Association of cholera toxin with Vibrio cholerae outer membrane vesicles which are internalized by human intestinal epithelial cells

摘要

Choleratoxin(CT)isthemajorvirulencefactorofpathogenicVibriocholerae.ThepresentstudydemonstratesthatafractionofCTisassociatedwiththeoutermembranevesicles(OMVs)releasedbyV.cholerae.Atomicforcemicroscopy(AFM)andalsotransmissionelectronmicroscopy(TEM)ofpurifiedOMVsfromtoxigenicV.choleraeO395revealedsphericalshapedvesiclesofsizerange20–200nm.ImmunoblottingofpurifiedOMVswithpolyclonalanti‐CTantibodyandGM1‐gangliosidedependentELISAsuggestthatCTisassociatedwithOMVs.CHOcellassayindicatedthatOMVassociatedCTisphysiologicallyactive.OMVslabeledwithfluorescentdyeinteractedwithintestinalepithelialcellsviatheCT‐receptorandwereinternalizedincreasingthecAMPlevel.ThusOMVsmayrepresentanimportantvehicleindeliveringCTtoepithelialcells...