Effects of Hypertonic Saline and Hydroxyethyl Starch on Myeloid-Derived Suppressor Cells in Hemorrhagic Shock Mice under Secondary Bacterial Attack.

OBJECTIVES: The primary target is to reveal whether the resuscitation with hypertonic saline (HTS) or hydroxyethyl starch (HES) would have different effects on the myeloid-derived suppressor cell (MDSC) count and monocytic MDSC (M-MDSC)/granulocytic/neutrophilic MDSC (G-MDSC) rate in the peripheral blood, spleen, and bone marrow nucleated cells (BMNC) in a controlled hemorrhagic shock mouse model under secondary Escherichia coli bacterial infection attack, comparing to resuscitation with normal saline (NS) in 72 hours. METHOD: After hemorrhagic shock with bacteremia, which is induced by Escherichia coli bacterial infection attack, comparing to resuscitation with normal saline (NS) in 72 hours. Method. After hemorrhagic shock with bacteremia, which is induced by Escherichia coli 35218 injection, the mice were distributed into control, NS, HTS, and HES groups. The peripheral blood nucleated cells (PBNC), spleen single-cell suspension, and bone marrow nucleated cells were collected. The flow cytometry was used to detect the MDSC, M-MDSC, and G-MDSC. RESULT: In PBNC, after resuscitation with NS, the MDSC was continuously higher, while the rate of M-MDSC/G-MDSC were continuously lower (P < 0.05). In HTS, the MDSC varied, higher at 24 and 72 hours (P < 0.05). In HTS, the MDSC varied, higher at 24 and 72 hours (P < 0.05). In HTS, the MDSC varied, higher at 24 and 72 hours (P < 0.05). In HTS, the MDSC varied, higher at 24 and 72 hours (P < 0.05). In HTS, the MDSC varied, higher at 24 and 72 hours (P < 0.05), the M-MDSC/G-MDSC were continuously lower (P < 0.05). In the spleen, resuscitation with HTS, the M-MDSC/G-MDSC were continuously lower (P < 0.05). In BMNC, after resuscitation with HES, the M-MDSC/G-MDSC were lower at 24 and 72 hours (P < 0.05). CONCLUSION: In mouse hemorrhagic shock model with bacterial infection, the resuscitation with NS, HTS, or HES induced difference changes in MDSC and M-MDSC/G-MDSC, which were time-dependent and organ-specific. Resuscitation with crystalloid, like NS or HTS, showed longer effects on the MDSC and M-MDSC/G-MDSC in peripheral blood; while HTS has a longer effect on M-MDSC/G-MDSC in the spleen, HES has a stronger impact on the differentiation regulation of MDSC to G-MDSC in the bone marrow.

Comparative transcriptomic analysis of vascular endothelial cells after hypoxia/re-oxygenation induction based on microarray technology.

OBJECTIVE: To provide comprehensive data to understand mechanisms of vascular endothelial cell (VEC) response to hypoxia/re-oxygenation. METHODS: Human umbilical vein endothelial cells (HUVECs) were employed to construct hypoxia/re-oxygenation-induced VEC transcriptome profiling. Cells incubated under 5% O2, 5% CO2, and 90% N2 for 3 h followed by 95% air and 5% CO2 for 1 h were used in the hypoxia/re-oxygenation group. Those incubated only under 95% air and 5% CO2 were used in the normoxia control group. RESULTS: By using a well-established microarray chip consisting of 58 339 probes, the study identified 372 differentially expressed genes. While part of the genes are known to be VEC hypoxia/re-oxygenation-related, serving as a good control, a large number of genes related to VEC hypoxia/re-oxygenation were identified for the first time. Through bioinformatic analysis of these genes, we identified that multiple pathways were involved in the reaction. Subsequently, we applied real-time polymerase chain reaction (PCR) and western blot techniques to validate the microarray data. It was found that the expression of apoptosis-related proteins, like pleckstrin homology-like domain family A member 1 (PHLDA1), was also consistently up-regulated in the hypoxia/re-oxygenation group. STRING analysis found that significantly differentially expressed genes SLC38A3, SLC5A5, Lnc-SLC36A4-1, and Lnc-PLEKHJ1-1 may have physical or/and functional protein-protein interactions with PHLDA1. CONCLUSIONS: The data from this study have built a foundation to develop many hypotheses to further explore the hypoxia/re-oxygenation mechanisms, an area with great clinical significance for multiple diseases.

