Ley Antigen Research Articles

Blood group-related antigen Ley on human platelets and its involvement in platelet aggregation via a possible interaction with CD61.

The Ley antigen is a carbohydrate chain belonging to the ABH-Lewis blood group family. Ley has been reported to be present on red blood cells (RBCs) and granulocytes, but its distribution and function in platelets remain unknown. There are a variety of glycoproteins on platelets, which may carry the Ley antigen. This study aims to investigate the expression pattern and the function of Ley in human platelets. Flow cytometry, Western blot, and immunofluorescence assays were performed to determine Ley expression on human platelets. ADP (1.25-10 μM) and thrombin (0.05-1 IU/mL) were used to activate platelets in the presence or absence of prostaglandin E1 (PGE1) and the Ley expression was evaluated again by flow cytometry. Blockade was performed with an anti-Ley monoclonal antibody to verify the role of this epitope in platelet function. Finally, coimmunoprecipitation was performed to identify glycoproteins associated with Ley . Ley was expressed on human platelets independent of ABO blood type. Ley expression was decreased in a dose-dependent manner after activation with either ADP or thrombin, and this effect could be partially reversed by PGE1. Anti- Ley mAb treatment increased alpha-granule release and neutralized the inhibitory effect of the anti-CD61 antibody on platelet aggregation. In addition, Ley was proven to interact and colocalize with CD61. These results demonstrate nondifferential expression of Ley in platelets of different ABO blood types and suggest the involvement of Ley in platelet function, possibly via interaction with CD61.

Synthesis of Lewis Y Analogues and Their Protein Conjugates for Structure-Immunogenicity Relationship Studies of Lewis Y Antigen.

Analogues of cancer-associated Lewis Y (Ley) antigen with varying structures at the reducing end were synthesized by a highly efficient strategy involving one-pot preactivation-based iterative glycosylation to obtain the key tetra-/pentasaccharide intermediates, which was followed by stereoselective fucosylation. After global deprotection, these oligosaccharides were coupled with carrier protein keyhole limpet hemocyanin. The resultant glycan-protein conjugates were subjected to immunological studies in mice. It was disclosed that the conjugate of the pentasaccharide analogue of Lewis Y antigen was more immunogenic than that of the hexasaccharide analogue, but the antisera of both conjugates could indiscriminately recognize each carbohydrate hapten. These results suggested that the short Lewis Y analogue may be utilized to develop functional conjugate cancer vaccines. More importantly, the results also proved that the reducing-end glucose residue in the hexasaccharide analogue of Lewis Y was probably not involved in its interaction with the immune system, whose discovery can have a broad impact on the design of new cancer vaccines.

Association between the ABO blood group and primary knee osteoarthritis: A case–control study

BackgroundRecent studies have suggested association between the ABO blood group and inflammation, which was a crucial pathological process of primary knee osteoarthritis. The aim of this study was to investigate the association between the ABO blood group and primary knee osteoarthritis ​and the severity of primary knee osteoarthritis evaluated by the Kellgren/Lawrence score, as well as the histopathologic association in a subgroup of patients. MethodsWe performed a retrospective review of patients with primary knee osteoarthritis that served as the case group ​and a random sampling of healthy blood donors that served as the control group. The severity of knee osteoarthritis at the first outpatient visit was evaluated by the Kellgren/Lawrence scoring system. Further study was performed to investigate the expression of blood group antigens in synovial tissue of the knee in both cases and controls. ResultsA total of 1126 cases and 30299 controls were involved. The proportion of AB blood group was higher in the case group than in the control group (9.7% vs. 7.8%), and logistic regression revealed that the AB blood group was a risk factor of primary knee osteoarthritis (P ​= ​0.025 and 0.048 for univariate and multivariate analysis, respectively), independent of age (P ​= ​0.973) and sex (P ​= ​0.520). Patients of the blood group AB had a higher Kellgren/Lawrence score (P ​= ​0.017). The immunohistochemical study indicated association between LeY antigen and primary knee osteoarthritis (P ​= ​0.029). ConclusionsThis study suggested that the blood group AB was associated with primary knee osteoarthritis, as well as its radiological severity. Further study indicated that LeY antigen, which was related to the blood group, was associated with primary knee osteoarthritis. Translational potential of this articleThis study revealed that blood group AB and LeY antigen was associated with primary knee osteoarthritis, which shed new light on the nature of osteoarthritis, and the development of novel therapy for osteoarthritis.

