Lactobacillus plantarum Lipoteichoic Acid Inhibits Oral Multispecies Biofilm.

INTRODUCTION: Apical periodontitis is an inflammatory disease in the periradicular region of teeth that results from infection by multispecies bacterial biofilm residing in the root canal system. In this study, we investigated whether Lactobacillus plantarum lipoteichoic acid (Lp.LTA) could inhibit multispecies oral pathogenic bacterial biofilm formation. METHODS: Highly pure and structurally intact Lp.LTA was purified from L. plantarum. Actinomyces naeslundii, Lactobacillus salivarius, Streptococcus mutans, and Enterococcus faecalis were co-cultured to form oral multispecies biofilm in the presence or absence of Lp.LTA on culture plates or human dentin slices. Preformed biofilm was treated with or without Lp.LTA, followed by additional treatment with intracanal medicaments such as calcium hydroxide or chlorhexidine digluconate. Confocal microscopy and crystal violet assay were performed to determine biofilm formation. Biofilm on human dentin slices was visualized with a scanning electron microscope. RESULTS: Biofilm formation of multispecies bacteria on the culture dishes was dose-dependently reduced by Lp.LTA compared with the nontreatment control group. Lp.LTA also inhibited multispecies biofilm formation on the dentin slices in a dose-dependent manner. Interestingly, Lp.LTA was shown to reduce preformed multispecies biofilm compared with the nontreatment group. Moreover, Lp.LTA potentiated the effectiveness of the intracanal medicaments in the removal of preformed multispecies biofilm. CONCLUSIONS: These results suggest that Lp.LTA is a potential anti-biofilm agent for treatment or prevention of oral infectious disease, including apical periodontitis, which is mainly caused by multispecies bacterial biofilm.

Effective cancer immunotherapy based on combination of TLR agonists with stimulation of phagocytosis.

Immunotherapy emerges as a fundamental approach in cancer treatment. Up to date, the efficacy of numerous different immunotherapies has been evaluated. The use of microorganisms or their parts for immune cell activation, referred to as Pathogen-Associated Molecular Patterns (PAMPs), represents highly promising concept. The therapeutic effect of PAMPs can be further amplified by suitable combination of different types of PAMPs such as Toll like receptor (TLR) agonists and phagocytosis activating ligands. Previously, we used the combination of phagocytosis activating ligand (mannan) and mixture of TLR agonists (resiquimod (R-848), poly(I:C), inactivated Listeria monocytogenes) for successful treatment of melanoma in murine B16-F10 model. In the present study, we optimized the composition and timing of previously used mixture. Therapeutic mixture based on well-defined chemical compounds consisted of mannan anchoring to tumor cell surface by biocompatible anchor for membranes (BAM) and TLR agonists resiquimod, poly(I:C), and lipoteichoic acid (LTA). The optimization resulted in (1) eradication of advanced stage progressive melanoma in 83% of mice, (2) acquisition of resistance to tumor re-transplantation, and (3) potential anti-metastatic effect. After further investigation of mechanisms, underlying anti-tumor responses, we concluded that both innate and adaptive immunity are activated and involved in these processes. We tested the efficacy of our treatment in Panc02 murine model of aggressive pancreatic tumor as well. Simultaneous application of agonistic anti-CD40 antibody was necessary to achieve effective therapeutic response (80% recovery) in this model. Our results suggest that herein presented immunotherapeutic approach is a promising cancer treatment strategy with the ability to eradicate not only primary tumors but also metastases.

Toll-like receptor (TLR) 2 agonists ameliorate indomethacin-induced murine ileitis by suppressing the TLR4 signaling.

