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* Department of Nanostructure and Advanced Materials, Kagoshima University, Kagoshima, Japan;
Department of Infectious Diseases, International Medical Center of Japan, Tokyo, Japan; and
Mikrobielle Genetik, Universität Tübingen, Tübingen, Germany
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Abstract |
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lgt) mutant, which lacks palmitate-labeled lipoproteins, and its complemented strain and evaluated the activity of LTA molecule. LTA fraction was prepared by butanol extraction of the bacteria followed by hydrophobic interaction chromatography. Although all LTA fractions activated cells through TLR2, the LTA from lgt mutant was 100-fold less potent than those of wild-type and complemented strains. However, no significant structural difference in LTA was observed in NMR spectra. Further, alanylation of LTA molecule showed no effect in immunobiological activity. These results showed that not LTA molecule but lipoproteins are dominant immunobiologically active TLR2 ligand in S. aureus. |
Introduction |
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The innate immune system plays essential roles in host defense against bacterial infection. The system recognizes bacterial components known as pathogen-associated molecular patterns and controls immune responses. TLR, a type I transmembrane protein, has been found to be a major signaling receptor for pathogen-associated molecular patterns (8). To date, more than 10 members of the TLR family have been discovered and many ligands were identified. TLR4, the most characterized member of the family, in combination with an adapter molecule MD-2, has been shown to recognize LPS, an outer membrane component of Gram-negative bacteria (9, 10). TLR9 has been reported to be involved in immune responses to unmethylated CpG DNA (11) and TLR3 and TLR7/8 sense viral dsRNA and ssRNA (12, 13). Activation of TLR5 has been demonstrated to be mediated by bacterial flagellin (14). Bacterial lipoproteins have been found to be stimuli of TLR2 subfamily (TLR1, 2, and 6) (15, 16).
TLR2 has also been shown to play a crucial role in the host response to LTA fraction (17). Morath et al. (18, 19) also reported that LTA molecule from S. aureus was a potent stimulus of cytokine release. However, we have demonstrated that LTA from enterococci has no cytokine-producing activity. Fukase et al. (20, 21) prepared chemically synthetic glycoconjugates having fundamental structures of LTA from Enterococcus hirae and Streptococcus pyogenes and their glycolipid anchor parts, and Takada et al. (22) demonstrated that these synthetic compounds exhibited no immunostimulating activities. Furthermore, we found that a LTA fraction extracted from E. hirae can be separated into two subfractions, a small amount of cytokine-inducing active fractions and an inactive major compound, and the structure of the inactive compound is identical to that of LTA (23, 24). We also found that the enterococcal active fractions activate immune cells through TLR2 (25). These results suggest that the contaminating minor components in LTA fraction is responsible for the immunostimulant for TLR2.
We previously found that lipoproteins from S. aureus stimulate activation of immune cells through TLR2 (26). Furthermore, the activity of LTA fraction was decreased by lipoprotein lipase digestion, indicating that the fraction was contaminated by lipoproteins. Recently, Stoll et al. (27) constructed a lipoprotein diacylglycerol transferase (lgt) deletion mutant of S. aureus, which is unable to carry out lipid modification of prolipoproteins. It has been demonstrated that the mutant completely lacked palmitate-labeled lipoproteins and that the cells and crude lysate induced much less proinflammatory cytokines than the wild type (WT). These results suggested that lipoproteins in S. aureus appear to be the predominant stimuli for the immune system. However, it is still unknown whether LTA molecule from S. auerus is inactive. In the present study, we prepared LTA fractions from the S. aureus lgt deletion mutant strain and analyzed its immunobiological activity and structure.
