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Heavy chain-only antibodies and tetravalent bispecific antibody neutralizing Staphylococcus aureus leukotoxins

Benoît-Joseph Laventie1, Hendrik Jan Rademaker, Maher Saleh

  • 1Faculté de Médecine, Physiopathologie et Médecine Translationnelle, Institut de Bactériologie, Centre Hospitalier Régional Universitaire, Université de Strasbourg, 67000 Strasbourg, France.

Proceedings of the National Academy of Sciences of the United States of America
|September 21, 2011
PubMed

Insights

Humanized heavy chain-only antibodies (HCAb) effectively neutralize Panton-Valentine leukocidin (PVL) from Staphylococcus aureus. These antibodies show therapeutic potential by preventing toxin activity and reducing tissue damage in preclinical models.

Area of Science:

  • Microbiology
  • Immunology
  • Biotechnology

Background:

  • Panton-Valentine leukocidin (PVL) is a key virulence factor in Staphylococcus aureus, contributing to severe skin and soft tissue infections.
  • PVL is a pore-forming toxin composed of LukS-PV and LukF-PV, which targets host defense cells, leading to cell lysis.
  • Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains producing PVL are responsible for current outbreaks.

Purpose of the Study:

  • To develop and evaluate humanized heavy chain-only antibodies (HCAb) for neutralizing Staphylococcus aureus PVL.
  • To assess the therapeutic efficacy of these antibodies in preclinical models of PVL-mediated disease.

Main Methods:

  • Generation of humanized heavy chain-only antibodies (HCAb) against PVL components (LukS-PV and LukF-PV) in immunized transgenic mice.
  • In vitro characterization of antibody binding, toxin neutralization, and pore formation inhibition.
  • In vivo efficacy testing in a rabbit model of toxin-induced endophthalmitis.

Main Results:

  • Developed several high-affinity (nanomolar range) anti-PVL HCAb, including anti-LukS-PV and anti-LukF-PV antibodies.
  • All tested HCAb successfully prevented PVL binding and pore formation in vitro.
  • The anti-LukS-PV HCAb also demonstrated cross-neutralization activity against gamma-hemolysin C (HlgC).
  • In vivo studies showed that HCAb inhibited inflammatory responses and tissue damage, with a tetravalent bispecific HCAb exhibiting the best performance.

Conclusions:

  • Humanized heavy chain-only antibodies represent a promising therapeutic strategy against PVL-mediated Staphylococcus aureus infections.
  • Bispecific antibodies, in particular, demonstrate significant potential for enhanced therapeutic efficacy.
  • Targeting PVL with neutralizing antibodies can mitigate Staphylococcus aureus-related disease pathology.

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