Preparation and immune-enhancing effects of monophosphoryl lipid A pH-sensitive liposome / 中华微生物学和免疫学杂志

Objective:To prepare pH-sensitive liposomes to avoid the degradation of monophosphoryl lipid A (MPLA) by lysosomes.Methods:Using DOPE and CHEMS as carrier materials, pH-sensitive liposomes were prepared by thin-film dispersion method. Particle sizes and Zeta potential of the liposomes were detected by dynamic light scattering. The morphological features of pH-sensitive liposomes under different pH conditions were observed by transmission electron microscopy. Flow cytometry was performed to detect the phagocytosis of liposomes by THP-1 and DC2.4 cells. Confocal laser microscopy was used to observed the colocalization of liposomes and lysosomes. BALB/c mice were immunized with hepatitis B surface antigen (HBsAg) using MPLA pH-sensitive liposome as an adjuvant. The levels of serum anti-HBs were quantitatively detected by ELISA. IFN-γ and IL-2 spot forming cells (SFCs) in mouse splenic lymphocytes were detected by ELISPOT.Results:The pH-sensitive liposomes were constructed with an average particle size of (90.90±1.13) nm, polydispersity index (PDI) of 0.076±0.013 and Zeta potential of (-27.900±0.666) mV. As the pH value of the solution decreased, the particle size increased significantly and the liposomes presented irregular shapes, indicating the pH-sensitive features. The phagocytosis rates by THP-1 cells and DC2.4 cells were 10.40% and 12.40% for pH-sensitive fluorescent liposomes, and 1.09% and 0.28% for fluorescent liposomes. Confocal laser microscopy revealed that pH-sensitive fluorescent liposomes were phagocytosed by THP-1 cells and existed in the cytoplasm, while fluorescent liposomes existed in lysosomes. Compared with MPLA liposomes, MPLA pH-sensitive liposomes could significantly improve the cellular immune response in mice. The levels of IFN-γ and IL-2 SFCs in the MPLA pH-sensitive liposome group were significantly higher than those in the MPLA liposome group ( P<0.01) and the non-adjuvant group ( P<0.001). Conclusions:The pH-sensitive liposome delivery system could improve the utilization of MPLA as an adjuvant.

Lipid profile, functional capacity and ankle-brachial index in active older adults / Perfil lipídico, capacidade funcional e índice tornozelo-braquial em idosos ativos / Perfil lipídico, capacidad funcional e índice tobillo-braquial en adultos de la tercera edad activos

ABSTRACT Introduction: Regular physical activity prevents cardiovascular diseases (CVD) and atherosclerosis, in addition to improving lipid levels and functional capacity in older adults. Objective: To evaluate and compare the lipid levels, functional performance and ankle brachial index (ABI) of sedentary and active older adults. Methods: This was a comparative cross-sectional study with 84 elderly (≥60 years) male and female subjects, divided into two groups: sedentary group (SG, n = 50) and active group (AG, n = 34) according to the International Physical Activity Questionnaire (IPAQ). Anthropometric and hemodynamic assessments, ankle brachial index (ABI) calculations, and functionality tests (Short Physical Performance Battery - SPPB and 6-minute walking test - 6MWT) were performed. The Shapiro-Wilk normality test was also used, and we conducted the Student's-t and Mann-Whitney tests for the intergroup comparison. For the categorical data, we used Fisher's exact test (p <0.05). Results: Higher values of high-density lipoprotein cholesterol (HDL-c) (p = 0.001) and lower triglycerides (TG) (p = 0.007) were found in AG compared to SG. In the ABI evaluation, AG presented better right (p = 0.012), left (p = 0.015) and end (p = 0.004) ABI rates when compared to SG. AG had better results in functional performance in the SPPB evaluation (p = 0.0007) and in the 6MWT with a greater distance covered (p = 0.0027). In the anthropometric measurements, AG had lower body mass index (BMI) (0.041) and a smaller abdominal circumference (WC) (0.029). In terms of the incidence of referred diseases, intergroup results were only different for hypertension (0.029), while AG had a lower incidence of hypertension. Conclusion: Active older adults had better lipid levels, higher ABI levels, better functional performance, lower body mass, a smaller abdominal circumference, and lower incidence of hypertension, in comparison to sedentary subjects. Level of evidence I; High quality prospective study.

