Fragment Antigen Research Articles

Optimizing the Formulation and Lyophilization Process for a Fragment Antigen Binding (Fab) Protein Using Solid-State Hydrogen-Deuterium Exchange Mass Spectrometry (ssHDX-MS).

Solid-state hydrogen-deuterium exchange with mass spectrometry (ssHDX-MS) was evaluated as an analytical method to rapidly screen and select an optimal lyophilized fragment antigen binding protein (Fab) formulation and the optimal lyophilization cycle. ssHDX-MS in lyophilized Fab formulations, varying in stabilizer type and stabilizer/protein ratio, was conducted under controlled humidity and temperature. The extent of deuterium incorporation was measured using mass spectrometry and correlated with solid-state stress degradation at 50 °C as measured by size exclusion chromatography (SEC) and ion-exchange chromatography (IEC). ssHDX-MS was also used to evaluate the impact of three different types of lyophilization processing on storage stability: controlled ice nucleation (CN), uncontrolled ice nucleation (UCN), and annealing (AN). The extent of deuterium incorporation for different Fab formulations agreed with the order of solid-state stress degradation, with formulations having lower deuterium incorporation showing lower stress-induced degradation (aggregation and charge modifications). For lyophilization processing, no significant effect of ice nucleation was observed in either solid-state stress degradation or in the extent of deuterium incorporation for high concentration Fab formulations (25 mg/mL). In contrast, for low concentration Fab formulations (2.5 mg/mL), solid-state stability from different lyophilization processes correlated with the extent of deuterium incorporation. The order of solid-state degradation (AN < CN < UCN) was the same as the extent of deuterium incorporation on ssHDX-MS (AN < CN < UCN). The extent of deuterium incorporation on ssHDX-MS correlated well with the solid-state stress degradation for different Fab formulations and lyophilization processing methods. Thus, ssHDX-MS can be used to rapidly screen and optimize the formulation and lyophilization process for a lyophilized Fab, reducing the need for time-consuming stress degradation studies.

Malaria vaccine candidates displayed on novel virus-like particles are immunogenic and induce transmission-blocking activity.

The development of effective malaria vaccines remains a global health priority. Currently, the most advanced vaccine, known as RTS,S, has only shown modest efficacy in clinical trials. Thus, the development of more efficacious vaccines by improving the formulation of RTS,S for increased efficacy or to interrupt malaria transmission are urgently needed. The RTS,S vaccine is based on the presentation of a fragment of the sporozoite antigen on the surface of virus-like particles (VLPs) based on human hepatitis B virus (HBV). In this study, we have developed and evaluated a novel VLP platform based on duck HBV (known as Metavax) for malaria vaccine development. This platform can incorporate large and complex proteins into VLPs and is produced in a Hansenula cell line compatible with cGMP vaccine production. Here, we have established the expression of leading P. falciparum malaria vaccine candidates as VLPs. This includes Pfs230 and Pfs25, which are candidate transmission-blocking vaccine antigens. We demonstrated that the VLPs effectively induce antibodies to malaria vaccine candidates with minimal induction of antibodies to the duck-HBV scaffold antigen. Antibodies to Pfs230 also recognised native protein on the surface of gametocytes, and antibodies to both Pfs230 and Pfs25 demonstrated transmission-reducing activity in standard membrane feeding assays. These results establish the potential utility of this VLP platform for malaria vaccines, which may be suitable for the development of multi-component vaccines that achieve high vaccine efficacy and transmission-blocking immunity.

Integrating SpyCatcher/SpyTag covalent fusion technology into phage display workflows for rapid antibody discovery

An early bottleneck in the rapid isolation of new antibody fragment binders using in vitro library approaches is the inertia encountered in acquiring and preparing soluble antigen fragments. In this report, we describe a simple, yet powerful strategy that exploits the properties of the SpyCatcher/SpyTag (SpyC/SpyT) covalent interaction to improve substantially the speed and efficiency in obtaining functional antibody clones of interest. We demonstrate that SpyC has broad utility as a protein-fusion tag partner in a eukaryotic expression/secretion context, retaining its functionality and permitting the direct, selective capture and immobilization of soluble antigen fusions using solid phase media coated with a synthetic modified SpyT peptide reagent. In addition, we show that the expressed SpyC-antigen format is highly compatible with downstream antibody phage display selection and screening procedures, requiring minimal post-expression handling with no sample modifications. To illustrate the potential of the approach, we have isolated several fully human germline scFvs that selectively recognize therapeutically relevant native cell surface tumor antigens in various in vitro cell-based assay contexts.