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Materials and Methods |
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S. aureus SA113 WT, SA113 lgt::ermB (lgt), and SA113 lgt::ermB +pRBlgt (+pRB) (27) organisms were grown in Mueller-Hinton II cation adjusted broth (BD Biosciences) at 37°C for 6 h with constant shaking. LTA factions of S. aureus were prepared by aqueous 1-butanol (BuOH) extraction method (19). Briefly, the cells were suspended in BuOH/water (1:1, v/v), and the mixture was stirred at room temperature for 30 min and centrifuged to separate aqueous phase from BuOH and cell debris. The aqueous phase was concentrated by evaporator, dialyzed for 3 days, and lyophilized to give crude LTA fraction. Crude fractions were further subjected to hydrophobic interaction chromatography on Octyl Sepharose 4FF (Amersham Biosciences). The fraction dissolved in 0.1 M ammonium acetate buffer (pH 4.7) containing 15% (v/v) 1-propanol (PrOH) was loaded to an Octyl Sepharose column (
1.5 x 25 cm) equilibrated with the same buffer. The column was first eluted with 30 ml of equilibration buffer, with a linear PrOH gradient from 15 to 60% (v/v; 40 ml each), and then with 60% PrOH in the buffer. The fractions were collected every 3 ml (8 min) and analyzed by phosphorus content and NF-
B activation in Ba/mTLR2 cells described below. Bound fractions were combined, concentrated by evaporator, dialyzed, and lyophilized to give LTA fraction.
SA113 and SA113 lgt::ermB were also cultured in Brain heart infusion broth (BD Biosciences) adjusted to pH 6.0 with hydrochloric acid. LTA fractions were prepared by a similar method as above without dialysis steps. The fraction was again subjected to a column chromatography on Octyl Sepharose (1.5 x 20 cm) to separate a LTA and other active compounds. Hydrolysis of LTA molecules was performed with 47% aqueous hydrofluoric acid (HF) at 4°C for 24 h.
To extract a fraction containing lipoproteins, S. aureus cells were subjected to Triton X-114 (TX-114) phase partitioning, according to the method as reported (28). Briefly, the cells were suspended in PBS containing protease inhibitor mixture Complete mini (Roche Diagnostics) and combined with 1/10 volume of 10% aqueous TX-114. The mixture was rotated at 4°C for 1 h and then cell debris were centrifuged off. The supernatant was incubated and centrifuged at 37°C to separate TX-114 from aqueous phase. The upper aqueous phase was treated again with TX-114. Crude lipoprotein fraction was precipitated from TX-114 phase by addition of excess methanol.
Analytical methods
Phosphorous contents were measured by the method of Bartlett (29). SDS-PAGE was performed by the Tris-glycine method (30) using a mini PAGE chamber AE-6530 and an AE-8450 power supply (Atto Bioscience) with a 15% gel. Proteins were visualized by Coomassie brilliant blue staining and acidic materials, such as LTA, by alcian blue (AB) staining. Proton nuclear magnetic resonance (1H NMR) spectra were measured using a ECA-600 spectrometer (JEOL) at 600 MHz at 293 K in D2O. The chemical shifts are expressed in 
value with HOD ( 4.67) as the internal standard.
Luciferase assays
Ba/F3 cells stably expressing p55IgLuc, a NF-B/DNA binding activity-dependent luciferase reporter construct (Ba/B), murine TLR2 and the p55IgLuc reporter construct (Ba/mTLR2), and murine TLR4/MD-2 and the p55IgLuc reporter construct (Ba/mTLR4/mMD-2) were provided by Prof. K. Miyake (Institute of Medical Science, University of Tokyo, Tokyo, Japan). NF-B-dependent luciferase activity in these cells was determined as described previously (31). Briefly, cells were inoculated onto each well of a 96-well flat-bottom plate (BD Biosciences) at 1 x 105 cells in 80 µl of RPMI 1640 (Sigma-Aldrich) supplemented with 10% FBS (MBL) and stimulated with the indicated concentrations of the test specimens. After 4 h of incubation at 37°C in humidified air containing 5% CO2, 80 µl of Bright-Glo luciferase assay reagent (Promega) was added to each well, and luminescence was quantified with a luminometer ARVO SX multilabel counter (PerkinElmer). Results are shown as relative luciferase activity, which was the ratio of stimulated activity to nonstimulated activity, in each cell line.
