Frequency of Duffy, Kidd, Lewis, and Rh Blood Group Antigens and Phenotypes Among Donors in the Al-Ahsa Region, Saudi Arabia.

BACKGROUND: In Al-Ahsa, Saudi Arabia, the high consanguinity rates contribute to the prevalence of inherited hemoglobinopathies such as sickle cell disease and thalassemia, which frequently require blood transfusions. These transfusions carry the risk of alloimmunization, necessitating a precise blood component matching to mitigate health risks. Local antigen frequency data is vital for optimizing transfusion practices and enhancing the safety of these medical procedures for the Al-Ahsa population. METHODS: This study investigated the distribution of Duffy, Kidd, Lewis, and Rh blood group antigens in 1,549 individuals from the region; comparing the frequencies with global data. RESULTS: Serological analyses revealed a high prevalence of the Fy(a+b-) and Jk(a+b+) phenotypes in the Duffy and Kidd blood groups, respectively, with Jk(a-b-) being notably scarce. The Lewis blood group exhibited a significant presence of Le(a-b+) and Le(a+b-) phenotypes, whereas Le(a+b+) was less common. In the Rh system, the D antigen was most prevalent, with other antigens following in descending order of frequency. CONCLUSIONS: The study underscores the regional variation in antigen frequencies, emphasizing the need for local blood banks to adapt their screening and matching practices to mitigate the risk of alloimmunization and enhance transfusion safety. These findings are pivotal for refining transfusion strategies and understanding the immunohematology landscape in Al-Ahsa.

East-Asian Helicobacter pylori strains synthesize heptan-deficient lipopolysaccharide.

The lipopolysaccharide O-antigen structure expressed by the European Helicobacter pylori model strain G27 encompasses a trisaccharide, an intervening glucan-heptan and distal Lewis antigens that promote immune escape. However, several gaps still remain in the corresponding biosynthetic pathway. Here, systematic mutagenesis of glycosyltransferase genes in G27 combined with lipopolysaccharide structural analysis, uncovered HP0102 as the trisaccharide fucosyltransferase, HP1283 as the heptan transferase, and HP1578 as the GlcNAc transferase that initiates the synthesis of Lewis antigens onto the heptan motif. Comparative genomic analysis of G27 lipopolysaccharide biosynthetic genes in strains of different ethnic origin revealed that East-Asian strains lack the HP1283/HP1578 genes but contain an additional copy of HP1105 and JHP0562. Further correlation of different lipopolysaccharide structures with corresponding gene contents led us to propose that the second copy of HP1105 and the JHP0562 may function as the GlcNAc and Gal transferase, respectively, to initiate synthesis of the Lewis antigen onto the Glc-Trio-Core in East-Asian strains lacking the HP1283/HP1578 genes. In view of the high gastric cancer rate in East Asia, the absence of the HP1283/HP1578 genes in East-Asian H. pylori strains warrants future studies addressing the role of the lipopolysaccharide heptan in pathogenesis.

Lewis and ABO histo-blood types and the secretor status of patients hospitalized with COVID-19 implicate a role for ABO antibodies in susceptibility to infection with SARS-CoV-2.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) targets the respiratory and gastric epithelium, causing coronavirus disease 2019 (COVID-19). Tissue antigen expression variations influence host susceptibility to many infections. This study aimed to investigate the closely linked Lewis (FUT3) and ABO histo-blood types, including secretor (FUT2) status, to infections with SARS-CoV-2 and the corresponding severity of COVID-19. STUDY DESIGN AND METHODS: Patients (Caucasians, n = 338) were genotyped for ABO, FUT3, and FUT2, and compared to a reference population of blood donors (n = 250,298). The association between blood types and severity of COVID-19 was addressed by dividing patients into four categories: hospitalized individuals in general wards, patients admitted to the intensive care unit with and without intubation, and deceased patients. Comorbidities were considered in subsequent analyses. RESULTS: Patients with blood type Lewis (a-b-) or O were significantly less likely to be hospitalized (odds ratio [OR] 0.669, confidence interval [CI] 0.446-0.971, OR 0.710, CI 0.556-0.900, respectively), while type AB was significantly more prevalent in the patient cohort (OR 1.519, CI 1.014-2.203). The proportions of secretors/nonsecretors, and Lewis a+ or Lewis b+ types were consistent between patients and controls. The analyzed blood groups were not associated with the clinical outcome as defined. DISCUSSION: Blood types Lewis (a-b-) and O were found to be protective factors, whereas the group AB is suggested to be a risk factor for COVID-19. The antigens investigated may not be prognostic for disease severity, but a role for ABO isoagglutinins in SARS-CoV-2 infections is strongly suggested.