Immunohistochemical Detection of Vasa Antigen and Apoptosis-Related DNA Fragmentation in Ovaries of Sheep Fetuses Prenatally Exposed to Vitamin D Deficiency

Abstract The primordial germ cells (PGCs) in female animals are comprised of diplotene oocytes arrested in the first meiotic prophase. Expression of Vasa is one of the key factors required for subsequent resumption of development and recruitment of PGCs into the growing follicle class. Since vitamin D regulates recruitment of PGCs and developmental competence of ovarian follicles, this study was designed to investigate the expression of Vasa and rate of apoptosis in foetal ovaries prenatally restricted from dietary vitamin D. Nineteen sexually mature Welsh mountain ewes were randomly assigned to vitamin D deficient (VDD) and vitamin D control (VDC) diets from 17d before mating, up to 125d of gestation, when fetal ovaries were collected and fixed in formalin for immunohistochemistry and TUNEL assay. VDD ovaries had fewer healthy oocytes that could stain positive for Vasa as well as a lower integrated density value for DAB staining intensity. Conversely, TUNNEL staining in VDD animals showed a higher integrated density value and percentage of affected area (P&lt;0.05). The present findings indicate that Vasa expression is decreased, while the rate of apoptosis increased in VDD fetal ovaries, and this may adversely affect resumption of growth and development of PGCs reserve.

A disposable fiber optic SPR probe for immunoassay

Immunoassay can be divided into two aspects, one is immobilization of antibodies for the efficient detection of corresponding antigens, and the other is immobilization of antigens to search for antibodies which work against them. In this paper, we demonstrated these two aspects of immunoassay by using the disposable fiber optic biosensors based on surface plasmon resonance (SPR) through surface decoration with half-antibody fragments, which has been scarcely ever reported to the best of our knowledge. We first fabricated the fiber optic SPR biosensor which consists of one gold film coated single-mode fiber sandwiched by two multimode fibers. Then, we decorated the fiber optic SPR biosensors with antibody fragments and antigen fragments, respectively, and compared the specific detection performances of these two kinds of sensors. After surface decoration with half-antibody fragments, the antigen-decorated fiber probe has a demonstrated sensitivity and limit of detection of 0.9771nm/(μg/mL) and 0.1 μg/mL, respectively, which improves by 10 times compared with the performance of the antibody-decorated fiber probe. Additionally, the selective detection results indicate that our proposed biosensor can be employed as a reliable antigen detector or an effective antibody filter. Our proposed sensor has the advantages of miniaturization, low cost, simple usage, label-free detection, high efficiency and sensitivity, and can effectively avoid cross-contamination caused by reuse. Given the reliable and clean detection method for immunoassay, our work should open a new window for the utilization of miniaturized fiber optic sensors in biochemical sensing.

Effect of gefitinib on serum EGFR and CYFRA21-1 in patients with advanced non-small cell lung cancer.

Changes of epidermal growth factor receptor (EGFR) and cytokeratin fragment antigen 21-1 (CYFRA21-1) in patients with advanced non-small cell lung cancer (NSCLC) before and after gefitinib treatment were observed to explore the significance of such changes. A total of 175 patients with advanced NSCLC who were admitted to Hubei Cancer Hospital from July 2012 to October 2015 were collected and divided into two groups: the control group (85 patients who received conventional chemotherapy) and the experimental group (90 patients treated with gefitinib combined with chemotherapy). The serum expression levels of EGFR and CYFRA21-1 were detected by enzyme-linked immunosorbent assay (ELISA). The therapeutic efficacy and 3-year survival of the two groups were compared, and the factors affecting the survival of the patients were analyzed. The total effective rate and local effective rate of the experimental group were significantly higher than those of the control group (P<0.05). Before treatment, no significant difference was detected in the levels of EGFR and CYFRA21-1 between the two groups (P>0.05). After treatment, the expression levels of EGFR and CYFRA21-1 in the two groups were significantly lower than those before treatment (P<0.05). According to the 3-year survival rate, the experimental group was divided into the survival group and the non-survival group. Single factor analysis was performed on the general data, showing that the influencing factors of the survival include the KPS score, smoking history, number of lesions, pathological stage, EGFR, and CYFRA21-1. Gefitinib can bring significantly improved therapeutic efficacy, lower expression levels of EGFR and CYFRA21-1, and longer survival time for patients with advanced NSCLC. Indicators including confirmed smoking history, a KPS score less than or equal to 60 points, multiple lesions, pathological stage IV, high expression of EGFR and CYFRA21-1, are important factors affecting the survival of patient with advanced NSCLC.