BACKGROUND AND AIM: Few drugs have been found satisfactory in the treatment of nonsteroidal anti-inflammatory drugs (NSAIDs)-induced enteropathy. Toll-like receptor (TLR) 4 and aberrant leukocyte migration to the intestinal mucosa are reported to be involved in the pathology of intestinal enteropathy and TLR2 agonists have been found to evoke hyposensitivity to TLR4 stimulation in vitro. In this study, we investigated whether and how lipoarabinomannan (LAM) or lipoteichoic acid (LTA), TLR2 agonists, attenuated indomethacin (IND)-induced intestinal damage. METHODS: LAM (0.5 mg/kg) or LTA (15 mg/kg) was administered intraperitoneally to mice before IND (10 mg/kg) administration. Disease activity was evaluated macroscopically and histologically. In the migration analysis, fluorescence-labeled leukocyte movement in the intestinal microvessels was observed by intravital microscopy. Expression of P-selectin, MAdCAM-1, TLR2, TLR4, and F4/80 was observed immunohistochemically. In the in vitro analysis, RAW264.7 macrophage cells were preincubated with LAM and stimulated with lipopolysaccharide (LPS), and the mRNA expression levels of TLR4, tumor necrosis factor-α, and interleukin-12p40 were measured. RESULTS: Pretreatment with LAM or LTA significantly decreased IND-induced injury as well as decreased leukocyte infiltration. Pretreatment with LAM decreased IND-induced TLR4 expression on F4/80(+) macrophages, the level of P-selectin expression, and leukocyte migration in the small intestinal vessels. In the in vitro study, a single administration of LAM decreased TLR4 mRNA expression and inhibited the increase in mRNA expression of inflammatory cytokines by LPS in a dose-dependent manner. CONCLUSION: TLR2 agonists attenuated IND-induced small intestinal lesions and leukocyte infiltration probably by suppressing the TLR4 signaling pathway in tissue macrophages.

Cooperative effect of Bifidobacteria lipoteichoic acid combined with 5-fluorouracil on hepatoma-22 cells growth and apoptosis.

AIMS: To investigate the cooperative effect of Bifidobacteria lipoteichoic acid (BLTA) combined with 5-fluorouracil on tumor cells growth and apoptosis in mice bearing H22. METHODS: Hepatoma-22 (H22) cells were cultured in RPMI1640. Establish tumor-bearing mice model of liver cancer by injecting intraperitoneally 1×10(6)/mL cells into the above-mentioned Balb/c mice. 5-FU alone, BLTA alone or BLTA in combination with 5-FU were used to treat tumor-bearing mice. The tumor size were observed and measured regularly. The growth-inhibiting rate (IR) of tumor was detected. Real-Time PCR and Western blot were used to detect Bcl-2, Bax and Caspase-3 expressions of mRNA and protein in tumor tissue of tumor-bearing mice. Detection of apoptotic cells in tumor tissue by HE staining analysis. Detection of the organ index was for evaluate the added-activity of immune organs in mouse. FCM was used to detect T subgroup ratio of spleen cells of tumor-bearing mice. Expression change of mRNA and proteins of Foxp3 and TIM-3 were detected by Real-Time PCR and Western blot in tumor-bearing mice tumor tissue. RESULTS: BLTA and 5-FU significantly inhibited the proliferation of tumor and induced obvious apoptosis, the combined effects were greater than those of the individual agents (P<0.01). The underlying molecular mechanism of apoptotic process could be up-regulation of Bax and down-regulation of Bcl-2 and Caspase-3. The HE staining indicated that combined treat could both induce tissue cells necrosis and increase immune cells infiltration. Organ index showed that BLTA can enhance the proliferation of immune organs. The ratio of CD4(+)CD25(+) Treg significantly decreased and CD4(+) T cell increased in BLTA and 5-FU group (P<0.01). Compared to NS group, mRNA and proteins expression of Foxp3 and TIM-3 down regulated in BLTA and 5-FU group (P<0.01). CONCLUSIONS: These results show that combined effects of Bifidobacteria lipoteichoic acid and 5-FU on H22 cells were superior to the individual. The combination did not only increase anti-tumor effect, but also could alleviate the side effects of chemotherapy, with inhibiting TIM-3/TIM-3L pathway, cutting down immunosuppressive activity of CD4(+)CD25(+) Treg and enhancing cell-mediated immunity.

Lipoteichoic acid from Lactobacillus rhamnosus GG as an oral photoprotective agent against UV-induced carcinogenesis.

