The use of monoclonal antibodies for studying the biological properties of Staphylococcus aureus endo-β-N-acetylglucosaminidase

Maria C. Guardati, Carlos A. Guzmàn, Guiseppina LiPira, Gabriella Piatti, Federico Robbiati, Carla Pruzzo

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Abstract

Staphylococcus aureus endo-β-N-acetylglucosaminidase (SaG) has been suggested to function as a virulence determinant which interferes with the host cellular immune response. To further characterize the biological properties of SaG, monoclonal antibodies (mAbs) were raised against purified SaG. Four IgG1 subclass mAbs were obtained, none of which reacted with the reduced, sodium dodecyl sulphate pretreated or boiled enzyme. The ability of the mAbs to react with the enzymes present in supernatants obtained from 197 S. aureus strains indicated that they recognized epitopes which are highly conserved; bacteriolytic enzymes produced by staphylococci other than S. aureus did not show any cross-reactivity. After pretreatment of SaG with mAbs (mAb-SaG molar ratios varying from 1 to 20), it was shown that all selected mAbs caused, at a mAb: SaG molar ratio of 10, a 90% inhibition of SaG bacteriolytic activity and a statistically significant reduction of its ability to interfere with phagocytosis to human polymorphonuclear leukocytes. All selected mAbs reacted with several commercially available exo-β-N-acetylglucosaminidases; mAb C1/10-11 also reacted with chicken and turkey egg muramidases and, at a mAb:SaG molar ratio of 10, inhibited their bacteriolytic activity by 97%. This suggests that one or more epitopes present in the above exo-glucosaminidases and muramidases share some degree of homology with others present in SaG.

Original languageEnglish
Pages (from-to)73-79
Number of pages7
JournalFEMS Microbiology Letters
Volume112
Issue number1
Publication statusPublished - Aug 15 1993

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Keywords

  • Glucosaminidase
  • Monoclonal antibodies against Staphylococcus aureus glucosaminidase
  • Staphylococcus aureus
  • Virulence determinant

ASJC Scopus subject areas

  • Genetics
  • Molecular Biology
  • Applied Microbiology and Biotechnology
  • Microbiology

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