Chapter 17

Question 1

humoral immunity

Answer 1

Immunity produced by anitbodies dissolved in body fluids, mediated by B cells; also called antibody

Question 2

thymus

Answer 2

a mammalian organ responsible for the maturation of the immune system.

Question 3

B cell

Answer 3

a type of lymphocyte; differentiates into antibody-secreting plasma cells and memory cells. They mature in the bone marrow and recognize an antigen and build antibodies against them.

Question 4

T cells

Answer 4

A lymphocyte which develops from a stem cell processed in the thymus gland, that is responsible for cell-mediated immunity.

Question 5

TCR- T cell receptor

Answer 5

Molecules on a T cell that recognize antigens

Question 6

antigen

Answer 6

any substance that causes antibody formation. they are usually large polysaccharides or proteins.

Question 7

epitope/ antigenic determinant

Answer 7

a specific region on the surface of an antigen against which antibodies are formed.

Question 8

hapten

Answer 8

a substance of low molecular weight that does not cause the formation of antibodies by its self but does so when combined with a carrier molecule.

Question 9

antibodies

Answer 9

a protein produced by the body in response to an antigen and capable of combining specifically with an antigen.

Question 10

Immunoglobulin (Ig)

Answer 10

a protein antibody formed in response to an antigen and can react with that antigen.

Question 11

Can a bacterium or virus have more than one epitopes?

Answer 11

yes. a bacterium or virus may have several epitopes that cause the production of different antibodies

Question 12

antigen binding sites

Answer 12

a site on an antibody that binds to an antigenic determinant. each antibody has at least two binding sites

Question 13

monomer

Answer 13

the simplest molecular structure of an antibody; bivalent;four protein chains; 2 identical heavy chains and 2 identical light chains

Question 14

variable regions

Answer 14

the two ends of the “Y” that bind to the epitopes s

Question 15

constant region/Fc region

Answer 15

the stem of the “Y” antibody. they are the same for a particular class of immunoglobin/antibody

Question 16

IgG

Answer 16

monomer; located in the lymph, blood, intestines; they enhance phagocytosis;neutralize toxins and viruses, and protect fetus and newborns since they can cross the placenta; they make up 80%; they readily cross the blood vessels and enter tissues; does activate the complement fixation

Question 17

IgM

Answer 17

five monomers held together by a J chain; located in the blood, and B cell surface; they are so large they usually dont leave the blood ; especially effective against microorganisms and agglutinating antigens; first antibodies produced in response to an initial infection; can cause complement fixation

Question 18

IgA

Answer 18

a dimer with a secretory complement; located in the secretions (tears, saliva, mucus intestines, and milk) blood and lymph; localized protection on mucosal surfaces; prevents attachment of microbes to mucosal surfaces; does not activate the complement fixation

Question 19

IgD

Answer 19

monomer; located in the B cell surface, blood and lymph, serum function not know but the presence on B cells functions in initiation response; does not activate the compliment fixation

Question 20

IgE

Answer 20

monomer; located bound to mast and basophil cells through out the body, and in the blood, functions in allergic reactions; possibly lysis of parasitic worms; does not activate the complement system

Question 21

T dependent antigen

Answer 21

an antigen that will stimulate the formation of antibodies only with the assistance of T helper cells

Question 22

MHC ( major histocompatibility complex

Answer 22

the genes that code for histocompatibility antigens

Question 23

plasma cells

Answer 23

a cell that an activated B cell differentiates into; plasma cells manufacture specific antibodies

Question 24

memory cell

Answer 24

a long-lived B or T cell responsible for the memory or secondary response

Question 25

clonal selection

Answer 25

the development of clones of B and T cells against a specific antigen

Question 26

class switching

Answer 26

ability of a B cell and to produce a different class of antibody against a specific antigen

Question 27

clonal deletion

Answer 27

the elimination of B and T cells that react with self

Question 28

T independent antigen

Answer 28

an antigen that will stimulate the formation of antibodies without the assistance of T helper cells

Question 29

antigen-antibody complex

Answer 29

the combination of an antigen with the antibody that is specific for it;the basis of immune protection and many diagnostic tests

Question 30

affinity

Answer 30

the bond between antigen and antibody

Question 31

agglutination

Answer 31

a joining together or clumping of cells

Question 32

opsonization

Answer 32

the enhancement of phagocytosis by coating microorganisms with certain serum proteins;

Question 33

antibody dependent cell mediated cytotoxicity

Answer 33

killing of antibody coated cells by natural killer cells and leukocytes

Question 34

neutralization

Answer 34

an antigen-antibody reaction that inactivates a bacterial exotoxin or virus

Question 35

complement fixation

Answer 35

the process in which which the complement combines with the antigen-antibody complex