Abstract P1-12-02: Clinical efficacy of a humanized monoclonal antibody against the Lewis-Y antigen (Ley): Results of a phase II clinical trial

Abstract Background. The Lewis-Y (Ley) antigen is a blood group-related antigen expressed in over 70% of epithelial cancers. It is expressed in 44% of breast cancers. Objectives. The primary endpoint was to evaluate the clinical efficacy of hu3S193, a humanized monoclonal antibody against the Lewis-Y antigen, in advanced hormone positive breast cancer after failure of at least one line of endocrine therapy. Methods. This multicenter, single arm, phase II trial enrolled eligible patients to receive hu3S193 weekly at a dose of 20 mg/m2 intravenously. Efficacy was measured as clinical benefit rate (objective response or stable disease for at least 24 weeks). Results. Of 49 patients screened, 27 (55%) were Ley positive. Of these 27, only 20 were eligible for efficacy analysis. No complete or partial responses were observed. Five patients had stable disease for 24+ weeks (clinical benefit rate 25%). One patient remains on study drug maintaining stable disease for over 2 years. This patient had high expression of Ley. The most common treatment-related adverse events were headache (50%), cough (45,5%) and nausea/vomiting (31,8%). Conclusions. Hu3S193 lacked sufficient activity in is trial and the investigators stopped accrual at the first interim analysis. High expression of Ley might play a role in selecting patients to this strategy. Citation Format: Testa L, Serrano SV, Arai RJ, Zorzetto MC, Freitas-Junior R, Maletz O, Mano MS, Hoff PM. Clinical efficacy of a humanized monoclonal antibody against the Lewis-Y antigen (Ley): Results of a phase II clinical trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-12-02.

Quantum changes in Helicobacter pylori gene expression accompany host-adaptation.

Helicobacter pylori is a highly successful gastric pathogen. High genomic plasticity allows its adaptation to changing host environments. Complete genomes of H. pylori clinical isolate UM032 and its mice-adapted serial derivatives 298 and 299, generated using both PacBio RS and Illumina MiSeq sequencing technologies, were compared to identify novel elements responsible for host-adaptation. The acquisition of a jhp0562-like allele, which encodes for a galactosyltransferase, was identified in the mice-adapted strains. Our analysis implies a new β-1,4-galactosyltransferase role for this enzyme, essential for Ley antigen expression. Intragenomic recombination between babA and babB genes was also observed. Further, we expanded on the list of candidate genes whose expression patterns have been mediated by upstream homopolymer-length alterations to facilitate host adaption. Importantly, greater than four-fold reduction of mRNA levels was demonstrated in five genes. Among the down-regulated genes, three encode for outer membrane proteins, including BabA, BabB and HopD. As expected, a substantial reduction in BabA protein abundance was detected in mice-adapted strains 298 and 299 via Western analysis. Our results suggest that the expression of Ley antigen and reduced outer membrane protein expressions may facilitate H. pylori colonisation of mouse gastric epithelium.

Relevant Role of Di-Fucosylated Ley Antigen in the Outcome of Locally Advanced Cervical Squamous Cell Carcinoma Patients Treated with Cisplatin Regimen

Background: Several mechanisms are involved in the development of resistance to therapy in LACSCC. Studies have shown that CD44 and Lewis Y antigen (LeY) form a complex that is associated with chemoresistance, tumor invasion and metastasis. We assessed the role of CD44 and LeY in the outcome of LACSCC patients (pts) treated with different chemotherapy regimens. Methods: A total of 126 LACSCC pts FIGO stages IIB-IVA were selected from GOCS databases: 74 pts included in three different prospective phase II trials in the neoadjuvant setting (vinorelbine, docetaxel, ifosfamide-vinorelbinecisplatin) and 52 pts treated with standard radio-chemotherapy based in cisplatin (RCBC). Clinical data at baseline, disease free survival (DFS) and overall survival (OS) were recorded. Univariate and multivariate Cox models were employed. Results: Median age was 45.6 years (range: 24.9 - 80.5). Sixty-three and 47 tumors were CD44+ and LeY+, respectively. Expansive growth tumors showed a higher grade (p=.0024), mitotic index (p=.0505), tumoral necrosis (p=.0191), LeY+ (p=.0034) and CD44+/LeY+ co-expression (p=.0334). CD44+ cells were present in 91.3% of those with local recurrence (p=.0317). Advanced stage was associated with LeY+ tumors (p=.0057). Pts treated with RCBC had worse DFS and OS when their tumors expressed LeY antigen (p=.0083 and p=.0137, respectively). Pre-treatment hemoglobin level, FIGO stage and tumor response remained the most significant prognostic factors in Cox regression. Conclusions: In our cohort of LACSCC pts, the co-expression of CD44+/LeY+ was not associated with worse outcome. However, in the subgroup of pts receiving RCBC, LeY expression was correlated with shorter DFS and OS.