Spontaneous rupture of the branches of left subclavian artery: A case report and review of the literatures.

RATIONALE: Spontaneous rupture of the branches of left subclavian artery (LSA) without any obvious risk factors is rare. PATIENT CONCERNS: A 51-year-old female patient without history of trauma and hypertension complained about left chest pain. DIAGNOSES: A chest Computed tomography (CT) scan revealed a large pleural effusion (PE) in the left thorax cavity and hemothorax was confirmed by thoracentesis. INTERVENTIONS: The patient underwent surgery. OUTCOMES: spontaneous rupture of the branches of LSAwas confirmed. LESSONS: The patient recovered well and discharged after timely treatments. The unusual possibility should be paid attention in mind in acute chest pain cases.

Immune recovery after fluid resuscitation in rats with severe hemorrhagic shock.

OBJECTIVE: To investigate the effects of resuscitation with normal saline (NS), hypertonic saline (HTS), and hydroxyethyl starch (HES) on regulatory T cells (Tregs), helper T 1 (Th1)/Th2 and cytotoxic T 1 (Tc1)/Tc2 profiles in the treatment of hemorrhagic shock. METHODS: Rats subjected to severe hemorrhagic shock were resuscitated for 30 min with NS (n=8), HTS (n=8), or HES (n=8); sham (n=8) and naive control (n=8) groups were used for comparison. Following fluid resuscitation, the whole shed blood was reinfused for 30 min, and the rats were observed with continuous hemodynamic monitoring for 120 min. CD4+CD25+Foxp3+ Treg proportions, Th1/Th2 and Tc1/Tc2 profiles in spleen were analyzed by three-color flow cytometry. RESULTS: The proportion of CD4+CD25+Foxp3+ Tregs and ratios of Th1/Th2 and Tc1/Tc2 did not differ among control, sham, and HTS groups, but were significantly lower in NS and HES groups (both P<0.05 vs. sham); NS and HES levels were similar. The level of Tc1 was significantly increased in HTS (P<0.05 vs. sham), and levels of Tc2 were increased in NS, HES, and HTS groups compared to sham (all P<0.05), but did not differ from each other. CONCLUSIONS: HTS resuscitation has a greater impact on immune system recovery than NS or HES by preserving the proportion of Tregs and maintaining the balance between Th1/Th2 and Tc1/Tc2 cells in the spleen. Thus, HTS resuscitation provides potential immunomodulatory activity in the early stage after hemorrhagic shock.

Distribution and differentiation of myeloid-derived suppressor cells after fluid resuscitation in mice with hemorrhagic shock.