RESUMO Introdução: A prática de atividade física regular previne doenças cardiovasculares (DCV) e aterosclerose, além de melhorar o perfil lipídico e a capacidade funcional em idosos. Objetivo: Avaliar e comparar o perfil lipídico, desempenho funcional e índice tornozelo-braquial (ITB) de idosos sedentários e ativos. Métodos: Trata-se de um estudo comparativo e transversal com 84 idosos (≥ 60 anos) de ambos os sexos, divididos em dois grupos: grupo sedentário (GS, n= 50) e grupo ativo (GA, n= 34) segundo o Questionário Internacional de Atividade Física (IPAQ). Foram realizadas avaliações antropométricas, hemodinâmicas, índice tornozelo-braquial (ITB) e testes de funcionalidade (Short Physical Performance Battery - SPPB e teste de caminhada de 6 minutos - TC6). Além disso, foi utilizado o teste de normalidade Shapiro-Wilk e na comparação entre os grupos utilizou-se o teste t-Student e o teste Mann-Whitney. Já para os dados categóricos, utilizou-se o teste exato de Fisher (p<0,05). Resultados: Foi verificado no GA valores maiores da lipoproteína de alta densidade (high-density lipoprotein cholesterol, HDL-c) (p = 0,001) e menores de triglicerídeo (TG) (p = 0,007) quando comparados ao GS. Na avaliação ITB, observou-se que o GA apresentou melhores índices de ITB direito (p = 0,012), esquerdo (p = 0,015) e final (p = 0,004) quando comparado ao GS. Houve melhores resultados do GA no desempenho funcional na avaliação SPPB (p = 0,0007) e no TC6 com maior distância percorrida (p = 0,0027). Nas medidas antropométricas, o GA apresentou menor índice de massa corporal (IMC) (0,041) e circunferência abdominal (CA) (0,029). Na incidência das doenças referidas, apenas a hipertensão apresentou resultados diferentes entre os grupos (0,029), sendo que o GA teve menor incidência de hipertensão. Conclusão: Os idosos ativos apresentaram melhor perfil lipídico, maiores níveis de ITB, melhor desempenho funcional, além de menor massa corpórea, menor circunferência abdominal e menor incidência de hipertensão em comparação aos sedentários. Nível de evidência I; Estudo prospectivo de alta qualidade.