Probiotics are live micro-organisms that when administered in adequate amounts confer a health benefit on the host. Cell surface molecules of these micro-organisms are being studied in relation to their ability to interact with the host. The cell wall of lactobacilli possesses lipoteichoic acids (LTA) which are molecules with immunomodulatory properties. UV radiation (UVR) has been proposed as the main cause of skin cancer because of its mutagenic and immunosuppressive effects. Photoprotection with some nutrition interventions including probiotics has recently been shown. The aim of the present study was to investigate whether the oral administration of purified LTA from Lactobacillus rhamnosus GG can modulate the immune-suppressive effect of UVR and skin tumour development in female Crl:SKH-1-hrBR mice. For this purpose, two irradiation models were studied: (1) a chronic irradiation scheme consisting of daily irradiations during twenty consecutive days and (2) a long-term irradiation schedule, irradiating the animals three times per week, during 34 weeks for tumour development. The results showed that T-cells in the inguinal lymph node of LTA-treated mice produced higher levels of (1) interferon-γ and (2) a number of total, helper and cytotoxic T-cells compared with non-treated mice. Moreover, a significant delay in tumour appearance was found in LTA-treated mice. An increased IgA⁺ cell number was found in the small intestine together with a higher number of activated dendritic cells in the mesenteric lymph nodes. The latter results might be indicative of a direct effect of LTA in the gut, affecting the cutaneous immune system and restoring homeostasis through the gut-skin axis.

Lipoteichoic acid of Bifidobacterium in combination with 5-fluorouracil inhibit tumor growth and relieve the immunosuppression.

UNLABELLED: To investigate the therapeutic efficacy of lipoteichoic acid of Bifidobacterium (BLTA) in combination with 5-fluorouracil (5-FU) treatment on the mice bearing inoculated hepatoma-22 (H(22)) cells and the effects of BLTA on immunological regulation of organism, and explore its mechanisms. METHODS: Tumor-bearing mice were treated with 5-FU alone, BLTA alone or BLTA in combination with 5-FU. The tumor size were observed and measured regularly. The growth inhibiting rate (IR) of tumor was detected. MTT assay was used to evaluate the proliferation of T lymphocytes and splenic NK cell and CTL activity. Enzyme linked immunosorbent assay (ELISA) was used to detect the change of IFN-γ. FCM was used to detect T subgroup ratio of spleen cells of tumor-bearing mice. Expression change of mRNA and proteins of Foxp3 and TIM-3 were detected by Real-Time-PCR and Western blot in tumor-bearing mice tumor tissue. RESULTS: Both 5-FU and BLTA had inhibition effect on tumor-growth. While in the 5-FU + BLTA group, the inhibition of tumor growth was more significant, with increased T lymphocyte proliferation and IFN-γproduction of spleen cells. Spleen cells of tumor-bearing mice had high CD4(+)CD25(+)regulatory T cell (CD4(+)CD25(+)T(reg)) ratio and high mRNA and proteins expression of Foxp3 and TIM-3, but in the BLTA and 5-FU group, CD4(+)CD25(+)T(reg) ratio degraded, with down regulation mRNA and proteins expression of Foxp3 and TIM-3. But CD4(+) T cells also decreased in spleen cells of tumor-bearing mice by alone 5-FU treated, splenic NK cell and CTL activity also degraded, while CD4(+) T cells and splenic NK cell and CTL activity significantly increased by BLTA treated. BLTA in combination with 5-FU could also enhance the ratio of CD4(+) T cells and splenic NK cell and CTL activity. CONCLUSION: The present study suggested that BLTA in combination with 5-FU could enhance antitumor effect, with inhibiting TIM-3/TIM-3L pathway, cutting down immunosuppressive activity of CD4(+)CD25(+) T(reg) and enhancing cell-mediated immunity.

Lipoteichoic acid induces delayed myocardial protection in isolated rat hearts: a comparison with endotoxin.