Molecular and structural basis for Lewis glycan recognition by a cancer-targeting antibody.

Immunotherapy has been successful in treating many tumour types. The development of additional tumour-antigen binding monoclonal antibodies (mAbs) will help expand the range of immunotherapeutic targets. Lewis histo-blood group and related glycans are overexpressed on many carcinomas, including those of the colon, lung, breast, prostate and ovary, and can therefore be selectively targeted by mAbs. Here we examine the molecular and structural basis for recognition of extended Lea and Lex containing glycans by a chimeric mAb. Both the murine (FG88.2) IgG3 and a chimeric (ch88.2) IgG1 mAb variants showed reactivity to colorectal cancer cells leading to significantly reduced cell viability. We determined the X-ray structure of the unliganded ch88.2 fragment antigen-binding (Fab) containing two Fabs in the unit cell. A combination of molecular docking, glycan grafting and molecular dynamics simulations predicts two distinct subsites for recognition of Lea and Lex trisaccharides. While light chain residues were exclusively used for Lea binding, recognition of Lex involved both light and heavy chain residues. An extended groove is predicted to accommodate the Lea-Lex hexasaccharide with adjoining subsites for each trisaccharide. The molecular and structural details of the ch88.2 mAb presented here provide insight into its cross-reactivity for various Lea and Lex containing glycans. Furthermore, the predicted interactions with extended epitopes likely explains the selectivity of this antibody for targeting Lewis-positive tumours.

Human adenovirus type 5 increases host cell fucosylation and modifies Ley antigen expression.

Certain viral infections are known to modify the glycosylation profile of infected cells through the overexpression of specific host cell fucosyltransferases (FUTs). Infection with CMV (cytomegalovirus), HCV (hepatitis C virus), HSV-1 (herpes simplex virus type-1) and VZV (varicella-zoster virus) increase the expression of fucosylated epitopes, including antigens sLex (Siaα2-3 Galß1-4(Fucα1-3)GlcNAcß1-R) and Ley (Fucα1-2 Galß1-4(Fucα1-3)GlcNAcß1-R). The reorganization of the glycocalyx induced by viral infection may favor the spread of viral progeny, and alter diverse biological functions mediated by glycans, including recognition by the adaptive immune system. In this work, we aimed to establish whether infection with human adenovirus type 5 (HAd5), a well-known viral vector and infectious agent, causes changes in the glycosylation profile of A549 cells, used as a model of lung epithelium, a natural target of HAd5. We demonstrate for the first time that HAd5 infection causes a significant increase in the cell surface de novo fucosylation, as assessed by metabolic labeling, and that such modification is dependent on the expression of viral genes. The main type of increased fucosylation was determined to be in α1-2 linkage, as assessed by UEA-I lectin binding and supported by the overexpression of FUT1 and FUT2. Also, HAd5-infected cells showed a heterogeneous change in the expression profile of the bi-fucosylated Ley antigen, an antigen associated with enhanced cell proliferation and inhibition of apoptosis.

Upregulation of MUC5AC production and deposition of LEWIS determinants by HELICOBACTER PYLORI facilitate gastric tissue colonization and the maintenance of infection.