Transfer of natural auto-antibodies via egg yolk in chickens divergently selected for natural antibodies binding keyhole limpet hemocyanin

Barcodes of natural auto-antibody (NAAb) profiles based on staining intensity of isotypes binding numbers of self-(tissue) antigen fragments were suggested as parameters for immune diversity, and related to genetic background and health status in man, rodents and poultry. Here, hens, eggs and hatchlings from chicken lines divergently selected and bred for high (H line) or low (L line) total natural antibodies (NAb) levels in plasma binding keyhole limpet hemocyanin (KLH) at 16 weeks of age were tested for their NAAb repertoire binding chicken liver homogenate (CLH) fragments using quantitative Western immunoblotting. The aims of this study were 1. to detect line differences between the H and L line adult hens, eggs and hatchlings for the IgM and IgG isotypes binding CLH fragments, 2. study the presence of NAAb of both isotypes in yolk and albumen, as well as in hatchlings to detect a maternal NAAb transfer route via the egg to the hatchling, and 3. study whether new self-antigen binding isotypes and idiotypes are present in the hatchling.NAAb binding CLH fragments were found in plasma of adult hens (both IgM and IgG), in yolk (IgG only), and hatchlings (mostly IgG, but low levels of IgM). Auto-profiles of IgM showed homogeneity, while IgG profiles were heterogenic between individual hens and individual hatchlings. Significant higher levels as indicated by staining intensity and number of stained CLH fragments were found in plasma of hens genetically selected for high levels of NAb binding KLH. Lines could be clustered based on their auto-profiles indicating that profiles of self-binding IgM and IgG antibodies are genetically based. Visual comparison, clustering and correlation of hens and their hatchlings showed similarities for the IgG, but not the IgM isotype, indicating maternal transfer of IgG NAAb via the yolk. The IgM profile in the hatchlings on the other hand might represent neonatal self-binding antibody formation. As a consequence, hatchlings initially depend for self-binding antibodies on maternal IgG provision during early life.

Glycomics for Type 2 Diabetes Biomarker Discovery: Promise of Immunoglobulin G Subclass-Specific Fragment Crystallizable N-glycosylation in the Uyghur Population.

Aberrant immunoglobulin G (IgG) N-glycosylation offers new prospects to detect changes in cell metabolism and by extension, for biomarker discovery in type 2 diabetes mellitus (T2DM). However, past studies did not analyze the individual IgG subclasses in relation to T2DM pathophysiology. We report here original findings through a comparison of the IgG subclass-specific fragment crystallizable (Fc) glycan biosignatures in 115 T2DM patients with 122 healthy controls within the Uyghur population in China. IgG Fc glycosylation profiles were analyzed using nano-liquid chromatography-mass spectrometry to exclude changes attributed to fragment antigen binding N-glycosylation. After correction for clinical covariates, 27 directly measured and 4 derived glycan traits of the IgG subclass-specific N-glycopeptides were significantly associated with T2DM. Furthermore, we observed in T2DM a decrease in bisecting N-acetylglucosamine of IgG2 and agalactosylation of IgG4, and an increase in sialylation of IgG4 and digalactosylation of IgG2. Classification model based on IgG subclass-specific N-glycan traits was able to distinguish patients with T2DM from controls with an area under the receiver operating characteristic curve of 0.927 (95% confidence interval 0.894-0.960, p < 0.001). In conclusion, a robust association between the IgG subclass-specific Fc N-glycomes and T2DM was observed in the Uyghur population sample in China, suggesting a potential for the IgG Fc glycosylation as a biomarker candidate for type 2 diabetes. The integration of glycomics with other system science biomarkers might offer further hope for innovation in diagnosis and treatment of T2DM in the future. Finally, it is noteworthy that "Population Glycomics" is an emerging approach to biomarker discovery for common complex diseases.

