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Polypropylene glycol is a selective binding inhibitor for LTA and other structurally related TLR2 agonists

Christian Draing1, Stephanie Traub, Susanne Deininger

  • 1Biochemical Pharmacology, University of Konstanz, Konstanz, Germany.

European Journal of Immunology
|February 13, 2008
PubMed

Insights

Polypropylene glycol (PPG) inhibits lipoteichoic acid (LTA) from inducing cytokines. PPG 1200 effectively blocks Toll-like receptor 2 (TLR2) agonist responses without cytotoxicity, directly binding LTA.

Area of Science:

  • Immunology
  • Microbiology
  • Biochemistry

Background:

  • Bacterial lipoteichoic acid (LTA) is a potent immune stimulant.
  • Polypropylene glycol (PPG) is used in bacterial cultures but can reduce LTA's immunogenicity.
  • The mechanism by which PPG affects LTA's cytokine-inducing capacity is unclear.

Purpose of the Study:

  • To investigate the inhibitory effects of various glycols on LTA-induced cytokine production in human blood.
  • To determine the specificity and mechanism of PPG's inhibitory action on Toll-like receptor (TLR) signaling.

Main Methods:

  • Testing multiple glycols for inhibition of cytokine induction by Staphylococcus aureus LTA in human blood.
  • Evaluating PPG 1200's effect on cytokine induction by different TLR2 and TLR4 agonists.
  • Utilizing flow cytometry and 1H-NMR to assess PPG-LTA interactions.
  • Conducting sequential incubation experiments to determine binding targets (LTA vs. cellular structures).

Main Results:

  • PPG 1200 was the most effective glycol inhibitor, suppressing TNF, IL-1beta, IL-6, IL-8, IL-10, and TGF-beta induction by LTA without cytotoxicity.
  • PPG 1200 inhibited TNF induction by Staphylococcus aureus and TLR2 agonists but not by Escherichia coli or TLR4 agonists.
  • Flow cytometry and NMR data indicated PPG binds directly to LTA.
  • Experiments confirmed PPG binds LTA, not blood cells, to exert its inhibitory effect.

Conclusions:

  • PPG 1200 is a novel inhibitor of cytokine induction mediated by TLR2 agonists.
  • PPG 1200 directly interacts with LTA, preventing its ability to stimulate the immune response via TLR2.

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