OBJECTIVE: To investigate the distribution and differentiation of myeloid-derived suppressor cells (MDSCs) in hemorrhagic shock mice, which are resuscitated with normal saline (NS), hypertonic saline (HTS), and hydroxyethyl starch (HES). METHODS: BALB/c mice were randomly divided into control, NS, HTS, and HES resuscitation groups. Three subgroups (n=8) in each resuscitation group were marked as 2, 24, and 72 h. Flow cytometry was used to detect the MDSCs, monocytic MDSCs (M-MDSCs), and granulocytic/neutrophilic MDSCs (G-MDSCs) in peripheral blood nucleated cells (PBNCs), spleen single-cell suspension, and bone marrow nucleated cells (BMNCs). RESULTS: The MDSCs in BMNCs among three resuscitation groups were lower 2 h after shock, in PBNCs of the HTS group were higher, and in spleen of the NS group were lower (all P<0.05 vs. control). The M-MDSC/G-MDSC ratios in PBNCs of the HTS and HES groups were lower (both P<0.05 vs. control). At 24 h, the MDSCs in PBNCs of the NS and HTS groups were higher, while the spleen MDSCs in the HTS group were higher (all P<0.05 vs. control). The M-MDSC/G-MDSC ratios were all less in PBNCs, spleen, and BMNCs of the NS and HTS groups, and were lower in BMNCs of the HES group (all P<0.05 vs. control). At 72 h, the elevated MDSCs in PBNCs were presented in the HTS and HES groups, and in spleen the augment turned up in three resuscitation groups (all P<0.05 vs. control). The inclined ratios to M-MDSC were exhibited in spleen of the NS and HTS groups, and in PBNCs of the NS group; the inclination to G-MDSC in BMNCs was shown in the HES group (all P<0.05 vs. control). CONCLUSIONS: HTS induces the earlier elevation of MDSCs in peripheral blood and spleen, and influences its distribution and differentiation, while HES has a less effect on the distribution but a stronger impact on the differentiation of MDSCs, especially in bone marrow.

Association between the vascular endothelial growth factor single nucleotide polymorphisms and diabetic retinopathy risk: A meta-analysis.

BACKGROUND: The aim of the present study was to reveal the relationship between vascular endothelial growth factor (VEGF) single nucleotide polymorphisms (SNPs) and susceptibility to diabetic retinopathy (DR). METHODS: A literature review was conducted (PubMed, Web of Science, Embase) to identify papers about VEGF SNPs and DR published up to 23 September 2015. The VEGF gene SNPs analyzed with regard to DR susceptibility were rs2010963 (G > C), rs833061 (T > C), rs699947 (C > A), rs3025039 (C > T) and rs1570360 (G > A). Pooled odds ratios (OR) and 95% confidence intervals (CI) were calculated, and meta-analyses were performed using fixed or random effects models. RESULTS: Sixteen studies were included in the meta-analysis. Significant associations between the rs3025039 (C > T) polymorphism and increased DR risk were found in the allele model (T/C; pooled OR 1.60, 95% CI 1.07-2.41, P = 0.02), homozygote model (TT/CC; pooled OR 2.08, 95% CI 1.29-3.35, P = 0.003), heterozygote model (TC/CC; pooled OR 1.68, 95% CI 1.04-2.72, P = 0.04), dominant model (TT+TC/CC; pooled OR 1.72, 95% CI 1.06-2.80, P = 0.03), and recessive model (TT/TC+CC; pooled OR 1.80, 95% CI 1.12-2.90, P = 0.02). For rs833061, a significant association between VEGF SNPs and DR was found only in the allele model (C/T; pooled OR 6.34, 95% CI 2.10-19.14, P = 0.001). CONCLUSIONS: The rs3025039 and rs833061 SNPs are most likely associated with an increased risk of DR. The T allele in rs3025039 and the C allele in rs833061 are associated with increased DR susceptibility.

Early Changes of Peripheral Blood Lymphocyte Subpopulations in Patients with Occupational 2,4-dinitrophenol Poisoning.

2,4-dinitrophenol (DNP), an organic compound which frequently used in industry, is considered to have high toxicity. This study aimed to investigate the early changes of lymphocyte subpopulations in patients with occupational 2,4-DNP poisoning. Totally 9 patients with acute occupational 2,4-DNP poisoning and 30 healthy volunteers as control were enrolled. The patients received immediately comprehensive supportive treatments, including large-dose glucocorticoid and repeated hemoperfusion (HP). The ratio of CD4+/CD8+ T cells were significantly higher in patients upon admission compared to healthy controls (P < 0.01); however, counts of total lymphocytes, CD3+, CD3+CD4+, CD3+CD8+, B (CD19+), and natural killer (NK) cells (CD16+CD56+) were significantly reduced (all P < 0.001). The NK cell count was negatively correlated with initial plasma 2,4-DNP concentration (r = -0.750, P = 0.026). Thus, acute occupational 2,4-DNP poisoning was accompanied by immediate complex immune cell reactions, especially NK cells might play important role in severe 2,4-DNP poisoning.