BACKGROUND: Helicobacter pylori bacteria colonize human gastric mucosa, cause chronic inflammation, peptic ulcers and gastric cancer. Colonization is mediated by H. pylori adhesins, which preferentially bind mucin 5 (MUC5AC) and Lewis (Le) determinants. The aim of this study was to evaluate the influence of H. pylori and their components on MUC5AC production and deposition of LeX/LeY in gastric epithelial cells in relation to bacterial adhesion using Caviae porcellus primary gastric epithelial cells and an in vivo model of experimental H. pylori infection in these animals. METHODS: MUCA5C and LeX/LeY were induced in vitro by live H. pylori reference strain CCUG 17874 (2 × 107 CFU/ml), H. pylori glycine acid extract (GE), 10 µg/ml; cytotoxin associated gene A (CagA) protein, 1 µl/ml; UreA urease subunit, 5 µg/ml; lipopolysaccharide (LPS) 25 ng/ml and imaged by fluorescence microscopy after anti-MUC5AC or anti-LeX/LeY FITC antibody staining. Bacterial adhesion was imaged by using anti-H. pylori FITC antibodies. The animals were inoculated per os with H. pylori (3 times in 2 days intervals, 1 × 1010 CFU/ml). After 7 or 28 days an infection and inflammation were assessed by histological, serological and molecular methods. Gastric tissue sections of infected and control animals were screend for MUCA5C and LeX, and H. pylori adhesion as above. RESULTS: MUC5AC production and deposition of Lewis determinants, especially LeX were upregulated in the milieu of live H. pylori as well as GE, CagA, UreA or LPS in vitro and in vivo during infection, more effectively in the acute (7 days) than in the chronic (28 days) phase of infection. This was related to enhanced adhesion of H. pylori, which was abrogated by anti-MUC5AC and anti-LeX or anti-LeY antibody treatment. CONCLUSIONS: Modulation of MUCA5C production and LeX/LeY deposition in the gastric mucosa by H. pylori can significantly increase gastric tissue colonization during H. pylori infection.

Biologic roles of the ABH and Lewis histo-blood group antigens Part I: infection and immunity.

The ABH and Lewis antigens were among the first of the human red blood cell polymorphisms to be identified and, in the case of the former, play a dominant role in transfusion and transplantation. But these two therapies are largely twentieth century innovations, and the ABH and related carbohydrate antigens are not only expressed on a very wide range of human tissues, but were present in primates long before modern humans evolved. Although we have learned a great deal about the biochemistry and genetics of these structures, the biological roles that they play in human health and disease are incompletely understood. This review and its companion, to appear in a later issue of Vox Sanguinis, will focus on a few of the biologic and pathologic processes which appear to be affected by histo-blood group phenotype. The first of the two reviews will explore the interactions of two bacteria with the ABH and Lewis glycoconjugates of their human host cells, and describe the possible connections between the immune response of the human host to infection and the development of the AB-isoagglutinins. The second review will describe the relationship between ABO phenotype and thromboembolic disease, cardio-vascular disease states, and general metabolism.

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.

Immune responses against Lewis Y tumor-associated carbohydrate antigen displayed densely on self-assembling nanocarriers.

Immune responses against Lewis y (LY) displayed on nanocarriers at different surface densities were studied. The high surface density of LY was obtained by the A2B-type amphiphilic polypeptides having LY at the two terminals [LY-poly(sarcosine)2-b-(l- or d-Leu-Aib)6]. The equimolar mixture of these two amphiphilic polypeptides formed interdigitated planar sheet-like molecular assemblies densely displaying LY (G4). G4 seemed to induce the anti-LY IgM upon immunization to BALB/c mice by only a single administration. However, the amount of anti-LY IgM produced was moderate and significantly less than that induced by two administrations of the other molecular assembly (G1) with the average surface density of LY at a 1/4 of that of G4. Further, the anti-LY IgM produced after two administrations of G4 lowered the avidity more than after one administration.

Glycomapping the fine specificity of monoclonal and polyclonal Lewis antibodies with type-specific Lewis kodecytes and function-spacer-lipid constructs printed on paper.

