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Where are most abs found?

the thrid fastest migrating group of globulins, named gamma globulins for the thrid letter of the Greek alphabet (count alpha 1 and alpha 2 as one)

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antibodies functions

immunomodulation reduced damage to host from inflammatory response organized T cell response opsonization activation of complement toxin neutralization direct antibacterail acitvity

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Abs have a basic unit of?

four polypetide chains

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What are the chains of abs?

two light chains and heavy chains, bound together by covalent disulfide bridges as ewll as by noncovalent interactions

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What can abs be proteolytically cleaved to yield?

Fab fragments(fragment Ag binding Fab) and an Fc fragment (fragment crystallized, Fc) responsible for effector functions

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What are both H and L chains dividied into?

V and C regions

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the V region

containg the Ag binding site

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C region

determining the fate of the Ag

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What are the five different kinds of H chains?

epsilon, alpha, gamma, u, ga...

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What do the H chains determine?

the class of antibody.... M, D, E, A

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What are the two different kinds of L chains?

k and lambda, each with a MW of 23kDa

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Each Ab unit can have only k and lambda

L chain, but not both

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What do both H and L chains have?

intrachain disulfide bridges every 90 amino acid residues, which creates polypetpteide loops, domains, of 110 amino acids

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What are the domains refered to?

Vh, Vl, Ch1, Ch2, etc

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Know what parts are responseibl efor

on basic structure of Abs

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Abs have lots of flexibility, bc?

hinges

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What is the Ag binding sites formed by? Secreted IgG

the juxtaposition of Vl and Vh domains

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Where does the heavy chain C regions end? Secreted IgG

tail pieces

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Whaat is the location of complement and Fc receptor biding sites/ Secreted IgG

within the heaby chain constant regions are approximations

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membrane-bound IgM on B cell... has ...... thant IgG

one more Ch domain

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membrane bound IgM on B cells

has C terminal trnasmembran and cytoplamsic protions that anchor the molecule in the plasma membrane

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Igm is for?

activation of phagocytosis

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What is IgG cleaved by?

The enzymes papain at the hinges

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What does papain diegestion in IgG allow?

the separation of two Fab fargments and complemetn and Fc receptors biding the Fc fragment

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what generates a single bivalent antigen bidning fragment F(ab')2...

pesin..... makes fragments of IgG

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What are the two roles of hinges?

widely spaced cell surface determeinatn closely spaced cell sufrace determinatns

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What is teh flexibiilty due to..

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What are a large group of cell sufrace and solubel proteins involved in?

Recognition, binding, or adhesion process of cells belogs to the imunoglobulin super family

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What are Ig superfamily proteins? list 6

IgG, TCR, Class I MHC, CD4, CD28, ICAM1

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Ig ag binding site

three CDrs in Vh and three CDRs in Vl domains

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T cell receptor Ag binding site

three CDRs in Valpha and three CDRs in Vbeta domains

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Ig Ag that may be bound

proteins, lipids, polyscaccarides and small chemicals

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T cell receptors Ag that may be bound

peptide MHC complexes

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Ig antigenic determinatns recognized

linear and conformational determinats of various macromolecules and chemicals

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T cell receptor antigenic determinants recognized

linear determinants; only 2 or 3 aa residues of a petide boudn to an MHC molecule

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Ig affinity of Ag binindg

Kd 10^-7-10^-11 M

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Ig on-rate/ off rate

rapid on rate, variable off rate

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T cell recetor affinity of Ag binding

Kd 10^-5-10^-7M

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Ig Onrate/off rate

slow on rate slow off rate

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CDR

complementarity determining region

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Kd

disociation constant

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Vh

variable domain of heavy chaing Ig

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Vl

vairable domain of light chain ig

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from the H and L chain are loops that protrude from the surface of the two Ig V domains and in combination creat an Ag binding region

complementarity- determining regions (CDRs)

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What is each domain of the Ag binding site composed of?

two anitparallel beta strands, colored yellow and red, to form two beta pleated sheets held together by a disulfide bond

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Confamitonal determinatn---> denaturation

determinant lost by denaturation

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linear determinant nenaturation of

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neoantigenic determinant (created by proteolysis)

determinatnnear site of proteolysis

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the tighness of Ag-Ab binding

affinity

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Abs ??? in their affinity to the same Ag determinant

vary

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The higher the..... the less liekly the Ab is to ...... from the Ag

binding contstnt, dissociate

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Abs formed in the primary response?

soon after the injection of an Ag are gnereally of lower affinity

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Abs produced by memory response?

have higher affinity thatn those in a primary repsosne ( association constats 1000 times higher)

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What is critical in Ab when the Ag is a toxin or virus and must be neutralized rapidly?

affinity

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What is the maximum numnber of antigenic determinatns with which an Ab will react?

the valence of an Ab

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What contains two Fab regions and can bind two moleucles of Ag or two identical sites on the same particles and thus of have valance of???

IgG, two

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What is the valence improtnat for?

binding affinity, as having two or more binding sites for an Ag can dramatically increase the tighness of binding of the Ab to Ags

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What is avidity?

comvined effect that results from synergy of the binding strngths of each binding site

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Stem cell

no Ig expression

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Pre B cell

Cytoplasmic u heavy chaing and pre B receptor

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immature B cell

membrane IgM

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mature B cell

membran IgM, IgD

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Activated B cell

low rate Ig secretion; heavy chain isotype swithcing; affinity maturation

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antibody secreteing cell

high rate Ig secretion; reduced membrane Ig

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most common Ab in mucosal secretions

IgA

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mainly found in the plama

Igm

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absorbed on the surface of mast cells

IgE

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penetrates deeper into the tissue

IgG

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Different microbes have different/

biological properties

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Microbes can enter the body through ?

different routes skin, gi, respiratory tract, genitourinary

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The five different Ab classes such as IgM, IgD, IgG, IgE, and IgA, and their subclasses have evolved

to facilitate protection agianist microbes entering at the different sites

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What classes have a J chain?

A and M

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all Ig have

heavy chain and light chain

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what have seretory ocmpononet?

IgA

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What is the most abudnant immunoglobulin in the blood?

IgG

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What is the IgG class MW?

150 kDa

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Where are IgG found

both in vacular and extravascular spaces as well as in secretion

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What provides the bulk of immunity to most blood borne pathogens?

IgG

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What is the only Ig to cross the placenta?

IgG, it provides

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What is present in the placenta?

The epithelial cell surface receptor for Fc regions (FCRn) of maternal IgG

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What does FCRn do? .

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What is teh major Ig present in extermal secreitons such as colostrum, milk, and saliva?

IgA where it exists as a 420 kDa dimer

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What does the IgA contian?

lambda chian, H alpha chain, two more polypeptide chians secretory component J chaing... joining chain

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What is part of the poly Ig receptor involbed in transepithelial transport of eoxcirn

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