想

2580DIAMONDETAL.J.VIROL.

A

(nineFIG.harvestedleft1.panels)(A)WNVandantigen expressioninthebrainsofwild-typewith8or9daysafterMTinfection(threewithrightWNV,panels)mice.Brainswereratrebralserum.ratanti-WNVTypicalsectionspolyclonalserumoracontrolsectioned,negativeandpolyclonalstainedpendentcortexareshownandfromarerepresentativethecerebellum,ofbrainmorestem,andce-infection,brainsfromeitherwild-typeor MTmice.Atthanday108inde-after nohistochemistry.MTmiceapproximatelyhadbrainsthat40%stainedofthepositivewild-typeformiceviralantigenand100%byimmu-ofthestainedrons.darkbrown.Afterdevelopmentwithsubstrate,viralantigenheavilyIninfectiousinfectedthebrainneuronsstemArrowsandindicatecancortexbeseen.ofexamples(B) MTofheavilyinfectedneu-Scattermice,plotpyknoticofthenucleiof WNVinthebrainsofwild-typeand MTmice.Brainslevelsofofpointvewild-typeassaywereharvested,(solidcircles)homogenized,or MT(opensquares)miceateachtimeindicatedinBHK21(bythedottedcells.Theline.limitViraloflevelssensitivityandsubjectedatdayof6(Ptheto plaqueviralplaque0.03)andassayisasP 0.01)werestatisticallydifferentbetweenwild-typeand MTdaymice8brainsofinfectedRAG1mice(datanotshown).Becausetheseofdeterminedmiceweresosusceptibletoinfection,adoptivetransferstudies80%micehadviralbytwo-tailedburdensbelowStudent’sttest.Thefollowingpercentages10wereperformedtode nelymphocytesubsetsthatprotecteddaywildofday6andtype,4day40%wildtype,8 MT.

ofday40%12wildofdaythetype,6levelwildof40%type,detectionofday20%4of( MTday 10and8PFU/g):and0%dayofagainstdisseminatedWNVinfection.Notably,immunesplenocytesorBcellsweresuf cienttoconferprotection(im-munesplenocytes,P 0.006;immuneBcells,P 0.01[Fig. ectedbythefactthat50%oftheanimalsdiedafteradose2C])tosomeRAG1mice.Tocon rmtheimportanceofBcellsof1PFU(50%lethaldose)viafootpadinoculation(datainmediatingprotection,infectionexperimentswereperformednotshown).

withcongenicB-cell-de cientmice.MicethatlackmatureBTounderstandthemechanismbywhichade ciencyinBcells(strain MT)exhibitedasimilarsusceptibilitytoinfec-cellsmademicevulnerabletolethalinfectionbyWNV,infec-tion.Ateitherthehigh(106PFU)orlow(102PFU)dosetiousviruswasmeasuredintissuesbyusingplaqueassays.tested,allanimalssuccumbedtoinfection(P 0.0001)(Fig.Becausetheanalysiswaslimitedbythesmallamountofsam-2D).Thevulnerabilityof MTmicetoinfectionwasre-

pleforsometissues(e.g.,lymphnodes),thelevelof

WNV

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