RESUMEN Introducción: La práctica de actividad física regular previene enfermedades cardiovasculares (ECV) y aterosclerosis, además de mejorar el perfil lipídico y la capacidad funcional en adultos de la tercera edad. Objetivo: Evaluar y comparar el perfil lipídico, desempeño funcional e índice tobillo-braquial (ITB) en adultos de la tercera edad sedentarios y activos. Métodos: Se trata de un estudio comparativo y transversal, con 84 adultos de la tercera edad (≥ 60 años) de ambos sexos, divididos en dos grupos: grupo sedentario (GS, n = 50) y grupo activo (GA, n = 34) según el Cuestionario Internacional de Actividad Física (IPAQ). Fueron realizadas evaluaciones antropométricas, hemodinámicas, índice tobillo-braquial (ITB) y tests de funcionalidad (Short Physical Performance Battery - SPPB y Test de Caminata de 6 minutos - TC6). Además, se utilizó el test de normalidad Shapiro-Wilk y en la comparación entre los grupos se usó el test t-Student y el test Mann-Whitney. Ya para los datos categóricos se usó el test exacto de Fisher (p <0,05). Resultados: Se verificaron en el GA valores mayores de lipoproteína de alta densidad (high-density lipoprotein cholesterol, HDL-c) (p = 0,001) y menores de triglicéridos (TG) (p = 0,007) cuando comparados al GS. En la evaluación ITB, se observó que el GA mostró mejores índices de ITB derecho (p = 0,012), izquierdo (p = 0,015) y final (p = 0,004) cuando comparado al GS. Hubo mejores resultados del GA en el desempeño funcional en la evaluación SPPB (p = 0,0007) y en el TC6 con mayor distancia recorrida (p = 0,0027). En las medidas antropométricas, el GA presentó menor índice de masa corporal (IMC) (0,041) y circunferencia abdominal (CA) (0.029). En la incidencia de las enfermedades referidas, sólo la hipertensión presentó resultados diferentes entre los grupos (0.029), siendo que el GA tuvo menor incidencia de hipertensión. Conclusión: Los adultos de la tercera edad activos presentaron mejor perfil lipídico, mayores niveles de ITB, mejor desempeño funcional, además de menor masa corpórea, menor circunferencia abdominal y menor incidencia de hipertensión en comparación a los sedentarios. Nivel de evidencia I; Estudio prospectivo de alta calidad.

Avaliação prospectiva das repercussões no perfil lipídico das cirurgias que envolvem lipoaspiração e dermolipectomias / Prospective assessment of the repercussions on the lipid profile of surgeries involving liposuction and dermolipectomies

Introdução: Lipoaspiração associada a dermolipectomias é o procedimento cirúrgico mais comumente realizado em cirurgia plástica. Apesar de ser considerada uma cirurgia extremamente segura, algumas considerações devem ser levantadas a respeito dos possíveis efeitos metabólicos que essas cirurgias possam causar. O desenvolvimento da técnica tumescente de lipoaspiração permitiu a remoção de grande quantidade de gordura de modo mais seguro. O objetivo é comparar as variações do perfil lipídico em pós-operatório precoce e tardio de pacientes submetidos à lipoaspiração e dermolipectomias. Métodos: Entre outubro de 2006 e junho de 2012, 40 pacientes do sexo feminino candidatas a cirurgias que envolviam lipoaspiração e dermolipectomias foram acompanhadas prospectivamente e o perfil lipídico foi analisado por meio de exames no pré-operatório e no pós-operatório. As cirurgias realizadas foram: mamoplastia + lipoaspiração, abdominoplastia + lipoaspiração e lipoabdominoplastia + mamoplastia. Resultados: Das 40 pacientes que foram acompanhadas no estudo, 20 pacientes do sexo feminino foram selecionadas (após a aplicação dos critérios de exclusão). Em consonância com nosso estudo, Cazes, em 1996, demonstrou que após 12 meses de pós-operatório de lipoabdominoplastia não houve alteração do perfil lipídico das pacientes. Conclusão: Após análise pré- e pós-operatória de 20 pacientes, observamos que não há alterações estatísticas significantes em relação ao perfil lipídico com tendência de equilíbrio das aferições em um ano em patamares próximos aos observados no pré-operatório.

Introduction: Liposuction associated with dermolipectomies is the most commonly performed surgical procedure in plastic surgery. Although regarded as an extremely safe surgery, some considerations must be taken on the possible metabolic effects of these surgeries. The development of the tumescent technique in liposuction allowed the safer removal of large amounts of fat. The objective is to compare lipid profile variations in the early and late postoperative period in patients undergoing liposuction and dermolipectomies. Methods: Between October 2006 and June 2012, 40 female patients who were candidates for surgeries involving liposuction and dermolipectomies were prospectively followed, and the lipid profile was analyzed through preoperative and postoperative examinations. The surgeries performed were mammoplasty + liposuction, abdominoplasty + liposuction, and lipoabdominoplasty + mammoplasty. Results: Of the 40 female patients who were followed, 20 were selected (after applying the exclusion criteria). In agreement with our study, in 1996, Cazes showed that there were no changes in the lipid profile of patients 12 months after lipoabdominoplasty. Conclusion: After a preoperative and postoperative analysis of 20 patients, it was observed that there were no statistically significant changes in the lipid profile and that the measurements after 1 year were close to those obtained in the preoperative period.