Evaluation of efficacy of resin hemoperfusion in patients with acute 2,4-dinitrophenol poisoning by dynamic monitoring of plasma toxin concentration.

OBJECTIVE: The intoxications caused by 2,4-dinitrophenol (2,4-DNP), even death, have been frequently reported in recent years. This study aims to investigate the dynamic changes of plasma toxin concentration and explore the clinical value of resin hemoperfusion (HP) in the treatment of patients with acute 2,4-DNP poisoning. METHODS: We reported 16 cases of acute 2,4-DNP poisoning through occupational exposure due to ignoring the risk of poisoning. The blood samples were collected from the 14 survivors. According to the different treatments of resin HP, the survivors were divided into routine HP (n=5) and intensive HP (n=9) groups. Ultra high performance liquid chromatography/ tandem mass spectroscopy (UPLC-MS/MS) was used to detect the 2,4-DNP concentration in plasma in this study. RESULTS: The 14 survivors recovered very well after treatment. The initial plasma 2,4-DNP concentrations (C1) of survivors ranged from 0.25 to 41.88 µg/ml (mean (12.56±13.93) µg/ml). A positive correlation existed between initial plasma 2,4-DNP concentration (C1) and temperature. The elimination of 2,4-DNP was slow and persistent, and the total clearance rates of plasma toxin from the 1st to 3rd day (R3), the 3rd to 7th day (R3-7), and the 1st to 7th day (R7), were only (53.03±14.04)%, (55.25±10.50)%, and (78.29±10.22)%, respectively. The plasma toxin was cleared up to 25 d after poisoning in most of the patients. The R3, R3-7, and R7 in the intensive HP group were all apparently higher than those in the routine HP group, with statistical significance (P<0.05). Simultaneously, the elimination half-life (t1/2) of 2,4-DNP in the intensive HP group was apparently shorter than that in the routine HP group, with statistical significance (P<0.05). CONCLUSIONS: The clinicians should be aware of this slow and persistent process in the elimination of plasma 2,4-DNP. Higher initial plasma toxin concentration resulted in a more severe fever for the patient. According to the limited data, longer and more frequent resin HP may accelerate to eliminate the poison.

Effect of hypertonic versus isotonic saline resuscitation on heme oxygenase-1 expression in visceral organs following hemorrhagic shock in rats.

To compare the early effects of hypertonic and isotonic saline resuscitation on heme oxygenase-1 (HO-1) expression in organs of rats with hemorrhagic shock. Rats were randomly divided into hypertonic saline resuscitation (HTS), normal saline resuscitation (NS) and sham groups. HO-1 mRNA, protein expression and apoptosis were evaluated in organs. In the HTS group, significant difference was noted in HO-1 protein in small intestinal mucosa and liver compared with the NS and sham groups, and in HO-1 mRNA in liver and kidney compared with the sham group. The apoptosis of small intestinal mucosa, liver, heart, and lung was significantly lower in the HTS group than that in the NS group. In this study, small volume resuscitation with HTS can efficiently up-regulate the expression level of HO-1 in small intestinal mucosa and liver, which may be one of the mechanisms alleviating organ damage.

Hypertonic saline resuscitation contributes to early accumulation of circulating myeloid-derived suppressor cells in a rat model of hemorrhagic shock.

