title: Structurally designed attenuated subunit vaccines for S. aureus LukS-PV and LukF-PV confer protection in a mouse bacteremia model.
abstract: Previous efforts towards S. aureus vaccine development have largely focused on cell surface antigens to induce opsonophagocytic killing aimed at providing sterile immunity, a concept successfully applied to other Gram-positive pathogens such as Streptococcus pneumoniae. However, these approaches have largely failed, possibly in part due to the remarkable diversity of the staphylococcal virulence factors such as secreted immunosuppressive and tissue destructive toxins. S. aureus produces several pore-forming toxins including the single subunit alpha hemolysin as well as bicomponent leukotoxins such as Panton-Valentine leukocidin (PVL), gamma hemolysins (Hlg), and LukED. Here we report the generation of highly attenuated mutants of PVL subunits LukS-PV and LukF-PV that were rationally designed, based on an octameric structural model of the toxin, to be deficient in oligomerization. The attenuated subunit vaccines were highly immunogenic and showed significant protection in a mouse model of S. aureus USA300 sepsis. Protection against sepsis was also demonstrated by passive transfer of rabbit immunoglobulin raised against LukS-PV. Antibodies to LukS-PV inhibited the homologous oligomerization of LukS-PV with LukF-PV as well heterologous oligomerization with HlgB. Importantly, immune sera from mice vaccinated with the LukS mutant not only inhibited the PMN lytic activity produced by the PVL-positive USA300 but also blocked PMN lysis induced by supernatants of PVL-negative strains suggesting a broad protective activity towards other bicomponent toxins. These findings strongly support the novel concept of an anti-virulence, toxin-based vaccine intended for prevention of clinical S. aureus invasive disease, rather than achieving sterile immunity. Such a multivalent vaccine may include attenuated leukotoxins, alpha hemolysin, and superantigens.
authors.affiliation: Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America.
authors.forename: Hatice
authors.initials: H
authors.lastname: Karauzum
authors.forename: Rajan P
authors.initials: RP
authors.lastname: Adhikari
authors.forename: Jawad
authors.initials: J
authors.lastname: Sarwar
authors.forename: V Sathya
authors.initials: VS
authors.lastname: Devi
authors.forename: Laura
authors.initials: L
authors.lastname: Abaandou
authors.forename: Christian
authors.initials: C
authors.lastname: Haudenschild
authors.forename: Mahta
authors.initials: M
authors.lastname: Mahmoudieh
authors.forename: Atefeh R
authors.initials: AR
authors.lastname: Boroun
authors.forename: Hong
authors.initials: H
authors.lastname: Vu
authors.forename: Tam
authors.initials: T
authors.lastname: Nguyen
authors.forename: Kelly L
authors.initials: KL
authors.lastname: Warfield
authors.forename: Sergey
authors.initials: S
authors.lastname: Shulenin
authors.forename: M Javad
authors.initials: MJ
authors.lastname: Aman
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000596:Amino Acids; D000818:Animals; D057134:Antibodies, Neutralizing / Q000494:pharmacology; D016470:Bacteremia / Q000276:immunology* / Q000382:microbiology / Q000517:prevention & control*; D058491:Bacterial Load / Q000187:drug effects; D001426:Bacterial Proteins / Q000737:chemistry / Q000276:immunology*; D001427:Bacterial Toxins / Q000276:immunology; D003429:Cross Reactions / Q000187:drug effects; D004195:Disease Models, Animal; D015195:Drug Design; D005098:Exotoxins / Q000276:immunology; D007114:Immunization; D007956:Leukocidins / Q000737:chemistry / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D055503:Protein Multimerization / Q000187:drug effects; D055550:Protein Stability / Q000187:drug effects; D058767:Protein Unfolding / Q000187:drug effects; D017386:Sequence Homology, Amino Acid; D013211:Staphylococcus aureus / Q000187:drug effects / Q000276:immunology*; D013696:Temperature; D014613:Vaccines, Attenuated / Q000737:chemistry / Q000276:immunology*; D022223:Vaccines, Subunit / Q000737:chemistry / Q000276:immunology*
chemical_list: D000276:Adjuvants, Immunologic; D000596:Amino Acids; D057134:Antibodies, Neutralizing; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D005098:Exotoxins; D007956:Leukocidins; D050505:Mutant Proteins; C078284:Panton-Valentine leukocidin; D014613:Vaccines, Attenuated; D022223:Vaccines, Subunit; C108483:leukocidin S-component protein, Staphylococcus; C074300:LukF protein, Staphylococcus aureus