OBJECTIVE: Preconditioning with bacterial wall fragments lipopolysaccharide (LPS) or lipoteichoic acid (LTA) reduce myocardial infarct size after ischaemia and reperfusion (I/R) in rats. Preconditioning with LTA reduces neutrophil accumulation during reperfusion and thereby ameliorates one of myocardial reperfusion injury's most important mechanisms. In this study, we use an ex vivo model of regional myocardial I/R to investigate LTA versus LPS induced preconditioning in a system devoid of leukocytes. METHODS: Rats were subjected to LTA or LPS with or without dexamethasone pre-treatment. Twenty-four hours after LTA or LPS challenge, hearts were removed and retrogradely perfused in a Langendorff set-up. Hearts underwent 20 min of regional ischaemia followed by 2 h of reperfusion. Ischaemic preconditioning (IPC) was performed as a positive control. Myocardial infarct size was determined as the primary end-point. RESULTS: LTA and LPS preconditioning both lead to a marked reduction in infarct size similar to IPC, however, no significant differences were found between LTA and LPS. The reduction in infarct size was abrogated by dexamethasone pre-treatment. CONCLUSION: We conclude that preconditioning with LTA and likewise with LPS confers myocardial protection in an ex vivo setting devoid of leukocytes. Dexamethasone inhibits preconditioning, suggesting that the underlying mechanism is dependent upon induction of a systemic inflammatory response to a LTA or LPS stimulus.

An antimicrobial peptide modulates epithelial responses to bacterial products.

INTRODUCTION: Changes in the respiratory epithelium and chronic and recurrent infections are thought to play a central role in the pathogenesis of otitis media and sinusitis. The airway epithelium is the primary defense system of the respiratory tract. Bacterial cell membrane components like lipopolysaccharide (LPS) and lipoteichoic acid (LTA) can affect the mucociliary clearance function of the respiratory epithelium. P60.4-Ac is a synthetic antimicrobial peptide based on the structure of the cathelicidin LL-37 that neutralizes the pro-inflammatory activity of LPS and LTA. MATERIALS AND METHODS: Normal respiratory sinus epithelium was cultured at the air liquid interface. The cells were incubated with LPS or LTA in the presence or absence of P60.4-Ac. RESULTS: P60.4-Ac neutralized the LPS- and LTA- induced effect on air-liquid interface cultured epithelial cells. P60.4-Ac significantly inhibited the increase in the epithelial layer caused by LPS or LTA. CONCLUSION: These data demonstrate that P60.4-Ac might be of clinical benefit in the management of otitis media with effusion and sinusitis.

Enhanced antiinflammatory capacity of a Lactobacillus plantarum mutant synthesizing modified teichoic acids.

Teichoic acids (TAs), and especially lipoteichoic acids (LTAs), are one of the main immunostimulatory components of pathogenic Gram-positive bacteria. Their contribution to the immunomodulatory properties of commensal bacteria and especially of lactic acid bacteria has not yet been investigated in detail. To evaluate the role of TAs in the interaction between lactic acid bacteria and the immune system, we analyzed the antiinflammatory properties of a mutant of Lactobacillus plantarum NCIMB8826 affected in the TA biosynthesis pathway both in vitro (mononuclear cells stimulation) and in vivo (murine model of colitis). This Dlt- mutant was found to incorporate much less D-Ala in its TAs than the WT strain. This defect significantly impacted the immunomodulation reactions induced by the bacterium, as shown by a dramatically reduced secretion of proinflammatory cytokines by peripheral blood mononuclear cells and monocytes stimulated by the Dlt- mutant as compared with the parental strain. Concomitantly, a significant increase in IL-10 production was stimulated by the Dlt- mutant in comparison with the WT strain. Moreover, the proinflammatory capacity of L. plantarum-purified LTA was found to be Toll-like receptor 2-dependent. Consistent with the in vitro results, the Dlt- mutant was significantly more protective in a murine colitis model than its WT counterpart. The results indicated that composition of LTA within the whole-cell context of L. plantarum can modulate proinflammatory or antiinflammatory immune responses.

Anti-adhesion therapy of bacterial diseases: prospects and problems.

The alarming increase in drug-resistant bacteria makes a search for novel means of fighting bacterial infections imperative. An attractive approach is the use of agents that interfere with the ability of the bacteria to adhere to tissues of the host, since such adhesion is one of the initial stages of the infectious process. The validity of this approach has been unequivocally demonstrated in experiments performed in a wide variety of animals, from mice to monkeys, and recently also in humans. Here we review various approaches to anti-adhesion therapy, including the use of receptor and adhesin analogs, dietary constituents, sublethal concentrations of antibiotics and adhesin-based vaccines. Because anti-adhesive agents are not bactericidal, the propagation and spread of resistant strains is much less likely to occur than as a result of exposure to bactericidal agents, such as antibiotics. Anti-adhesive drugs, once developed, may, therefore, serve as a new means to fight infectious diseases.