BACKGROUND: Lewis serologic reagents frequently give inaccurate phenotyping results. Furthermore these serologic reagents are often used in nonserologic assays such as inhibition and immunohistochemistry. In both scenarios knowledge of the fine specificity and cross-reactivity of these reagents will improve the quality of results obtained. STUDY DESIGN AND METHODS: A range of contemporary and historical workshop and developmental Lewis reagents including mouse monoclonal (MoAb) and human and goat polyclonal (PoAb) reagents were evaluated. All were evaluated both against Lewis kodecytes expressing only single Le(a) , Le(b) , ALe(b) , BLe(b) , Le(x) , Le(y) , ALe(y) , or BLe(y) antigens and against the same antigens inkjet printed on a paper-based microplate and analyzed by enzyme immunoassay. Nine clinical samples were also evaluated. A kodecyte antigen dilution sensitivity assay was used to establish the ratio of Le(b) antigen between group A1 /A2 and O RBCs. RESULTS: A continuum of cross-reactivity from Le(x) through to H was observed with MoAbs. All PoAb and few MoAb anti-Le(a) samples and reagents cross-reacted to some degree with Le(b) antigen. Some PoAb and MoAb anti-Le(b) did not cross-react with Le(a) . All polyclonal goat anti-Le(b) reagents showed substantial activity against ALe(b) and BLe(b) , while no MoAb reagent had this activity. A1 RBCs had less than half the Le(b) antigen of A2 /O RBCs. CONCLUSIONS: Substantial cross-reactivity of both MoAbs and PoAbs with related antigens highlights the risks of using serologic reagents in nonserologic assays or against synthetic antigens. The lack of ALe(b) activity in anti-Le(b) MoAbs explains their poor performance against blood group A1 Le(a-b+) phenotypes.

Evaluation of Lewis blood group antigens and secretor status in pemphigus vulgaris.

BACKGROUND: There has not been publication of any previous study about the role of secretory status or Lewis phenotypes in the mechanisms of pemphigus vulgaris (PV). AIM: To evaluate the frequencies of secretory status and Lewis phenotypes in patients with PV compared with healthy controls (HCs) in order determine their roles in this autoimmune disease. METHODS: In total, 50 patients and 100 age- and sex-matched HCs were selected to form the study population, and 2 mL blood were collected from each subject to identify their Lewis phenotype. In subjects with the Le(a-b-) phenotype, saliva was also collected to determine secretor status. RESULTS: The frequency of the nonsecretor (NS) phenotypes Le(a+b-) and Le(a-b-) together was significantly higher in patients than in HCs: 34/50 (68%)vs. 26/100 (26%), respectively (P < 0.001). All the patients and HC subjects with the Le (a-b-) phenotype were found to be NS by haemagglutination inhibition assay of saliva samples. CONCLUSION: Based on our results, it seems that Le/b-negative NS individuals are more susceptible to PV.

A phase II trial with anti-Lewis-Y monoclonal antibody (hu3S193) for the treatment of platinum resistant/refractory ovarian, fallopian tube and primary peritoneal carcinoma.

OBJECTIVES: The primary objective was to evaluate the clinical efficacy of hu3S193, a humanized monoclonal antibody against the Lewis-Y antigen, in patients with platinum resistant/refractory ovarian, fallopian tube and primary peritoneal carcinoma. Secondary objectives were safety and pharmacokinetics. In addition, we sought to determine the potential interaction of clinical benefit and patient characteristics. METHODS: This two-stage, multicenter, single arm, phase II trial enrolled eligible patients to receive hu3S193 weekly at a dose of 20mg/m(2) intravenously for 8 weeks (1 cycle) to a maximum of 3 cycles. Efficacy was measured as clinical benefit rate (objective response or stable disease for at least 24 weeks). RESULTS: 26 of 31 patients were eligible for efficacy analysis. No complete/partial responses were observed. Six patients had stable disease for 24+weeks [clinical benefit rate 23% (95% CI=9.77%-46.71%)]. Median PFS was 8.4 weeks (95% CI=6.0 to 16.1). Median PFS differed between patients with no ascites and no visceral disease and patients with ascites and/or visceral disease [16.1 vs. 8.1 weeks (p=0.0058)]. The most commonly reported treatment-related adverse events were fatigue (19.3%) and nausea (16.2%). Allergic reactions occurred in 6 patients (5 with Grade 1/2; 1 with Grade 3). CONCLUSIONS: Hu3S193 lacked sufficient activity in the first stage of the study to open enrollment to the second stage. However, based on the longer PFS in patients with no ascites and no visceral disease, consolidation strategies in platinum sensitive disease are currently being tested.

