Fusion of the Fc part of human IgG1 to CD14 enhances its binding to Gram-negative bacteria and mediates phagocytosis by Fc receptors of neutrophils

András Vida, Bart Bardoel, Fin Milder, László Majoros, Andrea Sümegi, Attila Bácsi, G. Vereb, Kok P M Van Kessel, Jos A G Van Strijp, P. Antal-Szalmás

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Microbial resistance to antimicrobial drugs is promoting a search for new antimicrobial agents that target highly conservative structures of pathogens. Human CD14 - a known pattern recognition receptor (PRR) which recognizes multiple ligands from different microbes might be a worthy candidate. The aim of our work was to create a CD14/Fc dimer protein and evaluate its whole bacteria binding and opsonizing capabilities. Fusion of CD14 with the fragment crystallisable (Fc) part of human IgG1 could not only lead to an artificial opsonin but the dimerization through the Fc part might also increase its affinity to different ligands. Human CD14 and the Fc part of human IgG1 was fused and expressed in HEK293 cells. A histidine tagged CD14 (CD14/His) was also expressed as control. Using flow cytometry we could prove that CD14/Fc bound to whole Gram-negative bacteria, especially to short lipopolysaccharide (Ra and Re) mutants, and weak interaction was observed between the fusion protein and . Listeria monocytogenes. Other Gram-positive bacteria and fungi did not show any association with CD14/Fc. CD14/His showed about 50-times less potent binding to Gram-negative bacteria. CD14/Fc acted as an opsonin and enhanced phagocytosis of these bacteria by neutrophil granulocytes, monocyte-derived macrophages and dendritic cells. Internalization of bacteria was confirmed by trypan blue quenching and confocal microscopy. On neutrophils the Fc part of the fusion protein was recognized by Fc receptors (CD16, CD32), as determined by blocking experiments. CD14/Fc enhanced the killing of bacteria in an ex vivo whole blood assay. Our experiments confirm that PRR/Fc fusion proteins can give a boost to FcR dependent phagocytosis and killing provided the antimicrobial part binds efficiently to microbes.

Original languageEnglish
Pages (from-to)31-39
Number of pages9
JournalImmunology Letters
Volume146
Issue number1-2
DOIs
Publication statusPublished - Aug 30 2012

Fingerprint

Gram-Negative Bacteria
Phagocytosis
Neutrophils
Immunoglobulin G
Opsonin Proteins
Bacteria
Pattern Recognition Receptors
Proteins
Ligands
Trypan Blue
HEK293 Cells
Listeria monocytogenes
Dimerization
Gram-Positive Bacteria
Microbial Drug Resistance
Anti-Infective Agents
Histidine
Granulocytes
Confocal Microscopy
Dendritic Cells

Keywords

  • CD14
  • Fc
  • Gram-negative bacteria
  • Opsonization
  • Phagocytosis

ASJC Scopus subject areas

  • Immunology
  • Immunology and Allergy

Cite this

Fusion of the Fc part of human IgG1 to CD14 enhances its binding to Gram-negative bacteria and mediates phagocytosis by Fc receptors of neutrophils. / Vida, András; Bardoel, Bart; Milder, Fin; Majoros, László; Sümegi, Andrea; Bácsi, Attila; Vereb, G.; Van Kessel, Kok P M; Van Strijp, Jos A G; Antal-Szalmás, P.

In: Immunology Letters, Vol. 146, No. 1-2, 30.08.2012, p. 31-39.

Research output: Contribution to journalArticle

Vida, András ; Bardoel, Bart ; Milder, Fin ; Majoros, László ; Sümegi, Andrea ; Bácsi, Attila ; Vereb, G. ; Van Kessel, Kok P M ; Van Strijp, Jos A G ; Antal-Szalmás, P. / Fusion of the Fc part of human IgG1 to CD14 enhances its binding to Gram-negative bacteria and mediates phagocytosis by Fc receptors of neutrophils. In: Immunology Letters. 2012 ; Vol. 146, No. 1-2. pp. 31-39.
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AU - Sümegi, Andrea

AU - Bácsi, Attila

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