Enhancement of anti-cancer immunity by a lipoteichoic-acid-related molecule isolated from a penicillin-killed group A Streptococcus.

We isolated the lipoteichoic-acid-related molecule (OK-PSA) from OK-432, a streptococcal preparation, by affinity chromatography on CNBr-activated Sepharose-4B-bound monoclonal antibody TS-2, which neutralizes the interferon (IFN)-gamma-inducing activity of OK-432. We have previously reported that OK-PSA is a potent inducer of Th1-type cytokines in human peripheral blood mononuclear cells in vitro. In this study, we conducted an animal experiment to examine whether OK-PSA exhibits an anti-tumor effect in vivo by acting as a Th1 inducer in syngeneic Meth-A tumor-bearing BALB/c mice, in which the Th2 response is genetically dominant. It was found that OK-PSA induced Th1-type cytokines [IFN-gamma, tumor necrosis factor-alpha, interleukin (IL)-2, IL-12 and IL-18] in BALB/c mice bearing Meth-A tumor and caused a marked anti-tumor effect. Although it was suggested by an in vitro study. using spleen cells derived from the animals, that IL-18 plays the greatest role in the induction of the Th1-dominant state and tumor cell killing induced by OK-PSA, the in vivo experiments demonstrated that both IL-12 and IL-18 are essential in the anti-tumor effect exhibited by OK-PSA. These findings strongly suggest that OK-PSA is a major effector molecule of OK-432 and may be a useful immunotherapeutic agent, as a potent Th1 inducer, for cancer patients with a Th2-dominant state.

Molecular and structural requirements of a lipoteichoic acid from Enterococcus hirae ATCC 9790 for cytokine-inducing, antitumor, and antigenic activities.

Comparison was made between the immunobiological and antigenic properties of two lipoteichoic acid (LTA) fractions (LTA-1 and -2) from Enterococcus hirae ATCC 9790, their glycolipid portions, and synthetic compounds partially mimicking the above bacterial products. The more lipophilic LTA-2 fraction was capable of inducing serum tumor necrosis factor alpha and interleukin-6 in muramyldipeptide-primed mice and serum gamma interferon in those primed with Propionibacterium acnes. The LTA-2 fraction also induced tumor necrosis factor alpha, interleukin-6, and thymocyte-activating factor (essentially interleukin-1) in murine peritoneal macrophage cultures. Consecutive intravenous injections of muramyldipeptide and the LTA-2 fraction in Meth A fibrosarcoma-bearing BALB/c mice caused hemorrhagic necrosis and marked regression leading to complete regression of the tumor with no accompanying weakening or lethal effects. The LTA-2 fraction was at least 10,000-fold less pyrogenic in rabbits than a reference endotoxic lipopolysaccharide. The more hydrophilic LTA-1 fraction, on the other hand, showed at most marginal activity in the in vivo and in vitro assays. Natural glycolipids (NGL-1 and -2) which were prepared from a chloroform-methanol extract of Streptococcus pyogenes and E. hirae cells, and comparable in structure to the lipid moieties of the LTA-1 and -2 fractions, respectively, were practically inactive in all of the assays. None of the test synthetic compounds was immunobiologically active, although synthetic partial counterparts of the structure of LTA proposed by W. Fischer (Handb. Lipid Res. 6:123-234, 1990) reacted with murine monoclonal antibody TS-2, which was raised against OK-432, a penicillin-killed S. pyogenes preparation, and capable of neutralizing the cytokine-inducing activities of the LTA-2 fraction.

Prevention of group B streptococcal colonization and bacteremia in neonatal mice with topical vaginal inhibitors.

