title: Monoclonal Antibodies Against the Staphylococcus aureus Bicomponent Leukotoxin AB Isolated Following Invasive Human Infection Reveal Diverse Binding and Modes of Action.
abstract: The 2-component leukotoxin LukAB is critical for Staphylococcus aureus targeting and killing of human neutrophils ex vivo and is produced in the setting of human infection. We report 3 LukAB-specific human monoclonal antibodies (mAbs) with distinct mechanisms of toxin neutralization and in vivo efficacy. Three hybridomas secreting mAbs with anti-LukAB activity (designated SA-13, -15, and -17) were generated from B cells obtained from a 12-year-old boy with S. aureus osteomyelitis. Each of the 3 mAbs neutralized LukAB-mediated neutrophil toxicity, exhibited differing levels of potency, recognized different antigenic sites on the toxin, and displayed at least 2 distinct mechanisms for cytotoxic inhibition. SA-15 bound exclusively to the dimeric form of the toxin, suggesting that human B cells recognize epitopes on the dimerized form of LukAB during natural infection. Both SA-13 and SA-17 bound the LukA monomer and the LukAB dimer. Although all 3 mAbs potently neutralized cytotoxicity, only SA-15 and SA-17 significantly inhibited toxin association with the cell surface. Treatment with a 1:1 mixture of mAbs SA-15 and SA-17 resulted in significantly lower bacterial colony counts in heart, liver, and kidneys in a murine model of S. aureus sepsis. These data describe the isolation of diverse and efficacious antitoxin mAbs.
authors.affiliation: Department of Pediatrics.
authors.forename: Isaac P
authors.initials: IP
authors.lastname: Thomsen
authors.affiliation: Department of Pediatrics.|Vanderbilt Vaccine Center, and.
authors.forename: Gopal
authors.initials: G
authors.lastname: Sapparapu
authors.affiliation: Department of Microbiology, New York University School of Medicine, New York, New York.
authors.forename: David B A
authors.initials: DBA
authors.lastname: James
authors.affiliation: Department of Pediatrics.|Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee ; and.
authors.forename: James E
authors.initials: JE
authors.lastname: Cassat
authors.affiliation: Department of Pediatrics.
authors.forename: Meera
authors.initials: M
authors.lastname: Nagarsheth
authors.affiliation: Vanderbilt Vaccine Center, and.
authors.forename: Nurgun
authors.initials: N
authors.lastname: Kose
authors.affiliation: Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee; and.
authors.forename: Nicole
authors.initials: N
authors.lastname: Putnam
authors.affiliation: Department of Microbiology, New York University School of Medicine, New York, New York.
authors.forename: Kristina M
authors.initials: KM
authors.lastname: Boguslawski
authors.affiliation: Department of Pediatrics.
authors.forename: Lauren S
authors.initials: LS
authors.lastname: Jones
authors.affiliation: Department of Pediatrics.
authors.forename: James B
authors.initials: JB
authors.lastname: Wood
authors.affiliation: Department of Pediatrics.
authors.forename: Clarence B
authors.initials: CB
authors.lastname: Creech
authors.affiliation: Department of Microbiology, New York University School of Medicine, New York, New York.
authors.forename: Victor J
authors.initials: VJ
authors.lastname: Torres
authors.affiliation: Department of Pediatrics.|Vanderbilt Vaccine Center, and.|Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee ; and.
authors.forename: James E
authors.initials: JE
authors.lastname: Crowe
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D000911:Antibodies, Monoclonal / Q000097:blood*; D001402:B-Lymphocytes / Q000276:immunology; D001426:Bacterial Proteins / Q000276:immunology*; D002648:Child; D005260:Female; D006801:Humans; D006825:Hybridomas; D007956:Leukocidins / Q000276:immunology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009504:Neutrophils / Q000276:immunology*; D012044:Regression Analysis; D013203:Staphylococcal Infections / Q000382:microbiology*; D013211:Staphylococcus aureus
chemical_list: D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins; D007956:Leukocidins; C586430:leukocidin AB, Staphylococcus aureus
keywords: LukAB; Staphylococcus aureus; hybridoma; leukocidin; monoclonal; toxins.