Cytokine assay
Eight-week-old male BALB/c and C57BL/6 mice were obtained from Kyudo. The animals received humane care in accordance with our institutional guidelines and the legal requirements of Japan. Elicited peritoneal macrophages were obtained from mice 3 days after i.p. inoculation of 1.0 ml of 3% sterile Brewer’s thioglycolate broth (BD Biosciences). Peritoneal exudate cells (PEC) were centrifuged and suspended in RPMI 1640 supplemented with 10% FBS (Medical and Biological Laboratories). A mouse macrophage cell line, J774A.1 (Health Science Research Resource Bank), was cultured in DMEM (Sigma-Aldrich) supplemented with 10% FBS and also used for the assay. These cells were then distributed to 96-well plate at 2 x 105 cells/ml, after which they were incubated for 2 h at 37°C in humidified air containing 5% CO2. Each dish was washed twice with PBS to remove nonadherent cells, and those attached to the dish served as peritoneal macrophages. Cells were stimulated with the indicated concentrations of the test specimens in culture medium supplemented with 10% FBS for 4 h at 37°C. After incubation, culture supernatants were collected and used for the cytokine assay using an ELISA kit for secreted TNF-
(R&D Systems). The concentration of secreted TNF- from cells were determined using a standard curve of rTNF- prepared in each assay. TNF- concentrations in different experimental groups were analyzed for statistical significance by using Welch’s t test.
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Results |
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lgt is less active than those from WT and the complemented strain
It has been reported that S. aureus SA113 lgt mutant and its crude cell lysate induce fewer proinflammatory cytokines and chemokines than its WT strain (27). Thus, the effect of the lgt deletion to immunostimulatory activity of LTA fraction was investigated. Crude LTA fractions were prepared by BuOH extraction, which was used for the LTA preparation by Morath et al. (18) from S. aureus SA113 WT, lgt, and +pRB strains. The yield of BuOH extracts were 0.8, 1.1, and 2.2% based on respective lyophilized cells and designated as SaWT-Bu, Salgt-Bu, and Sa+pRB-Bu, respectively. SaWT-Bu and Sa+pRB-Bu stimulated TNF- production in J774A.1 at the concentration of 100 ng/ml (Fig. 1). In contrast, only slight TNF- production was observed in J774A.1 stimulated with 10,000 ng/ml Salgt-Bu (Fig. 1), showing that the activity of Salgt-Bu is 100-fold lower than those of the others. All the BuOH extracts activated Ba/mTLR2 but not Ba/B and Ba/mTLR4/mMD-2 (Fig. 2A), and the TLR2-mediated activity was dose dependent (Fig. 2B). These results suggested that TLR2 recognizes the extracts. The BuOH extracts were then subjected to hydrophobic interaction chromatography on Octyl Sepharose 4FF to separate LTA fraction from nucleic acids and cytoplasmic proteins. As shown in Fig. 3, A–C, LTA fraction was eluted at ca
40–50% PrOH concentration. The yield of LTA fraction were 6.5% (based on SaWT-Bu), 4.5% (based on Salgt-Bu), and 7.3% (based on Sa+pRB-Bu) and designated as SaWT-OS, Salgt-OS, and Sa+pRB-OS, respectively. SDS-PAGE profiles showed that all fraction contained AB-positive LTA (Fig. 3, D–F). SaWT-OS and Sa+pRB-OS stimulated TNF- production in J774A.1 at the concentration of 10 ng/ml, whereas Salgt-OS stimulated TNF- production only at concentrations > 1,000 ng/ml (Fig. 4), showing that the LTA fraction from lgt deletion mutant is 100-fold less active than those from the others. These results suggested that lipoproteins are responsible for most of the activity of S. aureus LTA fractions.