Design of Construct Carrying GmDREB6 to Enhance Soybean Gene Expression Related to Abiotic Stress Response

Glycine max (L.) Merrill is a crop that brings a lot of economic and nutritive values, however soybean is quite sensitive to stress. The applications of gene technology can improve resistance of soybean plants against external stress factors. The aim of this study was to conduct a transgenic vector containing GmDREB6 gene and determine the expression of gene encoding GmDREB6 in Nicotiana tabacum before transforming into soybean plants. The GmDREB6 artificial gene was synthesized containing nucleotide fragment encoding 230 amino acids, nucleotide fragment encoding cmyc antigen and nucleotide fragments with cut-off points of XbaI/SacI enzyme pair. The results indicated that the 35S-GmDREB6-cmyc construct was designed and transferred into tobacco plants. The GmDREB6 was incorporated in the genome and was expressed in transgenic tobacco plants at the transcriptional level. The transgenic vector pBI121_GmDREB6 well worked on the model tobacco plants. Therefore, it can be used for transferring into soybean plants to enhance soybean tolerance to abiotic stress.

Design of Construct Carrying GmDREB6 to Enhance Soybean Gene Expression Related to Abiotic Stress Response

Glycine max (L.) Merrill is a crop that brings a lot of economic and nutritive values, however soybean is quite sensitive to stress. The applications of gene technology can improve resistance of soybean plants against external stress factors. The aim of this study was to conduct a transgenic vector containing GmDREB6 gene and determine the expression of gene encoding GmDREB6 in Nicotiana tabacum before transforming into soybean plants. The GmDREB6 artificial gene was synthesized containing nucleotide fragment encoding 230 amino acids, nucleotide fragment encoding cmyc antigen and nucleotide fragments with cut-off points of XbaI/SacI enzyme pair. The results indicated that the 35S-GmDREB6-cmyc construct was designed and transferred into tobacco plants. The GmDREB6 was incorporated in the genome and was expressed in transgenic tobacco plants at the transcriptional level. The transgenic vector pBI121_GmDREB6 well worked on the model tobacco plants. Therefore, it can be used for transferring into soybean plants to enhance soybean tolerance to abiotic stress.

Antigenicity and immunogenicity analysis of Xinjiang hemorrhagic fever virus Gc antigen fragment

Objective To express and purify two domains GcⅠ and GcⅡ of Xinjiang hemorrhagic fever virus (XHFV) glycoprotein, and to study its immunogenicity and the effects on immune response in mice. Methods The prokaryotic expression plasmids of pET28a-GcⅠ and pET32a-GcⅡ were constructed and transformed into E. coli BL21, respectively. The expression and purification conditions of rGcⅠ and rGcⅡ proteins were optimized. The antigenicity of the fusion protein was detected by Western Blot and enzyme-linked immunosorbent assay (ELISA). BALB/c mice were immunized by protein immunization and DNA priming-protein boosting. The mice were randomly divided into 5 groups, including pVAX1-GcⅠ+rGcⅠ group, pVAX1-GcⅡ+rGcⅡ group, rGcⅠ group, rGcⅡ group and saline group (control group) with 7 mice in each group. The serum antibody titer of mice was detected by indirect ELISA, and the immune effect was evaluated by spleen T lymphocyte proliferation assay and cytokine content determination. Results The fusion proteins rGcⅠ and rGcⅡ were purified and obtained, which could react with positive serum of sheep and had good antigenicity. After three immunizations, the IgG levels in the serum of each experimental group were significantly higher than those in the control group (all P<0.001). The serum antibody titers of the experimental groups were reached above 1∶12 800. Among them, the concentration of Th2 type cytokine interleukin-4 (IL-4) in the spleen cell culture supernatant of rGcⅡ [(79.97±7.47) ng/L] and pVAX1-GcⅡ+rGcⅡ group [(61.43±9.27) ng/L] was significantly higher than (24.29±3.81) ng/L of the control group, respectively (all P<0.01). The highest mass concentration [(42.46±2.60) ng/L] of Th1 type cytokine interferon-γ (IFN-γ) was observed in the pVAX1-GcⅡ+rGcⅡ group, which was significantly higher than (20.33±1.67) ng/L of the control group, and the difference was statistically significant (P<0.001). That showed a significant antigen-specific splenic T lymphocyte proliferation (P<0.001). Conclusions The purified recombinant proteins rGcⅠand rGcⅡhave good immunogenicity, which can make the immune system T lymphocytes tend to Th2 response, and pVAX1-GcⅡ combined with recombinant protein GcⅡ can induce better antigen-specific immune effect. And pVAX1-GcⅡ combined with recombinant protein GcⅡ is expected to be used as vaccine candidates for the prevention and control of XHFV. Key words: Xinjiang hemorrhagic fever virus; Glycoprotein; Prokaryotic expression; Purification; Immunogenicity

The first study on the usefulness of recombinant tetravalent chimeric proteins containing fragments of SAG2, GRA1, ROP1 and AMA1 antigens in the detection of specific anti-Toxoplasma gondii antibodies in mouse and human sera.