Persistence and Efficacy of Second Generation CAR T Cell Against the LeY Antigen in Acute Myeloid Leukemia

In a phase I study of autologous chimeric antigen receptor (CAR) anti-LeY T-cell therapy of acute myeloid leukemia (AML), we examined the safety and postinfusion persistence of adoptively transferred T cells. Following fludarabine-containing preconditioning, four patients received up to 1.3 × 109 total T cells, of which 14-38% expressed the CAR. Grade 3 or 4 toxicity was not observed. One patient achieved a cytogenetic remission whereas another with active leukemia had a reduction in peripheral blood (PB) blasts and a third showed a protracted remission. Using an aliquot of In111-labeled CAR T cells, we demonstrated trafficking to the bone marrow (BM) in those patients with the greatest clinical benefit. Furthermore, in a patient with leukemia cutis, CAR T cells infiltrated proven sites of disease. Serial PCR of PB and BM for the LeY transgene demonstrated that infused CAR T cells persisted for up to 10 months. Our study supports the feasibility and safety of CAR-T-cell therapy in high-risk AML, and demonstrates durable in vivo persistence.

Structure of the Lectin Regulatory Domain of the Cholesterol-Dependent Cytolysin Lectinolysin Reveals the Basis for Its Lewis Antigen Specificity

The cholesterol-dependent cytolysins (CDCs) punch holes in target cell membranes through a highly regulated process. Streptococcus mitis lectinolysin (LLY) exhibits another layer of regulation with a lectin domain that enhances the pore-forming activity of the toxin. We have determined the crystal structures of the lectin domain by itself and in complex with various glycans that reveal the molecular basis for the Lewis antigen specificity of LLY. A small-angle X-ray scattering study of intact LLY reveals the molecule is flat and elongated with the lectin domain oriented so that the Lewis antigen-binding site is exposed. We suggest that the lectin domain enhances the pore-forming activity of LLY by concentrating toxin molecules at fucose-rich sites on membranes, thus promoting the formation of prepore oligomers on the surface of susceptible cells.

Abstract 5318: Optimizing pharmacokinetics and targeting properties of recombinant anti-Lewis Y antibody hu3S193 in A431 tumor-bearing mice

Abstract Aim: The humanized monoclonal antibody 3S193 (hu3S193) specifically binds the Lewis Y (Ley) antigen and has shown a long half-life in Phase I first-in-man trials. Previous results have shown that mutations in residues I253, H310 and H435 of the Fc region interfere with the neonatal receptor (FcRn) binding. We have generated a hu3S193 antibody with an alanine mutation in residue I253 (I253A) that shows a shorter half-life than parental hu3S193. The objective of this pilot study was to evaluate the radiolabeling properties of 89Zr-labelled hu3S193_I253A compared to its parent hu3S193 and evaluate them as small-animal positron emission tomography (PET) imaging agents. Methods: Site-directed mutagenesis was performed using a QuickChange XL II site-directed mutagenesis kit (Stratagene) to generate the hu3S193_I253A. The LONZA Glutamine Synthetase expression system was used for eukaryotic expression of antibody heavy and kappa light chain vectors. Mutants were produced in transient (Freestyle 293, Invitrogen) cells and tested for Ley binding using ELISA, FACS and BIAcore analysis. Parental hu3S193 and hu3S193_I253A were radiolabelled with 89Zr after conjugation to deferroxamine-p-SCN (Df). The 89Zr-Df-labelled antibodies were evaluated in small-animal PET studies at 4, 24, 48, and 72 hours post injection. At 72 hours after injection, animals were sacrificed. Blood samples were taken via cardiac puncture and organs were removed. Blood and organ samples were counted for radioactivity. Results: Analysis of hu3S193_I253A mutant by ELISA, BIAcore and FACS showed retention of Ley antigen binding ability. PET imaging demonstrated specific tumor uptake of both 89Zr-Df-labeled parental and hu3S193_I253A at 24 hours post injection and this uptake was maintained for 6 days after injection. Lesions as small as 16 mm3 were clearly detected with both agents. Higher uptake in the liver was detected when using 89Zr-Df-labeled hu3S193_I253A. The 72 hour biodistribution data displayed a higher non-specific uptake in the liver with hu3S193_I253A versus parental (i.e. 15 %ID/g versus 6 %ID/g respectively). For comparison, using 111In-CHX-A”-hu3S193_I253A liver uptake was 7 ± 0.3 %ID/g. This observation indicates that improvement to the 89Zr-labelling chemistry could reduce the liver uptake of faster clearing hu3S193 constructs. Conclusion: The pilot study of 89Zr-labelled hu3S193 and hu3S193_I253A demonstrated excellent tumor uptake of both agents, with high-contrast images generated of lesions as small as 16mm3. Improvements in 89Zr radiolabelling chemistry may be required to optimize imaging of fast clearing recombinant antibodies. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5318. doi:10.1158/1538-7445.AM2011-5318