BACKGROUND: Hemorrhagic shock is usually associated with complicated immune and inflammatory responses, which are sometimes crucial for the prognosis. As regulators of the immune and inflammatory system; proliferation, migration, distribution and activation of myeloid-derived suppressor cells (MDSCs) are intimately linked to the inflammation cascade. METHODS: In a model of severe hemorrhagic shock, thirty-five rats were randomly divided into control, sham, normal saline resuscitation (NS), hypertonic saline resuscitation (HTS), and hydroxyethyl starch resuscitation (HES), with seven in each group. MDSCs were analyzed by flow cytometric staining of CD11b/c(+)Gra(+) in peripheral blood mononuclear cells (PBMC), spleen cell suspensions, and bone marrow nucleated cells (BMNC). Simultaneously, the expressions of arginase-1 (ARG-1) and inducible nitric oxide synthase (iNOS) mRNA in MDSCs were evaluated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). RESULTS: In the early stage after hemorrhagic shock, fluid resuscitation and emergency treatment, the MDSCs in the PBMC of NS, HTS and HES groups markedly increased, and MDSCs in BMNC of these groups decreased accordingly, significantly different to the control group. In hemorrhagic shock rats infused with HTS at the early resuscitation stage, MDSCs in PBMC increased about 2 and 4 folds, and MDSCs in BMNC decreased about 1.3 and 1.6 folds, as compared to the sham group respectively, with statistically significant difference. Furthermore, compared to the NS and HES groups, the MDSCs in PBMC of HTS group increased 1.6 and 1.8 folds with statistically significant differences; the MDSCs decrease in BMNC was not significant. However, there was no statistically significant difference in MDSCs of spleen among the five groups. In addition, compared to the control, sham, NS and HES groups, the ARG-1 and iNOS mRNA of MDSCs in PBMC, spleen and BMNC in the HTS group had the highest level of expression, but no statistically significant differences were noted. CONCLUSIONS: In this model of rat with severe and controlled hemorrhagic shock, small volume resuscitation with HTS contributes to dramatically early migration and redistribution of MDSCs from bone marrow to peripheral circulation, compared to resuscitation with NS or HES.

Early changes of CD4⁺CD25⁺Foxp3⁺ regulatory T cells and Th1/Th2, Tc1/Tc2 profiles in the peripheral blood of rats with controlled hemorrhagic shock and no fluid resuscitation.

BACKGROUND: Hemorrhagic shock induces immune dysfunction. Regulatory T cells (Tregs), T-helper (Th) cells, and cytotoxic T-lymphocytes (CTLs) can execute many crucial actions in immune and inflammatory responses. This study was conducted to investigate the early pathophysiological changes of CD4(+)CD25(+)Foxp3(+) Treg and Th1/Th2, Tc1/Tc2 profiles in the peripheral blood of rats with controlled hemorrhagic shock and no fluid resuscitation. METHODS: A rat model of controlled hemorrhagic shock with no fluid resuscitation was established. Peripheral blood samples were taken before and four hours after hemorrhagic shock with no fluid resuscitation. Three color flow cytometry was used to detect Tregs, Th1, Th2, Tc1 and Tc2 cells in the samples. RESULTS: In the peripheral blood of rats, the percentage of Tregs four hours after hemorrhagic shock was significantly lower than before hemorrhagic shock (P = 0.001). The ratios of Th1/Th2 and Tc1/Tc2 were changed from (23.08 ± 8.98)% to (23.91 ± 15.36)%, and from (40.40 ± 21.56)% to (65.48 ± 23.88)%, respectively. CONCLUSIONS: At an early stage, the advent of hemorrhagic shock is related to an early decrease of Tregs, and a mild shift in the Th1/Th2, Tc1/Tc2 balance toward Th1 and Tc1 dominance. These changes are part of a hyper-inflammatory state of the host, and will deteriorate the maintenance of immune balance. Further influences and detailed mechanisms need to be investigated.

Lysine acetylsalicylate ameliorates lung injury in rats acutely exposed to paraquat.