This study presents an evaluation of four tetravalent recombinant chimeric proteins containing fragments of the Toxoplasma gondii antigens, SAG2, GRA1, ROP1 and AMA1, as potential replacements of a the soluble, whole-cell tachyzoite lysate (TLA) used in serological assays. Recombinant chimeric proteins (SAG2-GRA1-ROP1-AMA1N, AMA1N-SAG2-GRA1-ROP1, AMA1C-SAG2-GRA1-ROP1, and AMA1-SAG2-GRA1-ROP1) obtained by genetic engineering were tested for their reactivity with specific IgM and IgG antibodies from sera of experimentally infected mice and humans with T. gondii infection using an enzyme-linked immunosorbent assay (ELISA). In total 192 serum samples from patients with acquired T. gondii infection and 137 sera from seronegative individuals were examined. The reactivity of chimeric antigens with antibodies generated during T. gondii invasion was measured and compared to the results obtained in assays based on whole-cell Toxoplasma antigen. Chimeric proteins proved effective in differentiation between T. gondii-infected and uninfected individuals (100% sensitivity and specificity in the IgG ELISAs) which shows their potential usefulness as a replacements for TLA in standardized commercial tests for the serodiagnosis of toxoplasmosis. In addition, the chimeric proteins were tested for use in avidity determination. Obtained results were comparable to those of the corresponding commercial assays, suggesting the utility of these proteins for avidity assessment. Furthermore, this study demonstrated that the AMA1-SAG2-GRA1-ROP1 chimeric protein has the potential to distinguish specific antibodies from serum samples of individuals with the early and chronic phase of T. gondii infection.

Clinical use of tumor biomarkers in prediction for prognosis and chemotherapeutic effect in esophageal squamous cell carcinoma

BackgroundGrowing evidence has indicated that tumor biomarkers, including cytokeratin 19 fragment antigen 21–1 (Cyfra21–1), carbohydrate antigen 19–9 (CA19–9), carbohydrate antigen 72–4 (CA72–4), carcinoembryonic antigen (CEA) and squamous cell carcinoma antigen (SCC-Ag) were reported to be commonly used in diagnosis and prognosis in esophageal squamous cell carcinoma (ESCC). However, which is the best marker for predicting prognosis remains unknown. Few papers focused on the relationship between tumor biomarkers and postoperative treatment in ESCC.MethodsA total of 416 ESCC patients were enrolled in this study. The association between tumor markers and overall survival (OS) was analyzed using Kaplan-Meier method with log-rank test, followed by multivariate Cox regression models.ResultsThe results of Cox multivariate analysis indicated that among these tumor biomarkers, CA19–9 (≥ 37 vs. < 37) [hazard ratio (HR) = 2.130, 95% confidence interval (CI) = 1.138–3.986, p = 0.018] and CEA (≥ 5 vs. < 5) (HR = 1.827, 95% CI = 1.089–3.064, p = 0.022) were the independent prognostic factors of poor OS. For the ESCC patients with CA19–9 < 37, CEA < 5 or SCC-Ag < 1.5, the surgery plus postoperative chemotherapy group had a significantly longer OS than the surgery group alone (p < 0.05), but this significant difference of OS between these two groups cannot be found in patients with CA19–9 ≥ 37, CEA ≥ 5 or SCC-Ag ≥ 1.5 (p > 0.05).ConclusionsCEA and CA19–9 maybe are superior to other tumor biomarkers as prognostic indicators in ESCC. CA19–9, CEA, SCC-Ag may be useful in predicting the therapeutic effect of postoperative chemotherapy in ESCC.

Human Monocyte-Derived Dendritic Cells Produce Millimolar Concentrations of ROS in Phagosomes Per Second.