Ex vivo culture of chimeric antigen receptor T cells generates functional CD8+ T cells with effector and central memory-like phenotype

The anti-tumor efficacy of adoptively transferred T cells requires their in vivo persistence and memory polarization. It is unknown if human chimeric antigen receptor (CAR)-expressing T cells can also undergo memory polarization. We examined the functional status of CAR CD8(+) T cells, re-directed to Lewis Y antigen (LeY-T), throughout a period of ex vivo expansion. Immediately before culture CD8(+) T cells comprised a mixture of phenotypes including naive (CD45RA(+)/CCR7(+)/CD27(+)/CD28(+)/perforin-), central memory (CM, CD45RA(-)/CCR7(lo)/CD27(+)/CD28(+)/perforin(lo)), effector memory (EM, CD45RA(-)/CCR7(-)/CD27(+)/CD28(+)/perforin(mod)) and effector (Eff, CD45RA(+)/CCR7(-)/CD27(-)/CD28(-)/perforin(hi)) cells. After transduction and expansion culture of peripheral blood mononuclear cells from normal donors or multiple myeloma patients, CD8(+) LeY-T cells polarized to EM- and CM-like phenotype. CD8(+) LeY-T cells differed from starting CD8(+) CM and EM T cells in that CD27, but not CD28, was downregulated. In addition, CD8(+) LeY-T cells expressed high levels of perforin, similar to starting CD8(+) Eff. CD8(+) LeY-T cells also showed hallmarks of both memory and Eff function, underwent homeostatic proliferation in response to interleukin (IL)-15, and showed interferon (IFN)-γ production and cytotoxicity in response to Le-Y antigen on OVCAR-3 (human ovarian adenocarcinoma) cells. This study confirms CD8(+) LeY-T cells have a CM- and EM-like phenotype and heterogeneous function consistent with potential to persist in vivo after adoptive transfer.

A Phase I Biodistribution and Pharmacokinetic Trial of Humanized Monoclonal Antibody Hu3s193 in Patients with Advanced Epithelial Cancers that Express the Lewis-Y Antigen

We report a first-in-man trial of a humanized antibody (hu3S193) against the Le(y) antigen. Patients with advanced Le(y)-positive cancers received four infusions of hu3S193 at weekly intervals, with four dose levels (5, 10, 20, and 40 mg/m(2)). The first infusion of hu3S193 was trace labeled with Indium-111, and biodistribution, pharmacokinetics, tumor uptake, and immune response were evaluated in all patients. A total of 15 patients (7 male/8 female; age range, 42-76 years; 6 breast, 8 colorectal cancer, and 1 non-small-cell lung cancer) were entered into the study. Transient grade 1 to 2 nausea and vomiting was observed following infusion of hu3S193 at the 40 mg/m(2) dose level only. There was one episode of dose-limiting toxicity with self-limiting Common Toxicity Criteria grade 3 elevated alkaline phosphatase observed in one patient with extensive liver metastases. The biodistribution of (111)In-hu3S193 showed no evidence of any consistent normal tissue uptake, and (111)In-hu3S193 uptake was observed in cutaneous, lymph node, and hepatic metastases. Hu3S193 displayed a long serum half-life (T(1/2)beta = 189.63 +/- 62.17 h). Clinical responses consisted of 4 patients with stable disease and 11 patients with progressive disease, although one patient experienced a 89% decrease in a lymph node mass, and one patient experienced inflammatory symptoms in cutaneous metastases, suggestive of a biological effect of hu3S193. No immune responses (human anti-human antibody) to hu3S193 were observed. Hu3S193 is well tolerated and selectively targets tumors, and the long half-life and biological function in vivo of this antibody makes it an attractive potential therapy for patients with Le(y)-expressing cancers.