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Morath et al. (18) reported that alanine substituent in LTA plays the critical role for the biological activity of LTA from S. aureus. Deliberate hydrolysis of alanine at pH 8.5 significantly reduced the activity of LTA. Thus, structures of the LTA fractions were analyzed by 1H NMR to determined the alanine substitution. As shown in Fig. 5, A–C, no distinct difference was observed among the three LTA fractions. Methyl ( 0.60–0.75) and methylene ( 1.0–1.2) signals of fatty acids and methylene and methine ( 3.7–3.9) of glycerol residues showed a S. aureus-type LTA structure. However, there is scarce signals of alanine attached to glycerol moieties, methyl ( 1.45) and methine ( 4.12), in alanine residue and methine ( 5.22) of alanine-substituted glycerol, indicating the absence of alanine substitution in these LTA fractions. Previously, it has been shown that in S. aureus SA113 75% of the glycerol residues of LTA was esterified with D-alanine, whereas the corresponding S. aureus dlt mutant completely lacked LTA D-alanylation (32). The dltABCD operon encodes the genes for incorporation of D-alanine in teichoic acids. Furthermore, it is reported that the pH of culture medium affects the alanine ester content of LTA in S. aureus (33). LTA from organisms growing at high pH (pH 8.10) contained very little alanine ester, whereas high alanylation was observed at low pH (pH 6.07). Thus LTA fractions, named as SaWT6-OS and Salgt6-OS, were prepared by a similar method from S. aureus SA113 WT and lgt strains grown at pH 6. In the NMR spectra, significant signals of alanines substituted at O2-position of glycerols in LTA was found in SaWT6-OS and Salgt6-OS (Fig. 5, D and E). SaWT6-OS, as well as SaWT-OS, stimulated TNF- production in J774A.1, whereas the production by Salgt6-OS or Salgt-OS were 100- to 1000-fold less active (Fig. 6A). Salgt-OS or Salgt6-OS also induced less TNF- production than the fractions from WT in murine PEC (Fig. 6, B and C). The activity of SaWT6-OS was comparable to SaWT-OS, and no significant enhancement was observed between Salgt6-OS and Salgt-OS. These results indicated that the alanylation of LTA molecule showed no significant effect on the immunobiological activity.
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lgt mutant are not LTA
Salgt6-OS still weakly activated Ba/TLR2 cells (data not shown), indicating that the fraction contained some TLR2-activating compound(s). Therefore, the fraction was again separated by hydrophobic interaction chromatography. The elution pattern of phosphate-rich LTA fraction was not the same as that of TLR2-active fraction (Fig. 7A). Salgt6-OS hydrolyzed with HF to cleave phosphodiester bonds in LTA molecules was also separated by the column. Hydrolyzed LTA fragments, phosphate, and derivatives of phosphoglycerol eluted as pass-through fraction, whereas TLR2-active fraction eluted at a similar PrOH concentration as that of Salgt6-OS (Fig. 7B). These results suggested that the fraction contains unknown TLR2-activating compound other than LTA molecule.
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Discussion |
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lgt mutant, Salgt-OS, is 100-fold less potent than those of WT, SaWT-OS (Figs. 1 and 4). These observations clearly show that most of the activity of LTA fraction obtained from natural sources is attributable to the lipoproteins contaminated in the fraction. We recently demonstrated that a mAb, mAbEh1, established by immunization of the active subfraction of E. hirae LTA fraction, neutralized the activity not only of LTA fraction from E. hirae and S. aureus but also immunobiologically active bacterial lipopeptides, Pam3CSK4 and FSL-1 (M. Hashimoto, submitted for publication). These results strongly support the above consideration. Some LPS preparations have been shown to slightly induce a signal via TLR2, in addition to TLR4 (34, 35). The activity is proven to be the result of lipoprotein contamination in these preparations (31, 36). LPS is an amphiphile, which consists of hydrophobic glycolipid moiety and hydrophilic polysaccharide, and considered to work as a detergent to coextract lipoproteins from bacterial cells in a LPS extraction step. Since LTA is also an amphiphile, LTA may play a similar role as LPS.
For many decades, it has been controversial as to whether the LTA molecule exhibits immunostimulating activities. Recently, Morath et al. (18) suggested that partial degradation of LTA during the separation steps contributed to the activity. In our previous experiments, inactive LTA was prepared by the phenol-hot water extraction method (23, 24), whereas Morath et al. (18) obtained LTA by amended BuOH-water extraction and found that D-alanine contents in phenol-extracted LTA is less than those in BuOH one. They also showed that alkaline hydrolysis of the active LTA, which resulted in a loss of D-alanine substituent in LTA, reduced its activity. Thus, they concluded that D-alanine content in a LTA molecule is critical for the activity of LTA from S. aureus. However, we demonstrated here that D-alanine content has no significant effect on the activity of LTA fraction. We compared the levels of alanine substitution in LTA obtained from S. aureus grown in the different conditions. All LTA fractions cultured in neutral pH scarcely contained alanine substituent (Fig. 5, A–C). However, SaWT-OS and Sa+pRB-OS exhibited potent immunostimulating activities (Fig. 4), whereas both LTA fractions from pH 6 medium contained considerable alanine substituent (Fig. 5, D and E). Despite alanine substitution, Salgt6-OS exhibited significantly low activity compared with SaWT6-OS (Fig. 6). In the fraction from WT strain, SaWT-OS and SaWT6-OS, the LTA alanylation showed no significant effects on TNF- production (Fig. 6). These results prove that not the D-alanine content but the lipoprotein contaminant is responsible for the activities of LTA fractions. The alanylation may affect some of LTA properties, but the activity of the fraction is independent of alanylation. The previous observation may be artificial due to the process of alkaline hydrolysis.