Neutrophils kill ingested pathogens by the so-called oxidative burst, where reactive oxygen species (ROS) are produced in the lumen of phagosomes at very high rates (mM/s), although these rates can only be maintained for a short period (minutes). In contrast, dendritic cells produce ROS at much lower rates, but they can sustain production for much longer after pathogen uptake (hours). It is becoming increasingly clear that this slow but prolonged ROS production is essential for antigen cross-presentation to activate cytolytic T cells, and for shaping the repertoire of antigen fragments for presentation to helper T cells. However, despite this importance of ROS production by dendritic cells for activation of the adaptive immune system, their actual ROS production rates have never been quantified. Here, we quantified ROS production in human monocyte-derived dendritic cells by measuring the oxygen consumption rate during phagocytosis. Although a large variation in oxygen consumption and phagocytic capacity was present among individuals and cells, we estimate a ROS production rate of on average ~0.5 mM/s per phagosome. Quantitative microscopy approaches showed that ROS is produced within minutes after pathogen encounter at the nascent phagocytic cup. H2DCFDA measurements revealed that ROS production is sustained for at least ~10 h after uptake. While ROS are produced by dendritic cells at an about 10-fold lower rate than by neutrophils, the net total ROS production is approximately similar. These are the first quantitative estimates of ROS production by a cell capable of antigen cross-presentation. Our findings provide a quantitative insight in how ROS affect dendritic cell function.

Predictive significance of CYFRA21-1, squamous cell carcinoma antigen and carcinoembryonic antigen for lymph node metastasis in patients with esophageal squamous cancer.

From January 2018 to May 2018, 108 patients with thoracic esophageal cancer underwent esophagectomy with two- to three-field lymph node dissection. Serum cytokeratin 19 fragment antigen 21-1 (CYFRA21-1), squamous cell carcinoma antigen, and carcinoembryonic antigen levels were detected before surgery. Preoperative serum levels of CYFRA21-1 and squamous cell carcinoma antigen were correlated closely with pN stage (P = 0.000 and P = 0.045). CYFRA21-1 and pathological T status were independent predictors of lymph node metastasis (P = 0.000). The area under the curve values of CYFRA21-1 and squamous cell carcinoma antigen for predicting lymph node metastasis were 0.731 (P =0.000) and 0.650 (P =0.007), respectively. Our study demonstrated that serum CYFRA21-1 and squamous cell carcinoma antigen levels were associated with lymph node metastasis in esophageal squamous cell carcinoma, especially in patients at the early T stage. The preoperative serum CYFRA21-1 level was an independent predictor of lymph node metastasis.

Performance evaluation of 3 serodiagnostic peptide epitopes and the derived multi-epitope peptide OvNMP-48 for detection of Onchocerca volvulus infection

Current diagnostic tools to determine infection with the helminth parasite Onchocerca volvulus have limited performance characteristics. In previous studies, a proteome-wide screen was conducted to identify linear epitopes in this parasite’s proteome, resulting in the discovery of 1110 antigenic peptide fragments. Here, we investigated three of these peptides using peptide ELISA’s and evaluated their sensitivity and specificity. Epitope mapping was performed, and peptides were constructed that contained only the minimal epitope, flanked by a linker. Investigation of the performance of these minimal epitope peptides demonstrated that all three of them have a specificity (as defined by lack of response in non-helminth-infected individuals) of 100%, low cross-reactivity (5.6%, 5.6%, and 9.3%, respectively), but low sensitivity (36.9%, 46.5%, and 41.2%, respectively). Some cross-reactivity was observed in samples from individuals infected with soil-transmitted helminths or Brugia malayi. Combining these three minimal epitopes in a single peptide, called OvNMP-48, resulted in a performance that exceeded the sum of the individual epitopes, with a sensitivity of 76.0%, a specificity of 97.4%, and a cross-reactivity of 11.1%. Cross-reactivity was observed in some STH and Brugia malayi-infected individuals. This work opens the opportunity to start exploring how these novel linear epitope markers might become part of the O. volvulus diagnostic toolbox.

The serum level of CC chemokine ligand 18 correlates with the prognosis of non-small cell lung cancer.

