title: Human microvascular endothelial cell toxicity caused by Brazilian purpuric fever-associated strains of Haemophilus influenzae biogroup aegyptius.
abstract: An in vitro cytotoxicity model that uses an immortalized human microvascular endothelial cell line (HMEC-1) differentiates Brazilian purpuric fever (BPF)-associated Haemophilus influenzae biogroup aegyptius (HAE) strains from non-BPF-associated HAE strains. Toxic strains produced a characteristic HMEC-1 phenotype at an MOI of < 1 bacterium/1000 tissue culture cells (TCC). Nontoxic strains required MOIs of > 1000 bacteria/TCC to produce an observable effect. The cytotoxic phenotype was characterized by the presence of large clumps of HMEC-1 cells, which detached from the monolayer within 48 h of inoculation by HAE cells. The cytotoxic phenotype was observed with 100% of BPF-associated HAE (40/40) and 14% of non-BPF-associated HAE (8/57; P < .001). The ability to study a BPF-associated phenotype in vitro using human microvascular cells should enhance our knowledge of BPF pathogenesis.
authors.affiliation: Emerging Bacterial and Mycotic Disease Branch, Centers for Disease Control and Prevention, Atlanta, Georgia 30333.
authors.forename: R S
authors.initials: RS
authors.lastname: Weyant
authors.forename: F D
authors.initials: FD
authors.lastname: Quinn
authors.forename: E A
authors.initials: EA
authors.lastname: Utt
authors.forename: M
authors.initials: M
authors.lastname: Worley
authors.forename: V G
authors.initials: VG
authors.lastname: George
authors.forename: F J
authors.initials: FJ
authors.lastname: Candal
authors.forename: E W
authors.initials: EW
authors.lastname: Ades
mesh_terms: D002460:Cell Line; D004730:Endothelium, Vascular / Q000382:microbiology*; D006192:Haemophilus Infections / Q000473:pathology*; D006193:Haemophilus influenzae / Q000472:pathogenicity*; D006801:Humans; D066298:In Vitro Techniques