobulin class(es) can fix complement?

IgG and IgM

Isotypes

Immunoglobulins exist as structural and functional classes called __________ The classes are differentiated with shorthand names found in humans (Ig, followed by a letter: IgG, IgA, IgM, IgD, IgE).

Antigen-presenting cells (APCs)

In most immune reactions, the antigen must be formally presented to lymphocytes by cells called

Good immunogens

Large and complex.

Immunoglobulins

Large glycoprotein molecules that serve as the antigen receptors of B cells and, when secreted, as antibodies

Epitope

Lymphocytes recognize and respond to only a portion of the antigen molecule called

Antigens

Molecules that can be seen and identified by the immune system. -Can potentially any exposed or released protein or polysaccharide, even those on our own cells. - Can be perceived as foreign, meaning that it is not a normal constituent of the body.

CD8

Mostly found on cytotoxic T cells and it helps bind MHC class I molecules

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

Natural Killer Cells

Major histocompatibility complex (MHC)

One set of genes that codes for human cell markers or receptors

What type of cells secrete antibodies? The progeny cells of a B-cell clone are called ________

Plasma cells

Perforins

Proteins that can punch holes in the membranes of target cells.

The histocompatibility complex proteins function in

Recognition of self

Haptens

Small foreign molecules that are too small by themselves to stimulate the immune response. -Molecules as drugs, metals, and ordinarily innocuous household, industrial, and environmental chemicals

Bad immunogens

Small molecules, linear molecules, simple molecules, repetitive polymers

Superantigens

Some bacterial toxins, belong to a group of immunogens that are potent stimuli for T cells. -Their presence in an infection activates T cells at a rate 100 times greater than ordinary antigens.

Phagocytes

The elegance and complexity of immune function are largely due to lymphocytes working closely together with ____________

Antigen binding sites

The ends of the forks formed by the light and heavy chains contain pockets, these sites are highly variable in shape to fit a wide range of antigens.

Products of B Lymphocytes: Antibody Structure and Functions

The two "arms" that bind antigen are termed antigen binding fragments (Fabs), and the rest of the molecule is the crystallizable fragment (Fc), because it does not bind to the antigen & was the first to be crystallized in pure form. The basic immunoglobulin molecule is a composite of 4 polypeptide chains: a pair of identical heavy (H) chains and a pair of identical light (L) chains One light chain is bonded to one heavy chain, and the two heavy chains are bonded to one another with disulfide bonds, creating a symmetrical, Y-shaped arrangement.

Receptors

Their major role is to "accept" or "grasp" antigens in some form.

Variable (V) regions in antigen binding sites & Constant (C) regions,

This extreme versatility is due to _______________ where amino acid composition is highly varied from one clone of B lymphocytes to another, as a result of the gene rearrangements just discussed. The remainder of the light chains and heavy chains consist of _________________ whose amino acid content does not vary greatly from one antibody to another.

Principal activity of an antibody

To immobilize, call attention to, or neutralize the antigen for which it was formed.

Primary response

Upon the first exposure to an antigen, the system undergoes a primary response.

The region of each antibody molecule where amino acid composition is highly varied from one clone of B lymphocytes to another is the

Variable region

Secondary response

When the immune system is exposed again to the same immunogen within weeks, months, or even years ______________ occurs

A naive B lymphocyte has receptors bound to its surface that ________ have a variable region that is different to the variable regions of B cell-receptors embedded in other naive B lymphocytes is one of up to 10 trillion possible protein configurations due to genetic rearrangement are all specific for the same antigen All of the choices are true statements concerning B lymphocyte-receptors. will have the same variable region as the antibodies that will be secreted following a challenge by the corresponding antigen

are all specific for the same antigen

B cell-receptors are similar to T cell-receptors in that ________

both receptors have a variable and a constant region

Small foreign molecules that are too small by themselves to elicit an immune response are termed ________.

hapten

Edward Jenner's work involved

immunization using a related, less pathogenic organism to give protection against a more pathogenic one.

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

interleukin-2

T-cell-independent antigens

lipopolysaccharide from the cell wall of Escherichia coli polysaccharide from the capsule of Streptococcus pneumoniae molecules from rabies and Epstein-Barr virus.