Characterization of Lymphocyte Subsets in the Bronchiolar Lymph Nodes of BALB/c Mice Infected with Cilia-Associated Respiratory Bacillus

摘要

Cilia-associatedrespiratory(CAR)bacillusisanunclassified,gram-negative,extracellularbacteriumthatcauseschronicrespiratorytractdiseaseinrodents.Infectedmicedevelopmicroscopiclesionscharacterizedbyaprimarylymphocyticresponsefollowedbymacrophageandneutrophilicinfiltration.TocharacterizethelymphocyticsubsetsthatrespondtoCARbacillusinfection,BALB/cmicewereinoculatedwith105CARbacillusbacteria.Atsevenweeksafterinoculation,micewereeuthanizedandthetracheobronchiolarandhilarlymphnodeswerecollectedandstainedforcellsurfacemarkerstoTcells(CD3,CD4,andCD8),Bcells(B220,CD5),naturalkiller(NK)cells(pan-NK)andintracellularinterleukin10(IL-10)andinterferon-#59138;(IFN-#59138;).FlowcytometricanalysisoflymphnodesfromCARbacillus-infectedmicerevealed11%increaseinfrequencyofBcells(B220+),12%increaseinthefrequencyofdouble-negative(CD4#8722;CD8#8722;CD3+)Tcells,andslightincreaseintheB-1subsetofBcells(B220+CD5+).TherewasnochangeinthefrequencyofNKcells.TheCARbacillus-infectedmicehadanoveralldecreaseinthefrequencyofTcells.IntracellularcytokinestainingrevealeddistinctpopulationsofTcellsproducingIL-10andIFN-#59138;,andIL-10productionfromBcells;NKcellswerenotasubstantialsourceofIFN-#59138;.Toourknowledge,thisisthefirstcharacterizationoflymphocyticresponsesandsuggestionthatBcellsanddouble-negativeTcellsmaybeprincipallyresponsibleforthelesionsassociatedwithCARbacillusinfection.