Clinical Evaluation of BR96 sFv-PE40 Immunotoxin Therapy in Canine Models of Spontaneously Occurring Invasive Carcinoma

The immunotoxin BR96 sFv-PE40 is an effective antitumor agent against human breast and lung carcinoma xenografts in rodents. This study was designed to (a) determine the frequency with which canine carcinoma cells express Lewis(y) (Le(y)) antigen, thereby identifying canine carcinoma types suitable for the clinical evaluation of BR96 sFv-PE40, and (b) determine the safety and efficacy of BR96 sFv-PE40 in a canine model of spontaneously occurring cancers for investigation of targeted therapy. Carcinoma tissue samples were obtained from client-owned dogs presented for medical care. The tissues were assessed for Le(y) antigen expression using immunohistochemical methods. Dogs with tumors expressing Le(y) antigen were offered enrollment in a clinical trial to receive twice-weekly infusions of 4 to 12 mg/m(2) BR96 sFv-PE40. Clinical toxicity and response data were assessed at each treatment. Twenty-two of 61 carcinomas evaluated were positive for Le(y) expression, including mammary, prostate, lung, and rectal carcinomas, and 12 dogs were enrolled in the clinical trial. The primary side effect was transient emesis. Partial responses or disease stabilization were noted in dogs with inflammatory mammary, bronchogenic, rectal, and tonsillar carcinoma. At least nine of the dogs developed antibodies to the immunotoxin after two to five infusions. Although development of anti-BR96 sFv-PE40 antibodies limited the long-term effectiveness of this immunotoxin in dogs, rapid clinical responses in several aggressive canine carcinomas suggest the immunotoxin has utility for treatment of certain naturally occurring tumors and that its clinical evaluation for treatment of similar human carcinomas is warranted.

Phase I trial of hu3S193 in patients with advanced epithelial cancers which express the Lewis-y antigen

2567 Background: The Lewis-y (Ley) antigen is a blood group related antigen that is expressed in a high proportion of epithelial cancers. We have generated a humanised antibody (hu3S193) against Ley, which has potent immune effector function, and efficacy in murine tumour models (Scott et al, Cancer Res 60: 3254–3261, 2000). Methods: An open label dose escalation Phase I trial of hu3S193 in patients (pts) with advanced Ley positive epithelial cancers has been conducted. Inclusion criteria included +ve Ley expression in tumour assessed prior to study entry. Pts received 4 infusions of hu3S193 at weekly intervals, with four dose levels (5, 10, 20 and 40 mg/m2). The first infusion of hu3S193 was trace labelled with 111In to evaluate targeting. Biodistribution, pharmacokinetics, and immune response were evaluated in all patients. Results: A total of 12 pts (6M:6F; age range 42–76 yrs; 5 breast, 7 colorectal cancer) have been accrued into the study, completing the 5 (3 pts), 10 (6 pts) and 20 (3 pts) mg/m2 dose levels. No infusion related AEs were observed. There was one episode of dose limiting toxicity, at the 10mg/m2 dose level, with Grade 3 liver enzyme rise observed in a pt with extensive liver metastases, which resolved following cessation of hu3S193 infusions. The biodistribution of 111In-hu3S193 showed no normal tissue uptake, and 111In-hu3S193 uptake was observed in cutaneous, lymph node and hepatic metastases. Pharmacokinetic analysis showed no dose dependence of 111In-hu3S193 serum clearance, with a (mean ± SD) T½α 6.2 ± 5.5 hrs, T½β 183.1 ± 66.4 hrs, CL 0.025 ± 0.014 L/hr, V1 3.43 ± 0.63 L. No immune responses (HAHA) were observed in any pt. Two pts had stable disease and 10 PD at restaging. Conclusions: Hu3S193 has promise for immunotherapy of Ley +ve tumours, and further Phase I/II clinical trials are planned. No significant financial relationships to disclose.