Immunologically inactive LTA has not been obtained from S. aureus. We have previously purified inactive LTA from E. hirae using hydrophobic interaction, followed by anion exchange chromatography (23). Morath et al. (18) purified S. aureus LTA by a similar method and found that cytokine-inducing activity coeluted with phosphate derived from LTA. Therefore, they concluded that LTA is a potent stimuli for cytokine release in immune cells and that a contamination by other bacterial components in the S. aureus LTA is unlikely. We were also unable to isolate a completely inactive LTA from S. aureus even if using lgt mutant (Fig. 3). However, the precise elution of Salgt6-OS on Octyl Sepharose column showed that TLR2 activity eluted broadly, but most of the activity was separated from a sharp LTA-derived phosphate peak (Fig. 7A). Furthermore, the active compound eluted at similar fractions after HF degradation of LTA (Fig. 7B). HF hydrolyzed phosphodiester linkages in LTA and cleaved into hydrophilic inorganic phosphate and derivatives of phosphoglycerol and hydrophobic diacylglycerol-type glycolipid; the former was shown to be inactive (Fig. 7B), and the latter was also demonstrated to be inactive at least in our assay system using chemically synthetic compound (M. Hashimoto, submitted for publication). The activity of the contaminant after LTA degradation seems to be diminished (Fig. 7B) compared with that before degradation (Fig. 7A). It may be caused by loss of solubilization capacity of LTA. These results suggest that fraction contains some TLR2-activating contaminants, but it is independent of LTA molecule.
The minor active contaminants in the LTA fraction of lgt mutant are still unidentified. The TLR2-activating compound was also extracted by TX-114 phase partitioning of the mutant (data not shown). TX-114 is usually used for extraction of hydrophobic compounds. The chromatographic property and extraction behavior suggested that the compounds may be acylated. Recently, Uehori et al. (37) reported that monoacylated muramyldipeptide derivatives, which mimic peptidoglycan structure of bacillus Calmette-Guerin, activated DC through TLR2/TLR4. Since unmodified muramyldipeptide did not activate cells via TLR but through NOD2 (38), specific acylation might be required for TLR activation. Furthermore, the contaminants activated J774A.1 and PEC from C57BL/6 but not PEC from BALB/c (Fig. 6). A distinct set of gene expression may be required for cells activation. It is possible that small amount of hydrophobic acylated compounds are present in the LTA fraction.
In conclusion, we demonstrated here that LTA fraction obtained from S. aureus lgt mutant is 100-fold less potent than those of WT, and the activity is independent from extraction methods of the fraction and D-alanine contents in LTA molecule. Lipoproteins but not LTA molecule are the predominant TLR2-activating components in S. aureus.
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Acknowledgments |
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Disclosures |
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Footnotes |
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1 This work was supported in part by Grants-in-Aid for Encouragement of Young Scientists (B) (16710160) from the Ministry of Education, Culture, Sports, Science and Technology and for Scientific Research (C) (17510179) from the Japanese Society of the Promotion of Science. 
2 Address correspondence and reprint requests to Dr. Masahito Hashimoto, Department of Nanostructure and Advanced Materials, Kagoshima University, Korimoto 1-21-40, Kagoshima 890-0065, Japan. E-mail address: hassy{at}eng.kagoshima-u.ac.jp
3 Abbreviations used in this paper: LTA, lipoteichoic acid; AB, alcian blue; BuOH, 1-butanol; HF, hydrofluoric acid; NMR, nuclear magnetic resonance; PEC, peritoneal exudate cell; PrOH, 1-propanol; TX-114, Triton X-114; WT, wild type.