BACKGROUND: Paraquat (PQ), an effective and widely used herbicide, has been proven to be safe when appropriately applied to eliminate weeds. However, PQ poisoning is an extremely frustrating clinical condition with a high mortality and with a lack of effective treatments in humans. PQ mainly accumulates in the lung, and the main molecular mechanism of PQ toxicity is based on redox cycling and intracellular oxidative stress generation. The aim of this study was to evaluate whether lysine acetylsalicylate (LAS) could protect the lung from the damage of PQ poisoning and to study the mechanisms of protection. METHODS: A model of PQ poisoning was established in 75 Sprague-Dawley rats by intragastric administration of 50 mg/kg PQ, followed by treatment with 200 mg/kg of LAS. The rats were randomly divided into sham, PQ, and PQ + LAS groups, with 25 in each group. We assessed and compared the malonaldehyde (MDA) content, superoxide dismutase activity (SOD), glutathion peroxidase (GSH-Px), and catalase (CAT) in serum and lung and the hydroxyproline (HYP) content, pathological changes, apoptosis and expression of Bcl-2/Bax protein in lung of rats on days 1, 3, 7, 14 and 21 after PQ poisoning and LAS treatment. RESULTS: Compared to the PQ group rats, early treatment with LAS reduced the MDA and HYP contents, and increased the SOD, GSH-Px, and CAT activities in the serum and lung on days 1, 3, 7, 14, and 21 after PQ poisoning (all P < 0.05). After early LAS treatment, the apoptotic rate and Bax expression of lung decreased, the Bcl-2 expression increased, and the Bcl-2/Bax ratio increased, compared to the PQ group rats. Furthermore, the pathological results of lungs revealed that after LAS treatment, early manifestations of PQ poisoning, such as hemorrhage, edema and inflammatory-cell infiltration, were improved to some degree, and collagen fibers in the pulmonary interstitium were also obviously reduced. CONCLUSION: In this rat model of PQ poisoning, LAS effectively ameliorated the lung injury induced by PQ, possibly through antioxidation, anti-fibrosis, anti-apoptosis, and anticoagulation.

Value of T-tube in biliary tract reconstruction during orthotopic liver transplantation: a meta-analysis.

OBJECTIVE: To compare biliary complications after biliary tract reconstruction with or without T-tube in orthotopic liver transplantation. METHODS: Randomized control trials (RCTs) and comparative studies were identified by a computerized literature search of the Cochrane Library, MEDLINE (1966/1-2010/4), Scopus (1980/1-2010/4), ClinicalTrials.gov (2010/4), the Cochrane Hepato-Biliary Group Controlled Trials Register, and the Cochrane Central Register of Controlled Trials. Studies and data were extracted and assessed independently. Dichotomous outcomes were reported as odds ratios (ORs) and weighted mean difference with 95% confidence intervals (CI). RESULTS: Five RCTs and eight comparative studies with a total of 1 608 subjects were identified. The data showed that the operation with T-tube had better outcomes for duct stenosis (P=0.01, OR=0.45, 95% CI 0.24-0.85). The operations with or without T-tube had equivalent outcomes as follows: overall biliary complications (P=0.85, OR=1.15, 95% CI 0.28-4.72), bile leaks (P=0.38, OR=0.75, 95% CI 0.39-1.42), and cholangitis (P=0.24, OR=4.64, 95% CI 0.36-60.62). These results were strengthened by the analysis of all thirteen non-randomized and randomized studies. CONCLUSIONS: Our systematic review and meta-analysis suggest that the insertion of a T-tube reduces the incidence of biliary stenosis without increasing the incidence of other biliary complications.

Clinical features and treatment in patients with acute 2,4-dinitrophenol poisoning.

OBJECTIVE: To report clinical features and treatment of 16 cases of acute 2,4-dinitrophenol poisoning. METHODS: A total of 16 patients suffering from acute poisoning due to non-oral exposure to 2,4-dinitrophenol were sent to our hospital. Two died within 3 h after admission, while the other 14 responded to supportive treatment and hemoperfusion. Clinical features and treatment of the patients were retrospectively analyzed and presented. RESULTS: Fourteen patients recovered and were discharged after four to six weeks of treatment. No obvious poisoning sequelae were found in the three-month follow-up. CONCLUSIONS: Non-oral exposure to 2,4-dinitrophenol is toxic. Hemoperfusion and glucocorticoid treatments may be efficient measures to prevent mortality, but this requires further study.

