Medical Microbiology

ImmunologicalMemory............................................

Immunologicalmemoryisusuallydefinedbyanearlierandbetterimmune

response,mediatedbyincreasedfrequenciesofspecificBorTcellsasdeter-

minedbyinvitrooradoptivetransferexperiments.B-cellimmunological

memoryismorecompletelydescribedastheabilitytomediateprotective

immunitybymeansofincreasedantibodyconcentrations.Higherfrequen-

ciesofspecificBandTlymphocytesalone,appearstoonlyprovidelimited

94 2 BasicPrinciplesofImmunology

Table2. 7 BCellsDoNotDifferentiatebetweenSelfandNonselfAntigens,but

RatherDistinguishRepetitive(UsuallyNonself)fromMonomeric

(UsuallySelf)Antigens

Antigen Bcells

present

IgMresponse

Tcell-

indepen-

dent

Thelp

present

Tcell-

depen-

dent

Oncell

membranes

inthebone

marrow

Highcon-

centration

Self Unclear

• 
  
  
  
  • – –
  
  
  
  

Lowcon-

centration

Self +^1 +^1 – +^1

Monomeric

antigen

Highcon-

centration

Self +^1 notap-

plicable

• –

Lowcon-

centration

Non-

self

+ notap-

plicable

+ +

Repetitive,

identical 5 –

10 nm

intervals,para-

crystalline

Self

(very

rare)^2

+ (+)^2 (+) (+)

Nonself

(“always”

infectious)

+ + + ++

(^1) Bcellsarepresentandarestimulatedbyantigenarrangedinarepetitiveand
paracrystallinepattern(Thelper-independenttypeI).B-cellresponsestopoorlyor-
ganizedormonomericantigensarenotdirectlyinduced;insuchcases,indirect
(Thelper-independenttypeII)orconventionallycoupledThelpisrequired.
(^2) SuchselfantigensarenotnormallyaccessibletoBcells;howevercollagenspresents
inlesions,oracetylcholinereceptors,maystimulateandpossiblyactivateBcells.
WhencombinedwithThelp,thisactivationcanresultinanautoimmuneresponse.
2
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Kayser, Medical Microbiology © 2005 Thieme
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