Differences in Colistin-resistant Acinetobacter baumannii Clinical Isolates Between Patients With and Without Prior Colistin Treatment

BACKGROUND: The increasing morbidity and mortality rates associated with Acinetobacter baumannii are due to the emergence of drug resistance and the limited treatment options. We compared characteristics of colistin-resistant Acinetobacter baumannii (CR-AB) clinical isolates recovered from patients with and without prior colistin treatment. We assessed whether prior colistin treatment affects the resistance mechanism of CR-AB isolates, mortality rates, and clinical characteristics. Additionally, a proper method for identifying CR-AB was determined. METHODS: We collected 36 non-duplicate CR-AB clinical isolates resistant to colistin. Antimicrobial susceptibility testing, Sanger sequencing analysis, molecular typing, lipid A structure analysis, and in vitro synergy testing were performed. Eleven colistin-susceptible AB isolates were used as controls. RESULTS: Despite no differences in clinical characteristics between patients with and without prior colistin treatment, resistance-causing genetic mutations were more frequent in isolates from colistin-treated patients. Distinct mutations were overlooked via the Sanger sequencing method, perhaps because of a masking effect by the colistin-susceptible AB subpopulation of CR-AB isolates lacking genetic mutations. However, modified lipid A analysis revealed colistin resistance peaks, despite the population heterogeneity, and peak levels were significantly different between the groups. CONCLUSIONS: Although prior colistin use did not induce clinical or susceptibility differences, we demonstrated that identification of CR-AB by sequencing is insufficient. We propose that population heterogeneity has a masking effect, especially in colistin non-treated patients; therefore, accurate testing methods reflecting physiological alterations of the bacteria, such as phosphoethanolamine-modified lipid A identification by matrix-assisted laser desorption ionization-time of flight, should be employed.

Distinct Effects of Monophosphoryl Lipid A, Oligodeoxynucleotide CpG, and Combination Adjuvants on Modulating Innate and Adaptive Immune Responses to Influenza Vaccination

Monophosphoryl lipid A (MPL) and oligodeoxynucleotide CpG are toll-like receptor (TLR) 4 and 9 agonist, respectively. Here, we investigated the effects of MPL, CpG, and combination adjuvants on stimulating in vitro dendritic cells (DCs), in vivo innate and adaptive immune responses, and protective efficacy of influenza vaccination. Combination of MPL and CpG was found to exhibit distinct effects on stimulating DCs in vitro to secrete IL-12p70 and tumor necrosis factor (TNF)-α and proliferate allogeneic CD8 T cells. Prime immunization of mice with inactivated split influenza vaccine in the presence of low dose MPL+CpG adjuvants increased the induction of virus-specific IgG and IgG2a isotype antibodies. MPL and CpG adjuvants contribute to improving the efficacy of prime influenza vaccination against lethal influenza challenge as determined by body weight monitoring, lung function, viral titers, and histology. A combination of MPL and CpG adjuvants was effective in improving vaccine efficacy as well as in reducing inflammatory immune responses locally and in inducing cellular immune responses upon lethal influenza virus challenge. This study demonstrates unique adjuvant effects of MPL, CpG, and combination adjuvants on modulating innate and adaptive immune responses to influenza prime vaccination.

Lipid A as a Drug Target and Therapeutic Molecule

In this review, lipid A, from its discovery to recent findings, is presented as a drug target and therapeutic molecule. First, the biosynthetic pathway for lipid A, the Raetz pathway, serves as a good drug target for antibiotic development. Several assay methods used to screen for inhibitors of lipid A synthesis will be presented, and some of the promising lead compounds will be described. Second, utilization of lipid A biosynthetic pathways by various bacterial species can generate modified lipid A molecules with therapeutic value.

