thatareeithervirallyinfectedortu-
morous.
Nudemice:Amousestrainwhichcarriesa
spontaneousmutationresultinginthe
animalshavingnohair,andusually
beingathymic.
NZB/W:Astrainofmousebredasanani-
malmodelforsystemiclupuserythe-
matosus.
Opsonization:Depositionsofproteinson
aninfectiouspathogen,thatfacilitate
phagocytosisofthepathogen(e.g.,
antibodiesandC3b).
Paratope:Thepartofanantibodymole-
culewhichcontactstheantigenicde-
terminant(epitope);theantigen-bind-
ingsite(ABS)ontheantibody.
PC:Phosphorylcholine;acommonlyused
haptenfoundonthesurfaceofanum-
berofmicroorganisms.
PCA:Passivecutaneousanaphylaxis; a
classicdetection reaction for anti-
gen-specificIgE.
PFC:Plaqueformingcell;anantibody-pro-
ducingcellwhichcanbedetectedby
thehemolysisplaquetest.
PHA:Phytohemagglutinin;amitogenforT
cells.
Plasmacell:Anantibody-producingBcell
whichhasreachedtheendofitsdiffer-
entiationpathway.
PMN: Polymorphonuclear neutrophilic
granulocytes.
Pokeweedmitogen:Amitogenfor B
cells.
Polyclonal:Atermdescribingproducts
derivedfromanumberofdifferent
cell clones (e.g.,polyclonalantibo-
dies).
Primarylymphoidtissues:Thymus,bur-
saofFabricius(inbirds),bonemarrow.
Primaryresponse:Theimmuneresponse
whichfollowsaninitialencounterwith
aparticularantigen(seepriming,sec-
ondaryresponse).
Priming:Followinganinitialcontactwith
anantigen,animmunocompetentcell
becomessensitizedor“primed.”
Prozonephenomenon:Lackofameasur-
ableresponseathigh-testsubstance
concentrations.
Pseudoalleles:Tandemvariantsofagene,
whichdonotoccupyahomologous
positiononthechromosome.
Pseudogenes:Genescontainingstruc-
tureswhicharehomologoustoother
genes,butwhichcannotbeexpressed.
RANTES:Regulatedonactivation;thisis
normallyexpressedandsecretedby
Tcells.
Reagin:HistoricaltermforIgE.
Rearrangement:Forinstancetherearran-
gementofgeneticinformationinso-
maticBandTcells.
Recombination:Aprocessbywhichge-
neticinformationisrearrangedduring
meiosis.
Reticuloendothelialsystem(RES):Pha-
gocyticcellsdistributedwithinthe
supportiveconnectivetissueoftheli-
ver,spleen,lymphnodes,andotheror-
gans(e.g.sinusendothelialcells,Kupf-
fercells,histiocytes).
Rhesus(Rh)antigens:Antigenicproteins
presentonthesurfaceoferythrocytes
inapproximately 85 %ofallhumans.
Rheumatoid factor (RF): Autoantibo-
dies—theseareusuallyIgMbutcan
alsobeoftheIgGandIgAisotypes—
whicharespecificallydirectedagainst
thebody’sownIgGmolecules.
SCID: Severe combined immunodefi-
ciencydisease;acongenitaldeficiency
ofthehumoralandcellularimmune
system,resultingfromalackofboth
TandBcells.Theanimalmodelis
theSCIDmouseandisaspontaneous
mutant.
SDF-1alpha:Stromalcell-derivedfactor.
Secretorypiece:AnIgA-associatedpoly-
peptideproducedbyepithelialcells,
andwhichfacilitatesthetransmem-
branetransportofIgA.
Secondaryresponse:Theimmunere-
sponsewhichfollowsaseconden-
counterwithaspecificantigen.
Serumsickness:AninflammatorytypeIII
reaction,occurringafterrepeatedin-
jectionofaforeignprotein.
SLC:Secondarylymphoidorganchemo-
kine.
SLE:Systemiclupuserythematosus.Glossary 1432All rights reserved. Usage subject to terms and conditions of licenseKayser, Medical Microbiology © 2005 Thieme
All rights reserved. Usage subject to terms and conditions of license.