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Clinical and Vaccine Immunology, August 2009, p. 1187-1195, Vol. 16, No. 8
1071-412X/09/$08.00+0     doi:10.1128/CVI.00115-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Lipoprotein Lipase and Hydrofluoric Acid Deactivate Both Bacterial Lipoproteins and Lipoteichoic Acids, but Platelet-Activating Factor-Acetylhydrolase Degrades Only Lipoteichoic Acids{triangledown}

Ho Seong Seo and Moon H. Nahm*

University of Alabama at Birmingham, Birmingham, Alabama 35294

Received 13 March 2009/ Returned for modification 6 May 2009/ Accepted 15 June 2009

To identify the Toll-like receptor 2 ligand critically involved in infections with gram-positive bacteria, lipoprotein lipase (LPL) or hydrogen peroxide (H2O2) is often used to selectively inactivate lipoproteins, and hydrofluoric acid (HF) or platelet-activating factor-acetylhydrolase (PAF-AH) is used to selectively inactivate lipoteichoic acid (LTA). However, the specificities of these chemical reactions are unknown. We investigated the reaction specificities by using two synthetic lipoproteins (Pam3CSK4 and FSL-1) and LTAs from pneumococci and staphylococci. Changes in the structures of the two synthetic proteins and the LTAs were monitored by mass spectrometry, and biological activity changes were evaluated by measuring tumor necrosis factor alpha production by mouse macrophage cells (RAW 264.7) following stimulation. PAF-AH inactivated LTA without reducing the biological activities of Pam3CSK4 and FSL-1. Mass spectroscopy confirmed that PAF-AH monodeacylated pneumococcal LTA but did not alter the structure of either Pam3CSK4 or FSL-1. As expected, HF treatment reduced the biological activity of LTA by more than 80% and degraded LTA. HF treatment not only deacylated Pam3CSK4 and FSL-1 but also reduced the activities of the lipoproteins by more than 60%. Treatment with LPL decreased the biological activities by more than 80%. LPL also removed an acyl chain from the LTA and reduced its activity. Our results indicate that treatment with 1% H2O2 for 6 h at 37°C inactivates Pam3CSK4, FSL-1, and LTA by more than 80%. Although HF, LPL, and H2O2 treatments degrade and inactivate both lipopeptides and LTA, PAF-AH selectively inactivated LTA with no effect on the biological and structural properties of the two lipopeptides. Also, the ability of PAF-AH to reduce the inflammatory activities of cell wall extracts from gram-positive bacteria suggests LTA to be essential in inflammatory responses to gram-positive bacteria.

* Corresponding author. Mailing address: University of Alabama at Birmingham, BBRB 614, 1530 Third Avenue South, Birmingham, AL 35294-2170. Phone: (205) 934-0163. Fax: (205) 975-2149. E-mail: nahm{at}uab.edu

{triangledown} Published ahead of print on 24 June 2009.

Clinical and Vaccine Immunology, August 2009, p. 1187-1195, Vol. 16, No. 8
1071-412X/09/$08.00+0     doi:10.1128/CVI.00115-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





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