In Vivo Selection of Pan-Drug Resistant Acinetobacter baumannii during Antibiotic Treatment

PURPOSE: Colistin resistance in Acinetobacter baumannii (A. baumannii) is mediated by a complete loss of lipopolysaccharide production via mutations in lpxA, lpxC, and lpxD gene or lipid A modifications via mutations in the pmrA and pmrB genes. However, the exact mechanism of therapy-induced colistin resistance in A. baumannii is not well understood. MATERIALS AND METHODS: We investigated the genotypic and phenotypic changes that underlie pan-drug resistance mechanisms by determining differences between the alterations in extensively drug-resistant (XDR) A. baumannii (AB001 and AB002) isolates and a pan-drug resistant (PDR) counterpart (AB003) recovered from one patient before and after antibiotic treatment, respectively. RESULTS: All three clinical isolates shared an identical sequence type (ST138), belonging to the global epidemic clone, clonal complex 92, and all produced OXA-23 carbapenemase. The PDR AB003 showed two genetic differences, acquisition of armA gene and an amino acid substitution (Glu229Asp) in pmrB gene, relative to XDR isolates. No mutations were detected in the pmrA, pmrC, lpxA, lpxC, or lpxD genes in all three isolates. In matrix-assisted laser desorption ionization-time of flight analysis, the three isolates commonly showed two major peaks at 1728 m/z and 1912 m/z, but peaks at 2034 m/z, 2157 m/z, 2261 m/z, and 2384 m/z were detected only in the PDR A. baumannii AB003 isolate. CONCLUSION: Our results show that changes in lipid A structure via a mutation in the pmrB gene and acquisition of armA gene might confer resistance to colistin and aminoglycosides to XDR A. baumannii strains, resulting in appearance of a PDR A. baumannii strain of ST138.

Porphyromonas gingivalis resistance to polymyxin B is determined by the lipid A 4'-phosphatase, PGN_0524 / 国际口腔科学杂志·英文版

<p><b>AIM</b>To elucidate the genetic basis for the pronounced resistance that the oral pathogen, Porphyromonas gingivalis (P. gingivalis), exhibits towards the cationic antimicrobial peptide, polymyxin B.</p><p><b>METHODOLOGY</b>A genetic screen of P. gingivalis clones generated by a Tn4400'-based random insertion mutagenesis strategy was performed to identify bacteria harboring novel genetic mutations that render P. gingivalis susceptible to killing by the cationic antimicrobial peptide, polymyxin B (PMB, 50 microg x mL(-1)).</p><p><b>RESULTS</b>P. gingivalis (ATCC 33277) is unusually resistant to the cationic antimicrobial peptide, PMB at relatively high concentrations (200 microg x mL(-1)). Approximately 2,700 independent Tn4400'-derived mutants of P. gingivalis were examined for increased sensitivity to PMB killing at a relatively low dose (50 microg x mL(-1)). A single PMB-sensitive mutant was obtained in this phenotypic screen. We determined that the Tn4400' transposon was integrated into the gene encoding the lipid A 4'-phosphatase, PGN_0524, demonstrating that this insertion event was responsible for its increased susceptibility of this clone to PMB-dependent killing. The resulting mutant strain, designated 0524-Tn4400', was highly sensitive to PMB killing relative to wild-type P. gingivalis, and exhibited the same sensitivity as the previously characterized strain, 0524KO, which bears a genetically engineered deletion in the PGN_0524 locus. Positive ion mass spectrometric structural (MALDI-TOF MS) analyses revealed that lipid A isolates from 0524-Tn4400' and 0524KO strains displayed strikingly similar MALDI-TOF MS spectra that were substantially different from the wildtype P. gingivalis lipid A spectrum. Finally, intact 0524-Tn4400' and 0524KO mutant bacteria, as well as their corresponding LPS isolates, were significantly more potent in stimulating Toll-like receptor 4 (TLR4)-dependent E-selectin expression in human endothelial cells relative to intact wild-type P. gingivalis or its corresponding LPS isolate.</p><p><b>CONCLUSION</b>The combined molecular evidence provided in this report suggests that PGN_0524, a lipid A 4'-phosphatase, is the sole genetic element conferring the ability of the periodontopathogen, P. gingivalis, to evade the killing activity of cationic antimicrobial peptides, such as PMB. These data strongly implicate PGN_0524 as a critical virulence factor for the ability of P. gingivalis to evade front-line host innate defenses that are dependent upon cationic antimicrobial peptide activity and TLR 4 sensing.</p>