Rapid milk group classification by 1H NMR analysis of Le and H epitopes in human milk oligosaccharide donor samples.

Human milk oligosaccharides (HMOs) are a major constituent of human breast milk and play an important role in reducing the risk of infections in infants. The structures of these HMOs show similarities with blood group antigens in protein glycosylation, in particular in relation to fucosylation in Lewis blood group-type epitopes, matching the maternal pattern. Previously, based on the Secretor and Lewis blood group system, four milk groups have been defined, i.e. Lewis-positive Secretors, Lewis-positive non-Secretors, Lewis-negative Secretors and Lewis-negative non-Secretors. Here, a rapid one-dimensional (1)H nuclear magnetic resonance (NMR) analysis method is presented that identifies the presence/absence of (α1-2)-, (α1-3)- and (α1-4)-linked fucose residues in HMO samples, affording the essential information to attribute different HMO samples to a specific milk group. The developed method is based on the NMR structural-reporter-group concept earlier established for glycoprotein glycans. Further evaluation of the data obtained from the analysis of 36 HMO samples shows that within each of the four milk groups the relative levels of the different fucosylation epitopes can greatly vary. The data also allow a separation of the Lewis-positive Secretor milk group into two sub-groups.

Influence of monoclonal anti-Lewis b, anti-H type 1, and anti-sialyl Lewis x antibodies on binding of Helicobacter pylori to MUC1 mucin.

To assess the influence of monoclonal anti-Lewis b, anti-H type 1, and anti-sialyl Lewis x addition on interactions of sugar structures of MUC1 mucin with Helicobacter pylori. The investigations were carried out on gastric juices of 11 patients and 12 H. pylori strains. The levels of Lewis b and sialyl Lewis x antigens on MUC1 were assessed by sandwich ELISA tests. Anti-Lewis b, anti-H type 1 or anti-sialyl Lewis x monoclonal antibodies were added to MUC1 to determine whether the adhesion activities of H. pylori isolates to examined mucin would be affected. Binding of bacteria to MUC1 was assessed by ELISA test. Clear inhibitory effect of examined antibodies was revealed in 6 of 12 examined H. pylori isolates independently on babA2 status. In the rest of strains this effect was negligible. We confirmed participation of Lewis b, H type 1 and also sialyl Lewis x of MUC1 mucin in interactions with H. pylori independently on babA genopositivity. Not full inhibition and a lack of this effect in some strains suggest an existence of other mechanisms of H. pylori adherence to mucin.

Recombinant lectin-like domain of thrombomodulin suppresses vascular inflammation by reducing leukocyte recruitment via interacting with Lewis Y on endothelial cells.

OBJECTIVE: The N-terminal lectin-like domain (domain 1 [D1]) of thrombomodulin (TM) is known to have an anti-inflammatory function. We previously showed that recombinant TM domain 1 (rTMD1) interacts with a carbohydrate molecule, Lewis Y (Le(y)), which is found to be expressed on adhesion molecules and involved in cell adhesion. Here, we tested the effect of rTMD1/Le(y) interaction on leukocyte recruitment in inflammation. APPROACH AND RESULTS: The expression of Le(y) on the surface of human umbilical vein endothelial cells was increased by tumor necrosis factor-α stimulation. Direct binding of rTMD1 to Le(y) on the cell surface was observed. rTMD1 inhibited Le(y)-mediated leukocyte adhesion on the Le(y)-immobilized flow chamber and activated endothelium under a shear flow. The following leukocyte transmigration to endothelium was also reduced by rTMD1 through binding Le(y). In vivo, treatment of rTMD1 reduced leukocyte recruitment to the inflammatory sites in carotid ligation injury and thioglycollate-induced peritonitis. rTMD1 administration in apolipoprotein E-deficient mice effectively suppressed atherosclerotic plaque formation and macrophage infiltration in atherosclerotic lesions. Increased Le(y) expression, as well as administered rTMD1, was observed in inflamed vessels. CONCLUSIONS: rTMD1 suppresses vascular inflammation by inhibiting leukocyte recruitment to endothelium through attenuating Le(y)-mediated adhesion and further protects against atherosclerosis progression. The present study provides a mechanism showing that rTMD1 can inhibit inflammation by binding to its carbohydrate ligand Le(y).

