TOP KEY Questions And Answers On HMX

TOP KEY Questions And Answers On
HMX
2csignalcrequirementcofcTccellcactivationc-cCORRECTccANSWER-
costimulationcmakescsurecthatcTccellcactivationchappensconlycwhencthereciscacmicrobecpres
ent.cThecDCcwillcinternalizecmicrobe,cpresentcpeptideconcthecMHCcmolecule.cTccellcwillcbind
candcbiochemcsignalscwillcbecreleasedcthatcarecrequiredcforcactivationc=csignalcnumberc1c(an

tigen)

Signalc2ccomescthecmicrobecPAMPcbindingctocthecTLRconcthecDC.cThisccausesctheccostimu
latorcofcthecDCctocbindctoctheccostimulatorycreceptorcofcthecTccell.c
Mostccommonccostimulator=CD80/CD86c(B7-
1/2).cThecmostccommonccostimcreceptor=cCD28.c
socCD80corcCD86cwillcbindcCD28cofcthecTccellc(signalc2).

affinitycmaturationc-cCORRECTccANSWER-
WhencthecTcfollicularchelperccellscbindctocthecBccellscviacCD40,citccancinducecmutationscincth
ecvariablecregion.cThiscmeanscthatcBccellsccreatedcincthecgerminalccentercwillchavecslightlycd
ifferentcbindingcsites.cthisccancresultcincincreasedcaffinitycforcthecantigen,cdecreased,corcnoce
ffect.

antibodycdepedentccellularccytotoxicityc-cCORRECTccANSWER-
incthiscpathway,cthecviralcparticlecinctheccellcwillcreleasecspikrcproteinscthatcwillcbeclocatedcon
cthecsurfacecofctheccell.cAntibodiescwillcbindctocthecspikecprotein.cThecFccregioncwillcbecrecog

nizedcbycNKccellcthatcwillcreleasecgranulescthatcwillckillctheceffectedccell.

Attackingcself--complementcfixationc-cCORRECTccANSWER-
Incthiscpathway,cRBCscandcepithelialccellschavecselfcreceptors.cIgGcbindsctocthecselfcrecept
orsconcthecRBCscandcIgMcbindsctocthecselfcreceptorsconcthecepithelialccells.cThiscresultscinct
hecrecruitmentcofccomplementcproteinscthatcwillclysectheccellscandckillcthem.cWecdocnotcwant
cthis.




attackingcself--inflammatorycresponsec-cCORRECTccANSWER-
incthiscpathway,citciscaccombinationcofccomplementcandcopsonization.cFirstcancIgcwillcrecogn
izecthecselfcproteinconctheccell.cThiscwillcleadsctoccomplementcfixationcincwichccomplementcp
roteinscarecrecruited.cC3acandcC5acarecthecinflammatoryccomplementcpoteins.cTheycactcsi
milarlyctocTNF-
acandcILcincthatctheycrecruitcleukocytescfromcthecbloodcstreamcleadingctocinflammation.cOnc

, ecthecneutrophilcentercthectissue,citcwillcrecognizecthecFccregioncofcthecantibodyc(opsonizatio
n).cItcwillcattemptctockillctheccell,cbutcsincecitcisclockedcincplace,cthecNKccellcwillcbecunablectocki
llcit=frustratedcphagocytosis.cSocthencneutrophilcreleasesctoxiccgranulescthatcwillckillctheccell
.

attackingcself--neutralizationc-cCORRECTccANSWER-
incneutralization,cIgcpreventscviralcparticlescfromcbindinctocviralcreceptorsconctheccell.cWhenc
thecantibodiescstartcpreventingcselfcmoleculescfromcbindingctocreceptors,cwechavecproblem
s.

attackingcself-opsonizationc-cCORRECTccANSWER-
antibodiescwillcbindctocantigensconcthecRBCscandcthencacmacrophagecwillcbecsignaledctocco
mecandckillctheccell.cWhencourcownccellscareccoatedcwithcantibodiescitcleadsctocphagocytosis
cofcourcownccells.




BccellcTccellccollaborationc-cCORRECTccANSWER-
Acpeptidecwillcbecpresentedconcacclassc2cMHCcfromctheclysosome.cItcwillctravelctoctheclymphc
nodecandcbindcacspecificcTccellcleadingctocproliferation.cItcwilclinducecacchemokinecreceptorct
ocbecproduced--
CXCR5cwhichciscusuallycexpressedconcBccells.cThiscwillccausectheccomplexctocmovectoward
scthecBccellczone.cThecBccellcthencbindscitcandcitcbeginsctocexpresscCCR7cofcTccellscandcitcmo
vesctowardscthecTczone.cBcandcTcnowcmeetcup.cThecBccellchascCD40concthecsurfacecandcthe
cTccellschavecCD40LcwhichcbindscCD40ccausingcBccellcproliferation.cBccellscexpandcandcma

kecshortclivedcplasmaccellscthatcsecretecantibodies.c

(ThecCD4ccellcwillcbecpresentedcthecfragmentedcviralcparticlecfromcthecBccellcandcitcwillcbindc
throughcthecCD40Lcreceptor).

BccellscVscTccellsc-cCORRECTccANSWER-
Bccellscarecablectocseeceverything.cTheycseecviralcparticles,cfragments,cpieces,cetc.cSoctheyc
cancwastectimecbindingctocfragmentedcpiecescthatcarecnotcharmfulcwhenctheyccouldcbecbindi
ngctocfunctioningcviralcparticlescthatcarecstillcablectocinfiltratectheccell.cTccellsconcthecothercha
ndcarecblindcandcrequirecMHCcpresentingccellsctocseecthecviralcparticles.cItccancignorecthecvi
ralccloudctocgetctocthecviralcparticlescthatcarecthecmostcharmful.

clonalcexpansionc-cCORRECTccANSWER-
Thecstepcaftercclonalcselectionciscclonalcexpansion.cThiscwillcresultcincthecproductioncofc10sc
ofc1000scofclymphocytescthatcarecspecificcforcthatcintialcmicrobe.

clonalcselectionc-cCORRECTccANSWER-
whencacpathogenciscfirstcpresentedcinctheccell,ctherecarecnotcBcandcTccellscincabundancectha
tcwillcrecognizecthecpathogen.cAtcfirst,cmaybeconecorctwoclymphocytescwillcrecognizecthecpat
hogen--thisciscclonalcselection.