Randomized phase II study of SGN-15 (CBR96-doxorubicin immunoconjugate) with docetaxel in patients with advanced or metastatic non-small cell lung cancer (NSCLC)

7039 Background: Docetaxel (Doc) remains the only FDA approved second line chemotherapy for NSCLC, but response rates and survival are low. Targeted therapies may hold more promise. NSCLC cells express a variety of tumor antigens, including the Lewis Y (Ley) antigen. SGN-15 is a novel antibody-drug conjugate that targets Ley, and delivers doxorubicin intracellularly. A multi-center randomized phase II study was conducted to evaluate the safety and efficacy of the combination of SGN-15/Doc as second or third line treatment for patients with advanced NSCLC who have progressed after platinum-based chemotherapy. Methods: In this 2:1 randomized study, 62 patients (pts) were randomly assigned to SGN-15 200 –350 mg/m2 + Doc 35 mg/m2 or Doc alone. A course of therapy was defined as 6 weekly doses within an 8 week period with response evaluation every 8 weeks. Primary endpoint was survival with secondary endpoints including response, toxicity and quality of life, Results: Median overall survival was 7.3 months for...

Chimeric toxins in cancer treatment

A chimeric toxin is composed of a protein toxin connected to a binding ligand such as an antibody or growth factor. Chimeric toxins include conventional immunotoxins, in which the ligand is an antibody, growth-factor fusion toxins, in which the growth factor ligand is fused in single-chain fashion to the toxin, and recombinant immunotoxins, in which the Fv fragment of an antibody is fused to the toxin. Toxins kill cells by catalytic inhibition of protein synthesis within the cell cytosol, and are targeted to cells displaying internalising receptors for the ligand. Chimeric toxins have recently been tested clinically in solid tumours expressing the LeY antigen, the transferrin receptor, and the IL-4 receptor, and in haematologic malignancies expressing CD22, CD19, high affinity IL-2 receptors and CD25. Several chimeric toxins have demonstrated potent clinical efficacy in patients with malignant disease refractory to surgery, radiation therapy and chemotherapy, the traditional modalities of cancer treatment...

Differences in surface-exposed antigen expression between Helicobacter pylori strains isolated from duodenal ulcer patients and from asymptomatic subjects.

We have analyzed possible qualitative and quantitative differences in antigen expression between Helicobacter pylori strains isolated from the antrum and different locations in the duodenum of 21 duodenal ulcer (DU) patients and 20 asymptomatic subjects (AS) by enzyme-linked immunosorbent assay (ELISA) and inhibition ELISA. Almost all antral and duodenal strains grown in vitro expressed the N-acetyl-neuroaminyllactose-binding hemagglutinin, flagellins (subunits FlaA and FlaB), urease, a 26-kDa protein, and a neutrophil-activating protein. In 75% of both the DU patients and the AS, antral H. pylori strains expressed either the blood group antigen Lewis y (Le(y)) alone or together with the Le(x) antigen. However, duodenal H. pylori strains of DU patients expressed Le(y) antigen more frequently than corresponding strains of AS (P < 0.05). Presence of Le(y) on H. pylori was related to the degree of active duodenitis (P < 0.05). Duodenal H. pylori strains isolated from AS were significantly more often Lewis nontypeable than duodenal strains of DU patients (P < 0.01). Presence of H. pylori blood group antigen-binding adhesin (BabA) was significantly higher on both antral and duodenal strains isolated from DU patients than on corresponding strains isolated from AS (P < 0.05). BabA-positive duodenal H. pylori strains isolated from DU patients were associated with active duodenitis more frequently than corresponding strains isolated from AS (P < 0.01). Infection with H. pylori strains positive for Le(y) and BabA in the duodenum is associated with development of duodenal ulcer formation.

Treatment of chronic hepatitis B with adrenal cortical steroid rebound and interferon therapy relationship between mutation in the precore region, LeY antigen and theraputic efficacy of them.

Treatment of chronic hepatitis B with adrenal cortical steroid rebound and interferon therapy relationship between mutation in the precore region, LeY antigen and theraputic efficacy of them.