The cytokine-inducing activities of surface components of the periodontopathogenic bacterium Porphyromonas gingivalis / 대한치주과학회지

This study was carried out to examine the potency of the three surface components from Porphyromonas gingivalis to stimulate the murine macrophage cell line RAW264.7 to synthesize the pro-inflammatory cytokine tumor necrosis factor alpha(TNF-alpha) and nitric oxide (NO). Lipopolysaccharide(LPS), lipid A-associated proteins(LAP) and saline-extractable surface -associated material(SAM) were isolated from P. gingivalis 381. TNF-alpha release into culture supernatants was determined by two-site ELISA. NO production was assayed by measuring the accumulation of nitrite in culture supernatants. Western blot analysis of iNOS and analysis of reverse transcription(RT)-PCR products were carried out. The surface components extracted from this bacterium were almost equally potent in stimulating release of TNF-alpha and NO by RAW264.7 cells. TNF-alpha that was being measured immunologically was due to activation of TNF-alpha gene transcription. The present study clearly shows that P. gingivalis surface components fully induced iNOS expression in RAW264.7 cells in the absence of other stimuli. The ability of P. gingivalis surface components to promote the production of TNF-alpha and NO may be important in the pathogenesis of inflammatory periodontal disease.

Extracellular signal regulatory kinases mediate the cardioprotection induced by monophosphoryl lipid A / 中国病理生理杂志

AIM: To investigate the cardioprotective effects of monophosphoryl lipid A(MLA) and its molecular mechanisms.METHODS: In the ischemia/reperfusion(I/R) model of porcine hearts, the effect of MLA on myocardial infarct size was observed. The protein levels of extracellular signal regulatory kinases (ERKs) and heat shock protein (HSP) 86 were detected by using western blotting method. RESULTS: MLA pretreatment significantly limited the infarct size in the porcine hearts subjected to I/R. It is also found that MLA pretreatment upregulated the protein levels of HSP86 and ERKs. CONCLUSION: MLA pretreatment can attenuate I/R injury in porcine hearts. The protective mechanism might be associated with ERKs-induced upregulation of HSP86 synthesis.

Monophosphoryl lipid A (MPL) upregulates major histocompatibility complex (MHC) class I expression by increasing interferon-gamma (IFN-gamma)

Tumor immunity is primarily mediated by cells as CD8+ cytotoxic T lymphocytes (CTL) recognize tumor antigen by MHC class I molecules. But most tumors are associated with a decreased expression of MHC class I to escape the antitumor immunity of the host. Our previous data have demonstrated that MPL has an antitumor effect on metastatic lung cancer of B16 melanoma with enhancing cytotoxicity due to increase of IFN-gamma and IL-2, and decrease of IL-4, which indicates the stimulation of type 1 helper T cells (Th1). To determine the effects of MPL, IFN-gamma, TNF-alpha, and IL-1 alpha on MHC class I expression of B16 melanoma cells, we evaluated the expression of MHC class I molecules with treatments of MPL, IFN-gamma, TNF-alpha, and IL-1 alpha by flow cytometry. The supernatant of MPL-treated spleen cells in vitro upregulated the expression of MHC class I molecules of B16 melanoma cells compared to the control supernatant of spleen cells. The MHC class I expression of B16 melanoma cells treated with IFN-gamma, but not TNF-alpha or IL-1 alpha, increased in a time-dependent manner. In conclusion, MPL upregulated MHC class I expression of B16 melanoma cells by activating spleen cells via IFN-gamma. These data suggest that increased IFN-gamma by MPL is responsible for the upregulation of MHC class I expression to augment cytotoxicity. Therefore, we suggest that MPL could play an important role in immunotherapy.

