title: Five birds, one stone: neutralization of α-hemolysin and 4 bi-component leukocidins of Staphylococcus aureus with a single human monoclonal antibody.
abstract: Staphylococcus aureus is a major human pathogen associated with high mortality. The emergence of antibiotic resistance and the inability of antibiotics to counteract bacterial cytotoxins involved in the pathogenesis of S. aureus call for novel therapeutic approaches, such as passive immunization with monoclonal antibodies (mAbs). The complexity of staphylococcal pathogenesis and past failures with single mAb products represent considerable barriers for antibody-based therapeutics. Over the past few years, efforts have focused on neutralizing α-hemolysin. Recent findings suggest that the concerted actions of several cytotoxins, including the bi-component leukocidins play important roles in staphylococcal pathogenesis. Therefore, we aimed to isolate mAbs that bind to multiple cytolysins by employing high diversity human IgG1 libraries presented on the surface of yeast cells. Here we describe cross-reactive antibodies with picomolar affinity for α-hemolysin and 4 different bi-component leukocidins that share only ∼26% overall amino acid sequence identity. The molecular basis of cross-reactivity is the recognition of a conformational epitope shared by α-hemolysin and F-components of gamma-hemolysin (HlgAB and HlgCB), LukED and LukSF (Panton-Valentine Leukocidin). The amino acids predicted to form the epitope are conserved and known to be important for cytotoxic activity. We found that a single cross-reactive antibody prevented lysis of human phagocytes, epithelial and red blood cells induced by α-hemolysin and leukocidins in vitro, and therefore had superior effectiveness compared to α-hemolysin specific antibodies to protect from the combined cytolytic effect of secreted S. aureus toxins. Such mAb afforded high levels of protection in murine models of pneumonia and sepsis.
authors.affiliation: a Arsanis Biosciences ; Vienna , Austria.
authors.forename: Harald
authors.initials: H
authors.lastname: Rouha
authors.forename: Adriana
authors.initials: A
authors.lastname: Badarau
authors.forename: Zehra C
authors.initials: ZC
authors.lastname: Visram
authors.forename: Michael B
authors.initials: MB
authors.lastname: Battles
authors.forename: Bianka
authors.initials: B
authors.lastname: Prinz
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Magyarics
authors.forename: Gábor
authors.initials: G
authors.lastname: Nagy
authors.forename: Irina
authors.initials: I
authors.lastname: Mirkina
authors.forename: Lukas
authors.initials: L
authors.lastname: Stulik
authors.forename: Manuel
authors.initials: M
authors.lastname: Zerbs
authors.forename: Michaela
authors.initials: M
authors.lastname: Jägerhofer
authors.forename: Barbara
authors.initials: B
authors.lastname: Maierhofer
authors.forename: Astrid
authors.initials: A
authors.lastname: Teubenbacher
authors.forename: Ivana
authors.initials: I
authors.lastname: Dolezilkova
authors.forename: Karin
authors.initials: K
authors.lastname: Gross
authors.forename: Srijib
authors.initials: S
authors.lastname: Banerjee
authors.forename: Gerhild
authors.initials: G
authors.lastname: Zauner
authors.forename: Stefan
authors.initials: S
authors.lastname: Malafa
authors.forename: Jakub
authors.initials: J
authors.lastname: Zmajkovic
authors.forename: Sabine
authors.initials: S
authors.lastname: Maier
authors.forename: Robert
authors.initials: R
authors.lastname: Mabry
authors.forename: Eric
authors.initials: E
authors.lastname: Krauland
authors.forename: K Dane
authors.initials: KD
authors.lastname: Wittrup
authors.forename: Tillman U
authors.initials: TU
authors.lastname: Gerngross
authors.forename: Eszter
authors.initials: E
authors.lastname: Nagy
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000737:chemistry / Q000276:immunology*; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology*; D000918:Antibody Specificity; D001426:Bacterial Proteins / Q000737:chemistry / Q000276:immunology*; D002460:Cell Line; D006460:Hemolysin Proteins / Q000737:chemistry / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry / Q000276:immunology*; D007956:Leukocidins / Q000737:chemistry / Q000276:immunology*; D011817:Rabbits; D013211:Staphylococcus aureus / Q000737:chemistry / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins; D006460:Hemolysin Proteins; D007074:Immunoglobulin G; D007956:Leukocidins
keywords: BLI, biolayer interferometry; EC50, effective concentration; Hla, α-hemolysin; HlgAB and HlgCB, gamma-hemolysins; IC50, inhibitory concentration; LukED, leukocidin ED; LukSF, leukocidin SF; PMN, polymorphonuclear cells; RBC, red blood cell; Staphylococcus aureus; engineered cross-reactivity; exotoxins; in vitro potency; in vivo efficacy; mAb, monoclonal antibody; monoclonal antibody; toxin neutralization