Outer membrane derived vesicles (MVs) secreted by @entity3841 @entity39300 contain a membranolytic leukotoxin and are toxic to @entity1 HL60 cells. To determine how MVs interact with @entity1 target cells, HL60 cells were incubated with vesicles, reacted with anti-vesicle antibodies and a @entity2823 -labelled reporter, and visualized by confocal scanning laser microscopy. Target cells rapidly became reactive with anti-vesicle antibodies upon exposure to vesicles. Confocal microscopy showed that labelling occurred primarily in the cytoplasmic membrane and that very little internal fluorescence was observed. The cytoplasmic membrane of HL60 cells was also strongly labelled after exposure to MVs that contained the fluorescent phospholipid, SP-DiOC18. In contrast, incubation of cells with free SP-DiOC18 resulted primarily in the labelling of internal structures of HL60 cells. These results suggest that A. actinomycetemcomitans MVs associate with, or are incorporated into the cytoplasmic membrane of HL60 cells. The leukotoxin is a membranolytic cytotoxin and cells exposed to MVs were lysed by vesicle-associated toxin in a time and dose-dependent manner. However, cells became reactive with anti-vesicle antibodies when MVs were added in the presence of inhibitors of leukotoxin-mediated lysis or when sublytic doses of MVs were analysed. In addition, MVs produced by an isogenic leukotoxin-deficient strain of A. actinomycetemcomitans @entity39300 were non-toxic but rapidly interacted with HL60 cells. These results suggest that A. actinomycetemcomitans MVs can deliver leukotoxin to HL60 cells but that the association of vesicles with the cytoplasmic membrane occurs independently of the leukotoxin polypeptide.

Interaction of XXXX outer membrane vesicles with HL60 cells does not require leukotoxin.

@entity1 :: ('9606', 'Species') :: ['human'] @entity2823 :: ('MESH:D016650', 'Chemical') :: ['FITC'] @entity3841 :: ('714', 'Species') :: ['Actinobacillus actinomycetemcomitans'] @entity39300 :: ('6972', 'Gene') :: ['JP2']
@entity3841 :: (714,Species) :: ['Actinobacillus actinomycetemcomitans']