CC chemokine ligand 18 (CCL18) is a chemotactic cytokine involved in the pathogenesis and progression of various cancers. Our previous research showed that the expression of CCL18 is obviously higher in non-small cell lung cancer (NSCLC) than in the adjacent normal tissues, suggesting its role in NSCLC. We further examined the serum level of CCL18 in 80 NSCLC patients with enzyme-linked immunosorbent assay and simultaneously analyzed the survival curve of these patients by the Kaplan-Meier method, and then utilized a log-rank test to evaluate the correlation of CCL18 expression with the malignant progression of NSCLC. Our results showed that the median serum concentration of CCL18 was significantly elevated to 436.11 ng/mL in NSCLC patients compared to 41.97 ng/ml in healthy people (P<0.01), which was also positively related to the expression of lung cancer biomarkers carcinoma-embryonic antigen and cytokeratin fragment antigen 21-1. Moreover, correlation analysis showed that an increased level of serum CCL18 was associated with a worse survival time in NSCLC patients. Our findings suggest that the serum CCL18 level of NSCLC patients was negatively correlated with the prognosis, thus suggesting that CCL18 may serve as a potential circulating biomarker for NSCLC diagnosis.

Modulation of TAP-dependent antigen compartmentalization during human monocyte-to-DC differentiation

AbstractDendritic cells (DCs) take up antigen in the periphery, migrate to secondary lymphoid organs, and present processed antigen fragments to adaptive immune cells and thus prime antigen-specific immunity. During local inflammation, recirculating monocytes are recruited from blood to the inflamed tissue, where they differentiate to macrophages and DCs. In this study, we found that monocytes showed high transporter associated with antigen processing (TAP)–dependent peptide compartmentalization and that after antigen pulsing, they were not able to efficiently stimulate antigen-specific T lymphocytes. Nevertheless, upon in vitro differentiation to monocyte-derived DCs, TAP-dependent peptide compartmentalization as well as surface major histocompatibility complex I turnover decreased and the cells efficiently restimulated T lymphocytes. Although TAP-dependent peptide compartmentalization decreased during DC differentiation, TAP expression levels increased. Furthermore, TAP relocated from early endosomes in monocytes to the endoplasmic reticulum (ER) and lysosomal compartments in DCs. Collectively, these data are compatible with the model that during monocyte-to-DC differentiation, the subcellular relocation of TAP and the regulation of its activity assure spatiotemporal separation of local antigen uptake and processing by monocytes and efficient T-lymphocyte stimulation by DCs.

Generation and characterization of D-dimer specific monoclonal antibodies for use in latex agglutination test.

The commercially available D-dimer assays used in the clinical practice often show differences in the results, and their specificity and sensitivity are rather unsatisfactory. Our aim was to develop a new monoclonal antibody against D-dimer with a proper specificity, and estimating its suitability using in a latex agglutination diagnostic test. Monoclonal antibodies were generated using hybridoma technology. Their titer was determined by a self-developed ELISA method. The cross-reactions of the antibodies were tested. Characterization of the epitope specificity of a selected antibody was performed through digestion of D-dimer followed by Western blotting. The amino acid sequences of the active antigen fragments were determined. According to the ELISA results, 38 cell groups were constated as antibody-producing hybridomas, among them 7 gave raised titer of antibody and were cloned. Based on the cross-reaction analysis, none of the antibodies gave cross-reaction with fibrin-E and fibrinogen-E fragments but reacted with fibrin D and fibrinogen D fragments. A low cross-reaction was showed with fibrinogen and fibrin X and Y. Contrary to the others, antibody 2B9 gave no cross-reaction with fibrinogen and reacted weakly with fibrin X and Y fragments. According to the epitope analysis the antibody 2B9 binds to amino acids 94–99 and to amino acids 140–147 on the beta chain and it recognizes the amino acids 23–32 and 93–98 on the gamma chain of D-dimer. Considering the characteristics of the above mentioned monoclonal antibody 2B9, we found that it is suitable to be a basis for a D-dimer diagnostic test with proper specificity.

Heteromultivalent Glycooligomers as Mimetics of Blood Group Antigens.

Precision glycomacromolecules have proven to be important tools for the investigation of multivalent carbohydrate-lectin interactions by presenting multiple glycan epitopes on a highly-defined synthetic scaffold. Herein, we present a new strategy for the versatile assembly of heteromultivalent glycomacromolecules that contain different carbohydrate motifs in proximity within the side chains. A new building block suitable for the solid-phase polymer synthesis of precision glycomacromolecules was developed with a branching point in the side chain that bears a free alkyne and a TIPS-protected alkyne moiety, which enables the subsequent attachment of different carbohydrate motifs by on-resin copper-mediated azide-alkyne cycloaddition reactions. Applying this synthetic strategy, heteromultivalent glycooligomers presenting fragments of histo-blood group antigens and human milk oligosaccharides were synthesized and tested for their binding behavior towards bacterial lectin LecB.