chapter 17


17-1. Compare and contrast adaptive and innate immunity.

~ Innate immunity: Defenses against any pathogen.
~Adaptive immunity: Induced resistance to a specific pathogen.


17-2. Differentiate humoral from cellular immunity.

Humoral: antibody mediated; control of freely circulating
pathogens; B cells mature in the bone marrow
Cellular: cell-mediated (T cells); control of intracellular
pathogens; T cells mature in the thymus


17-3. Define antigen, epitope, and hapten.

Antigen: substance that causes the body to produce specific
antibodies or sensitized T cells
Epitope: antigenic determinants on antigen; antibodies recognize and
interact with them
Hapten: antigen is combined with carrier molecules


17-4. Explain antibody function and describe the structural
and chemical characteristics of antibodies.

An antibody is a protein that your body produces which binds to the
surface of a foreign body, like a bacteria or virus, and prevents it
from actively damaging your body. Antibodies, generally bind other
proteins, and they will bind to specific portions of the proteins.
Antibodies have a number of functions, they can directly kill the
invader, or they can recruit cell to the
infection.Structure:Proteins = Immunoglobulins
(Ig)Monomeric Unit composed of:Light ChainHeavy
ChainFC end - binds to cellsFAB end - epitope binding site


17-5. Name one function for each of the five classes of antibodies

IgG: monomer; 80% of serum antibodies; enhance phagocytosis;
neutralize toxins and viruses; protect fetus and newborn
IgM: pentamer; 5-10% of serum antibodies; fix complement;
agglutinate microbes; first Ab produced in response to infection
IgA: dimer; 10-15% of serum antibodies; mucosal protection
IgD: monomer; 0.2% of serum antibodies; on B cells, initiate immune response
IgE: monomer; 0.002% of serum antibodies; allergic reactions; lysis
of parasitic worms


17-6. Compare and contrast T-dependent and T-independent antigens.

T-dependent: Ag presented with (self) MHC (major histocompatibility
complex) to Th cell; Th cell produces cytokines that activate the B cell
T-independent: Stimulate the B cells to make Abs


17-7. Differentiate plasma cell from memory cell.

Plasma cell: activated B cell differentiates in to a plasma cell;
manufacture specific antibodies
Memory cell: a long-lived B or T cell responsible for the memory,
or secondary response


17-8. Describe clonal selection

The development of clones of B and T cells against a specific
antigen; clonal deletion eliminates harmful B cells


17-9. Describe four outcomes of an antigen´┐Żantibody reaction.

1) Agglutination:
Causes antigens to clump
together - more easily
digested by phagocytes e.g.
2) Opsonization:
(from greek to cater)
Coat bacteria with
antibodies that enhance
ingestion and lysis by
phagocytes
3) Neutralization:
Block viruses from attaching to host receptors -
can neutralize toxins in a similar manner
4) Activation of Complement system:
IgG and IgM bind and allow C1 to bind and start
complement cascade. Lysis of the microbe
attracts phagocytes to the site of infection


17-10. Differentiate T helper, T cytotoxic, and T regulatory cells.

T helper cells: interact with an antigen before B cells interact with
the antigen; specifically TH2 cells, produce IgE antibodies
T Cytotoxic: recognizes endogenous antigens on the target's cell
surface that are combined w/ MHC
T regulatory cells: formerly known as suppressor T cells, are a
subpopulation of T cells which modulate the immune system, maintain
tolerance to self-antigens, and abrogate autoimmune disease


17-11. Define apoptosis.

The natural programmed death of a cell. The residual fragments are
disposed of by phagocytosis


17-12. Define antigen-presenting cell.

accessory cell is a cell that displays antigen complexed with major
histocompatibility complexes (MHCs) on their surfaces


17-13. Distinguish a primary from a secondary immune response.

Primary response: occurs after initial contact with AgSecondary
response: occurs after second exposure


17-14. Contrast the four types of adaptive immunity.

natural active - resulting from infection
natural passive - transplacental or via colostrum
artificial active - injection of vaccination
artificial passive - injection of Ab from someone who has recovered
from the dx