Pregnant Swiss-Webster mice were vaginally inoculated with 10(5) virulent and avirulent serotype III Streptococcus agalactiae and treated 4 days later with topical vaginal inhibitor solutions. Preparations containing lipoteichoic acid (LTA) or glycerophosphate (GP), the repeating linear backbone of LTA, significantly reduced neonatal colonization and bacteremia by the virulent isolate and colonization by the avirulent strain. Similar results were obtained if bacteria were preincubated with LTA or GP at 37 degrees C for 30 min before vaginal inoculation. Human serum albumin (HSA), a known inhibitor of binding of LTA to human fetal epithelial cells, also resulted in reduction in colonization and bacteremia of neonatal mice. However, maternal treatment with a combination of HSA (2%) and GP (1%) completely prevented neonatal colonization and bacteremia without altering the normal aerobic bacterial vaginal flora. These results provide impetus to the development of an alternative means of preventing neonatal group B streptococcal infections in humans without requiring maternal immunization or chemoprophylaxis.

Immunostimulating staphylococcal lipoteichoic acid prevents pulmonary tumor colonization in BALB/c-mice.

Immunostimulating and antineoplastic activities of staphylococcal lipoteichoic acid (LTA) were studied in Balb/c-mice. Systemic administration of LTA (1 mg or 2 mg i. p., 7 and 4 days prior to challenge) significantly enhanced chemiluminescence response of peritoneal macrophages (p less than 0.0125) and induced enlargement of the spleen (p less than 0.025) as compared to non-treated controls. In vivo the number of lung colonies was significantly lower (p less than 0.0125) in LTA-treated mice 14 days after challenge with L-1 sarcoma cells.

Antitumour effects of streptococcal lipoteichoic acids on Meth A fibrosarcoma.

The antitumour effects of lipoteichoic acids (LTA) extracted from Streptococcus pyogenes were studied in comparison with other streptococcal cellular components. LTA suppressed the tumour growth of both solid- and ascites-type Meth A fibrosarcoma as did the whole cells of S. pyogenes (OK-432). No other cellular components, such as cell wall peptidoglycan, group-specific C-carbohydrate or type-specific M protein, suppressed the growth of Meth A. LTA, but not the other cellular components, induced tumour necrosis factor (TNF) in Propionibacterium acnes-primed mice. LTA had no direct killing effects on Meth A cells. These results indicate that LTA may be an important antitumour component of OK-432 and that one of the antitumour mechanisms by this streptococcal preparation is the induction of TNF.

[Structure of teichoic acid of a poly(glycerophosphate) nature from Streptomyces levoris K-3053 and its biological properties]. / Struktura teikhoevoi kisloty poli(glitserofosfatnoi) prirody Streptomyces levoris K-3053 i nekotorye ee biologicheskie svoistva.

The wall teichoic acid from S. levoris was studied. It is a poly(glycerophosphate)polymer consisting of 15-20 nonsubstituted glycerophosphate units coupled by the phosphodiether bonds according to the 1, 3 type. It was shown that the acid had antitumor activity and high cardiotoxicity evident from a clear-cut negative ionotropic effect on the cardiac papillar muscle in dogs.

Prevention of group B streptococcal colonization with topically applied lipoteichoic acid in a maternal-newborn mouse model.

An animal model of maternal-newborn transmission of group B streptococci (GBS) was developed. Pregnant Swiss-Webster mice were colonized by applying 10(8) GBS to the oral cavity, vagina, and nipples daily for 3 days before delivery. Lipoteichoic acid (LTA) from type III GBS or phosphate buffered saline was applied topically to the oral cavity, perineum or nape of newborn mice. Cultures of newborn mice at 3 days of age revealed 35 of 75 (47%) controls and 0 of 79 animals given 2 doses of LTA (2 mg/ml) were positive for GBS at one or more sites. One to two% of control and LTA-treated mice remained culture positive at 7 days of age. None developed GBS disease and no obvious toxicity was noted. This is the first in vivo evidence that colonization with GBS can be prevented by interfering with their adherence to epithelial surfaces. LTA also prevented colonization by 60,000 GBS in the oral cavity of 1-day-old newborn mice. A minimum concentration of 0.5 mg LTA/ml was required and similar dose response curves were obtained in preventing maternal-newborn transmission or oral newborn colonization. LTA from type III GBS also protected against types Ia and II. Only 6 of 15 (40%) vaginally colonized, nonpregnant mice became noncolonized 3 days after LTA treatment. Topically applied lipoteichoic acid from group B streptococci may be a useful method of preventing GBS colonization and/or disease in human infants at birth if it is nontoxic. The method avoids the problems associated with antibiotic prophylaxis and vaccine development.