1-Antibodies

Question 1

features of adaptive immunity

Answer 1

1. specificity
2. immunologic memory
3. diversity
4. self regulation
5. discrimination

Question 2

specificity

Answer 2

adaptive immune response generated towards determinants/epitopes

bc lymphocytes have cell membrane receptors for one specificity

Question 3

immunologic memory

Answer 3

memory cells make faster and more vigorous resp upon re-exposure to antigen

memory cells more sensitive to stim by antigen than antigen-naive lymphocyte

Question 4

diversity

Answer 4

pre-existing antigen specific lymphocyte react with 1x10^9 (a ton) of antigens

expression of cell surface receptors that can react with diverse number of antigens

Question 5

self regulation

Answer 5

regulation via
1. removal of antigen so no immunologic stimulation
2. activated lymphocytes die w/i short period by apoptosis
3. regulatory immune mechanism

Question 6

discrimination of self vs non

Answer 6

adaptive immune resp directed normally vs foreign antigens NOT self antigens

immune cells that are specific for self are destroyed/regulated

lead to autoimmune disease occur if lost

Question 7

immunogenicity

Answer 7

properties of an antigen that promote an immune response

big immune resp = high immunogenicity
ex. bacteria/fungi high bc so foreign

Question 8

adjuvant

Answer 8

immunogenicity is inc
prolonged retention of an antigen so time for more vigorous immune resp can occur

ex. alum, mineral oil, lipids

Question 9

antigenicity

Answer 9

properties that allow a substance to react with an antibody

Question 10

haptens

Answer 10

small molecules that cannot induce antibody formation BUT can react with antibody that is specific for it aka hapten = antigen NOT immunogen

-must be coupled to a carrier molecule to induce antibodies

Question 11

features of immunogens

Answer 11

1. size - bigger size = better immunogen
2. internal complexity- more complex = more immunogenic, proteins good
3. degradability- immunogen processing must occur, proteins > peptides
4. foreigness- tolerance to self antigens so must be foreign
5. accessibility- easy to reach areas more likely induce immune response aka immunodominant areas

Question 12

antigen conformation

types of determinants

Answer 12

conformational determinants- amino acid residues must be in 3D structure to bind antibody, if denatured not work

linear determinants- adjacent aminos will bind antibody when denatured, not accessible if native strucutre

neoantigens- new antigens formed by proteolysis to make new determinant

T lymphs only recog linear determinants

Question 13

types of antigens

Answer 13

most common are proteins and most immunogenic
-from serum proteins or microbes

also lipoproteins (cell membranes), polysaccs (bacterial capsules), glycoprotein (blood), polypeps (hormones), nucleic acids (cells, microbes)

Question 14

antibodies/immunoglobulins

general

Answer 14

-present in body humors/fluids
-effects mediated by glycoproteins binding to antigen specifically
-will not be present until stimulated/exposed by antigen
‘gamma globulin’ also used

Question 15

antibody locations

Answer 15

-surface of B lymphocytes antigen receptors specific to one, if naive-B then have both IgM and IgD
-blood plasma and tissue fluids
-surface of mast cells/basophils IgE
-secretory fluids (mucus and milk)

Question 16

antiserum

Answer 16

antibody containing serum
-fluid portion of blood after cellular parts clotted

either polyclonal (pop of antis that bind 1+ antigens) OR monoclonal (antibody bind only 1)

Question 17

antibody titer

Answer 17

reciprocal of the LAST dilution of antiserum that still yields a demonstrable antibody binding reaction

aka take the last reaction and inverse it

Question 18

antibody strucutre

Answer 18

2 heavy chains + 2 light chains

heavy are connected to each other and to light chains by disulfide bonds

constant and variable regions
-variable is what forms antigen bind site

Question 19

subdivisions of variable region

Answer 19

1. hypervariable- binding surface, varying amino acids here make antigen specificity
2. framework- support hypervariable

Question 20

antibody properties

structural, isotypes

Answer 20

-IgA/D/G have hinge region for flexibility
-two isotypes= secretion or membrane form, D has membrane only
-secretory form of M and A have j chains for pentamer/dimer/trimer formation
-isotype switching allow single antigen specificity for diff functions

M is pentamer, A dimer or trimer

Question 21

proteolysis of antibodies

Answer 21

either produce two Fab fragments each w/ binding site + 1 Fc frag (split in 3) Papain OR

single Fab with 2 binding sites + no surviving Fc frag (split once + itty bitty frags) Pepsin

Question 22

antibody classification

Answer 22

based on diffs in amino seq of heavy chains
IgA/D/E/G/M

IgG has subisotypes 1-4
IgA has 1-2

Question 23

antibody monomers

Answer 23

IgG
IgE
IgD

Question 24

polymer antibodies

Answer 24

IgM
IgA

Question 25

IgG

Answer 25

-most abundant immunoglobulin in normal serum -secretory form is monomer -activates complement classical pathway -IgG1 and 3 can opsonize -coat tumor cells or virus infected for ADCC -cross placenta for immunity to fetus -in mother's milk so taken up by infant gut lumen and transported into blood

Question 26

IgM

Answer 26

-secretory form is pentamer -excellent complement activator better than G -predominate antibody in primary immune resp

Question 27

IgA

Answer 27

-mediator of mucosal immunity -@ tears, saliva, colostrum, milk -monomeric in serum, dimer in secretory held by j chain -eosinophil mediated ADCC of parasitic infections

Question 28

mucosal immunity mechanism

Answer 28

IgA gets transported thru mucosal cells by coupled to secretory piece to protect it from proteolytic enzymes and glue it to mucus secretory piece from epithelial cell Fc receptor

Question 29

IgE

Answer 29

-secreted as monomer -eosinophil mediated ADCC of certain parasites -binds to cell surface receptors for IgE on basophils and mast cells to mediate allergies and anaphylaxis

Question 30

IgD

Answer 30

-very low in serum but primarily @ surface of antigen naive B lymphs with IgM -important for transduction of signals across plasma membrane for antigen driven B cell activation

Question 31

affinity | definition

Answer 31

strength of binding for antigen of 1 antigen combining site for a pop of antibodies affinity will inc with repeated immunization with an antigen

Question 32

avidity

Answer 32

overall strength of attachment based on how many combining sites the antibody has bound

Question 33

allotype

Answer 33

differences in constant regions of antibodies but same isotype bc of multiple alleles

Question 34

idiotype

Answer 34

collection of hypervariable regions by heavy and light chains that form antigen binding site