Received for publication February 27, 2006. Accepted for publication June 19, 2006.
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References |
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B by Toll-like receptor 3. Nature 413: 732-738. [Medline]This article has been cited by other articles:
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 |
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 |
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|
 |
|
 H. J. Warshakoon, M. R. Burns, and S. A. David Structure-Activity Relationships of Antimicrobial and Lipoteichoic Acid-Sequestering Properties in Polyamine Sulfonamides Antimicrob. Agents Chemother., January 1, 2009; 53(1): 57 - 62. [Abstract] [Full Text] [PDF]
|
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|
|
 |
|
 S. Lebeer, J. Vanderleyden, and S. C. J. De Keersmaecker Genes and Molecules of Lactobacilli Supporting Probiotic Action Microbiol. Mol. Biol. Rev., December 1, 2008; 72(4): 728 - 764. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Parcina, C. Wendt, F. Goetz, R. Zawatzky, U. Zahringer, K. Heeg, and I. Bekeredjian-Ding Staphylococcus aureus-Induced Plasmacytoid Dendritic Cell Activation Is Based on an IgG-Mediated Memory Response J. Immunol., September 15, 2008; 181(6): 3823 - 3833. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Machata, S. Tchatalbachev, W. Mohamed, L. Jansch, T. Hain, and T. Chakraborty Lipoproteins of Listeria monocytogenes Are Critical for Virulence and TLR2-Mediated Immune Activation J. Immunol., August 1, 2008; 181(3): 2028 - 2035. [Abstract] [Full Text] [PDF]
|
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|
|
|
|
P. Henneke, S. Dramsi, G. Mancuso, K. Chraibi, E. Pellegrini, C. Theilacker, J. Hubner, S. Santos-Sierra, G. Teti, D. T. Golenbock, et al. Lipoproteins Are Critical TLR2 Activating Toxins in Group B Streptococcal Sepsis J. Immunol., May 1, 2008; 180(9): 6149 - 6158. [Abstract] [Full Text] [PDF]
|
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|
|
 |
|
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|
|
|
|
|
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|
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 |
|
 C. Hermann Review: Variability of host pathogen interaction Innate Immunity, August 1, 2007; 13(4): 199 - 218. [Abstract] [PDF]
|
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|
|
 |
|
 A. Grundling and O. Schneewind Synthesis of glycerol phosphate lipoteichoic acid in Staphylococcus aureus PNAS, May 15, 2007; 104(20): 8478 - 8483. [Abstract] [Full Text] [PDF]
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|
|
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M. Hashimoto, M. Furuyashiki, R. Kaseya, Y. Fukada, M. Akimaru, K. Aoyama, T. Okuno, T. Tamura, T. Kirikae, F. Kirikae, et al. Evidence of Immunostimulating Lipoprotein Existing in the Natural Lipoteichoic Acid Fraction Infect. Immun., April 1, 2007; 75(4): 1926 - 1932. [Abstract] [Full Text] [PDF]
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S. von Aulock, T. Hartung, and C. Hermann Comment on "Not Lipoteichoic Acid but Lipoproteins Appear to Be the Dominant Immunobiologically Active Compounds in Staphylococcus aureus" J. Immunol., March 1, 2007; 178(5): 2610 - 2610. [Full Text] [PDF]
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I. Bekeredjian-Ding, S. Inamura, T. Giese, H. Moll, S. Endres, A. Sing, U. Zahringer, and G. Hartmann Staphylococcus aureus Protein A Triggers T Cell-Independent B Cell Proliferation by Sensitizing B Cells for TLR2 Ligands J. Immunol., March 1, 2007; 178(5): 2803 - 2812. [Abstract] [Full Text] [PDF]
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M. Hashimoto, M. Furuyashiki, and Y. Suda Response to Comment on "Not Lipoteichoic Acid but Lipoproteins Appear to Be the Dominant Immunobiologically Active Compounds in Staphylococcus aureus" J. Immunol., March 1, 2007; 178(5): 2610 - 2611. [Full Text] [PDF]
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 F. Garcia-del Portillo and P. Cossart An Important Step in Listeria Lipoprotein Research J. Bacteriol., January 15, 2007; 189(2): 294 - 297. [Full Text] [PDF]
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