Study of Isolating Anti-Endotoxin Monomer Component from Radix Paeoniae Rubra Biosensor by Biosensor Technique / 中国药房

OBJECTIVE:To isolate anti-endotoxin monomer component from Radix Paeoniae Rubra by means of biosen?sor technique.METHODS:The surface of biosensor cuvette was embedded by Lipid A;the screening target was established,tracking the silica gel column chromatogram and the binding ability of effluent component from HPLC with Lipid A with the ultraviolet scan result of the reclaimed material from biosensor as reference;anti-endotoxin monomer component was isolated;the component of monomer and the synthetic action of extrinsic lipopolysaccharides were also assayed by LAL test method.RESULTS:Components binding to Lipid A was reclaimed from cuvetee by biosensor technique,with the wavelength of UV absorption peak at194nm,215nm and275nm respectively.Anti-endotoxin monomers of higher binding activity with Lipid A isolated by HPLC method were1,2,3,4,6—O—pentagalloyl—?—D—glucose(PGG).PGG at concentration of8,4,2?g/ml respectively neutralized68.8%,43.7%and31.4%of LPS at an activity of0.1EU/ml respectively.CONCLUSION:It is fea?sible to isolate anti-endotoxin monomer component from Radix Paeoniae Rubra by means of biosensor technique,which is a fast,accurate and efficient and can be used to isolate anti-endotoxin monomer component from Radix Paeoniae Rubra on a large scale.

STRUCTURAL PROPERTIES OF THE LIPID A COMPONENT OF THE LIPOPOLYSACCHARIDE (ENDOTOXIN) ISOLATED FROM BACTERIODES FRAGILIS NCTC 9343 / 第二军医大学学报

Various chemical and gas-liquid chromatographic analyses indicate that the lipid A backbone of the lipopolysaccharide (LPS) isolated from Bacteriodes fragilis NCTC 9343 is chemically constituted by a ?1, 6-interlinked D-gluco-samine disaccharide. It is phosphorylated at its 1-position by a glycosidic-linkage while the ester-bound phosphate present generally in other lipid A is depleted. The lipid A is lower fatty acylated in the amount of 5.2 fatty acids per lipid A molecule (of which 0.73 forms 3-acyloxyacyl groups). The LPS containing such a lipid A component has been shown endowing with a weaker endotoxicity.

PREPARATION AND STRUCTURAL CHARACTERIZATION OF THE LIPID A COMPONENT OF SALMONELLA TYPHIMURIUM SL1102 RE-LIPOPOLYSACCHARIDE / 第二军医大学学报

The lipid A component of Re-lipopolysaccharide from S.typhimurium SL 1102 was prepared by hydrolysis with a 0.1 mol/L acetate buffer.Chemical as well as advanced l3C-,and 31P-NMR investigations revealed a ?1' ,6-interlinked D-glucosamine diasaccharide, which is substituted by two phosphate(P)groups, one being esterlinked to the non-reducing residue,and another bound glycosidically to the C1 of the reducing residue, is as the central backbone.Its structure is shown as follows:-P-GlcN(?1', 6)GlcN-P-The amino(2 and 2')and hydroxy(3 and 3')groups of the backone are substituted by 3-OH-14: 0, and unhydroxy fatty acids appear to be the subtituents of the hydroxy group of 3-OH-14 :0, in the means of formation of 3-acyloxyacyl ester and amides.