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.

Is there any relationship between Le(b) antigen expression and Helicobacter pylori infection?

INTRODUCTION: Helicobacter pylori infection is one of the main causes of peptic ulcer. There are some blood groups acting as receptors for the pathogen. Based on this view and previous attempts, we tried to examine the relationship between Lewis blood group and H. pylori infection. MATERIALS AND METHOD: Blood and saliva samples were collected from 60 patients with established peptic ulcer induced by H. pylori. Secretory status of each patient was determined by both direct agglutination and saliva tests. RESULTS: Seventy-two percent of the patients were secretor and expressed Lewis B antigen. This rate in control group was 61%. Statistical analysis showed no significant difference between the two groups. CONCLUSION: This study did not find any correlation between Le(b) antigen expression and presence of H. pylori-induced peptic ulcer. It is now recommended that other factors like Lewis(x) and sialyl Lewis(x) should be investigated in binding, colonization and virulence of H. pylori infection in the future.

[Genetic susceptibility to norovirus infection]. / Sensibilité génétique aux infections à norovirus.

Norovirus (NoV) are the most common cause of acute gastroenteritidis in humans worldwide. They are transmitted through consumption of contaminated food, or mostly by direct person-to-person contact. However, susceptibility to NoV infection is variable. NoVs recognize carbohydrate ligand, including A, B, H and Lewis histoblood group antigen (HBGAs) for attachment to human epithelial cells. Synthesis of these HBGAs requires various glycosyltransferase encoded by the ABO, FUT2, FUT3 genes. The presence of distinct carbohydrates structures dependent upon the combined polymorphism at the FUT2, FUT3 and ABO loci influences susceptibility to NoV infection. NoV-glycan interactions studies show that different strains recognize specific HBGAs. Together with herd immunity, HBGAs play a major role in the epidemiology and evolution of NoVs.

Novel functions for glycosyltransferases Jhp0562 and GalT in Lewis antigen synthesis and variation in Helicobacter pylori.

Lewis (Le) antigens are fucosylated oligosaccharides present in the Helicobacter pylori lipopolysaccharide. Expression of these antigens is believed to be important for H. pylori colonization, since Le antigens also are expressed on the gastric epithelia in humans. A galactosyltransferase encoded by ß-(1,3)galT is essential for production of type 1 (Le(a) and Le(b)) antigens. The upstream gene jhp0562, which is present in many but not all H. pylori strains, is homologous to ß-(1,3)galT but is of unknown function. Because H. pylori demonstrates extensive intragenomic recombination, we hypothesized that these two genes could undergo DNA rearrangement. A PCR screen and subsequent sequence analyses revealed that the two genes can recombine at both the 5' and 3' ends. Chimeric ß-(1,3)galT-like alleles can restore function in a ß-(1,3)galT null mutant, but neither native nor recombinant jhp0562 can. Mutagenesis of jhp0562 revealed that it is essential for synthesis of both type 1 and type 2 Le antigens. Transcriptional analyses of both loci showed ß-(1,3)galT expression in all wild-type (WT) and mutant strains tested, whereas jhp0562 was not expressed in jhp0562 null mutants, as expected. Since jhp0562 unexpectedly displayed functions in both type 1 and type 2 Le synthesis, we asked whether galT, part of the type 2 synthesis pathway, had analogous functions in type 1 synthesis. Mutagenesis and complementation analysis confirmed that galT is essential for Le(b) production. In total, these results demonstrate that galT and jhp0562 have functions that cross the expected Le synthesis pathways and that jhp0562 provides a substrate for intragenomic recombination to generate diverse Le synthesis enzymes.

Immunology in the clinic review series; focus on cancer: glycolipids as targets for tumour immunotherapy.

Research into aberrant glycosylation and over-expression of glycolipids on the surface of the majority of cancers, coupled with a knowledge of glycolipids as functional molecules involved in a number of cellular physiological pathways, has provided a novel area of targets for cancer immunotherapy. This has resulted in the development of a number of vaccines and monoclonal antibodies that are showing promising results in recent clinical trials.