Ley glycolipid acts as a co‐factor for tumor procoagulant activity

We have generated a monoclonal antibody (MAb), FS01, which inhibits the procoagulant activity (CCA-1) produced by a human squamous cell carcinoma cell line, LK52. Expression of the antigen recognized by FS01 MAb in various cancer cell lines correlated well with the procoagulant activities of the expressing cell lines. Our objective was to characterize the molecule reacting with FS01 MAb and to analyze its involvement in the CCA-1 procoagulant activity. The molecule was identified as a glycolipid and found to be involved in the procoagulant activity because both procoagulant activity and reactivity to FS01 MAb were lost after endoglycoceramidase treatment of CCA-1. Furthermore, FS01 MAb recognized the Lewis Y (Ley) antigen. To confirm the involvement of a glycolipid incorporating the Ley antigen in the procoagulant activity, we attempted to purify CCA-1 from LK52 culture supernatant. In one of the purification steps, a fraction containing low procoagulant activity (CCA-1p) separated from the Ley-positive fraction (CCA-1c). Although CCA-1c alone did not show procoagulant activity, the procoagulant activity of CCA-1p was augmented by CCA-1c and this augmentation was inhibited by FS01 MAb. Furthermore, CCA-1c enhanced the procoagulant activity of 33 cell lines tested as well as CCA-1p. In addition, purified Ley glycolipid from canine intestine augmented the procoagulant activity of CCA-1p, and this augmentation also could be inhibited by FS01 MAb. We conclude that Ley glycolipid is a co-factor for the procoagulant activity derived from cancer cells. Int. J. Cancer 73:903–909, 1997. © 1997 Wiley-Liss, Inc.

Molecular recognition of a peptide mimic of the Lewis Y antigen by an anti-Lewis Y antibody.

Peptides as mimics of carbohydrates display a distinct advantage in vaccine design because of ease of synthesis and their inherent T cell-dependent nature as immunogens. While peptides that mimic carbohydrates have been described, it is not clear how they do so. To further our insight into structural relationships between peptide-mimics and carbohydrate structures, we have analyzed a potential recognition scheme between the murine monoclonal antibody, B3, directed against the tumor-associated antigen Lewis Y oligosaccharide and a peptide identified from phage display screening with B3. The Lewis Y core antigen is a difucosylated structure consisting of four hexose units. The B3 antibody binds to the peptide sequence APWLYGPA in which the putative sequence APWLY is critical for binding to the antibody. Not having experimental structural information for B3, the crystal structure of another anti-Lewis Y antibody, BR96, solved in complex with a nonoate methyl ester Lewis Y tetrasaccharide, provides a molecular basis for LeY antigen recognition and specificity, and how this binding relates to peptide binding. As a guide to place the APWLY motif in the B3 combining site, a fragment library was searched for analogous compounds that have the potential to bind to B3. Our modeling study shows that the B3-peptide complex shares similar recognition features for the difucosylated type 2 lactoseries' structure. This analysis provides a molecular perspective for peptide mimicry of a carbohydrate epitope.

Molecular recognition of a peptide mimic of the Lewis Y antigen by an anti‐Lewis Y antibody

Peptides as mimics of carbohydrates display a distinct advantage in vaccine design because of ease of synthesis and their inherent T cell-dependent nature as immunogens. While peptides that mimic carbohydrates have been described, it is not clear how they do so. To further our insight into structural relationships between peptide-mimics and carbohydrate structures, we have analyzed a potential recognition scheme between the murine monoclonal antibody, B3, directed against the tumor-associated antigen Lewis Y oligosaccharide and a peptide identified from phage display screening with B3. The Lewis Y core antigen is a difucosylated structure consisting of four hexose units. The B3 antibody binds to the peptide sequence APWLYGPA in which the putative sequence APWLY is critical for binding to the antibody. Not having experimental structural information for B3, the crystal structure of another anti-Lewis Y antibody, BR96, solved in complex with a nonoate methyl ester Lewis Y tetrasaccharide, provides a molecular basis for LeY antigen recognition and specificity, and how this binding relates to peptide binding. As a guide to place the APWLY motif in the B3 combining site, a fragment library was searched for analogous compounds that have the potential to bind to B3. Our modeling study shows that the B3-peptide complex shares similar recognition features for the difucosylated type 2 lactoseries' structure. This analysis provides a molecular perspective for peptide mimicry of a carbohydrate epitope. © 1998 John Wiley & Sons, Ltd.