Early change of plasma and cerebrospinal fluid arginine vasopressin in traumatic subarachnoid hemorrhage.

OBJECTIVE: To investigate the changes and effects of arginine vasopressin (AVP) in patients with acute traumatic subarachnoid hemorrhage (tSAH). METHODS: The plasma and cerebrospinal fluid (CSF) level of AVP, and intracranial pressure (ICP) were measured in a total of 21 patients within 24 hours after tSAH. The neurological status of the patients was evaluated by Glasgow Coma Scale (GCS). Correlation between AVP and ICP, GCS was analyzed respectively. Meanwhile, 18 healthy volunteers were recruited as control group. RESULTS: Compared with control group, the levels (pg/ml) of AVP in plasma and CSF (x+/-s) in tSAH group were significantly increased within 24 hours (38.72+/-24.71 vs 4.54+/-1.38 and 34.61+/-21.43 vs 4.13+/-.26, P less than 0.01), and was remarkably higher in GCS less than or equal to 8 group than GCS larger than 8 group (50.96+/-36.81 vs 25.26+/-12.87 and 44.68+/-31.72 vs 23.53+/-10.94, P less than 0.05). The CSF AVP level was correlated with ICP (r eqaul to 0.46, P less than 0.05), but no statistically significant correlation was found between plasma AVP, CSF AVP and initial GCS (r equal to -0.29, P larger than 0.05 and r equal to -0.32, P larger than 0.05, respectively). The ICP (mm Hg) in tSAH patients was elevated and higher in GCS less than or equal to 8 group than in GCS larger than 8 group (25.9+/-9.7 vs 17.6+/-5.2, P less than 0.05). CONCLUSION: Our research suggests that AVP is correlated with the severity of tSAH, and may be involved in the pathophysiological process of brain damage in the early stage after tSAH. It seems that compared with the plasma AVP concentration, CSF AVP is more related to the severity of tSAH.

[Prediction and immunologic identification of antigenic epitopes in genus-specific outer membrane protein LipL41 of Leptospira interrogans].

OBJECTIVE: To predict and screen the efficient antigenic epitopes in genus-specific envelope protein LipL41 of Leptospira interrogans and to determine the immunoreactive diversity of LipL41s from different genotypes. METHODS: Bioinformatic methods were applied to predict the T/B combined epitope candidates in LipL41/1 and LipL41/2 molecules. The nucleotide fragments encoding epitopes were amplified by PCR. Phage display system with SDS-PAGE was performed to obtain the recombinant PIIIs containing different T/B combined epitopes. Western Blot assays were performed to determine the immunoreactivity of recombinant PIIIs to various antisera including antiserum against rLipL41/1, rLipL41/2 and whole cell of L.interrogans strain Lai, and serum from patients with leptospirosis. RESULT: Based on the predicting data, eight common or differential combined epitopes in LipL41s were selected. The nucleotide fragments encoding the epitopes were obtained by PCR. All the T/B combined epitope fragments were correctly inserted into the N end of phage PIII protein and then successfully expressed. All the antisera were able to recognize each of the epitopes but the hybridization signal intensity was different. Among these epitopes, the common T/B combined epitopes LipL41/1-30 and LipL41/1-233 showed a stronger and stable hybridization signals. CONCLUSION: All 8 selected T/B combined epitopes in the study are the efficient antigenic epitopes. The common T/B epitopes LipL41/1-30 and LipL41/1-233 can be first used in development of leptospiral MAP vaccine. The cross immunoreaction is between the differential T/B epitopes LipL41s-89,LipL41s-299 and the different antisera.