Block synthesis of A tetrasaccharides (types 1, 3, and 4) related to the human ABO blood group system

CLINICAL, HEMATOLOGICAL CHARACTERIZATION AND POLYMORPHISM OF ABO AND Rh BLOOD GROUP SYSTEMS IN PLASMA CELL MYELOMA PATIENTS

Objective to study the peculiarities of clinical characteristics and polymorphism of ABO and Rh blood group systemsin relation to the natural history of plasma cell myeloma in the ChNPP accident survivors.

MATERIALS AND METHODS

Peculiarities of the disease natural history were reviewed in the 111 plasma cell myeloma(PCM) patients receiving medical management at the Department of Radiation Oncohematology of the NRCRM dur-ing 2010-2017. Principal clinical and laboratory characteristics of PCM, namely the values/levels of LDH, β2-mic-roglobulin, albumin, serum calcium, urea, creatinine and hemoglobin were assessed, taking into account the gender,radiation history (ChNPP accident clean-up workers, evacuees from areas of obligatory resettlement, inhabitants ofcontaminated territories, and the comparison group) and the PCM stage codenamed by Durie-Salmon et al. (1975)and the ISS (1985) classifications. Distribution of polymorphic variants on ABO and Rh blood systems was studiedin the 106 PCM patients.

RESULTS

It was found that the level of β2-micro-globulin and calcium was increased significantly in male (p = 0.02and p = 0.04, respectively), whereas serum urea content was elevated in female (p = 0.04) PCM patients featuring acompromised radiation anamnesis in comparison to non-irradiated patients. Some probable differences were foundfor urea level (F = 3.58, p = 0.05) and serum albumin (F = 4.00, p = 0.05) in the examined group of PCM patients.Probable (p < 0.05) incidence increase of the B phenotype was established as a predictor of complicated natural his-tory of PCM with abnormal genetic equilibrium resulted from the increased incidence of IB allele in chronic renal fail-ure (CRF) patients. Significant (p < 0.05) prolongation of the remission period upon a standard PCT application wasfound in PCM patients being the A phenotype carriers having a preserved gene and phenotypic equilibrium comparedwith carriers of O and B phenotypes.

CONCLUSIONS

Clinical and hematological parameters are different in PCM patients survived after the ChNPP accidentand those with favorable radiation history. Distribution of polymorphic variants of ABO antigenic structures inpatients with complicated natural history of the disease is also different, that can be a background for predictingthe effectiveness of treatment. Further research is required in this field.

Application of a Janus aglycon with dual function in benzyl-free synthesis of spacer-armed oligosaccharide fragments of polysaccharides from rhizobacterium Azospirillum brasilense sp7

Both protective and pre-spacer features of 4-(2-chloroethoxy)phenyl (CEP) aglycon, which belong to the class of Janus aglycons, were engaged in a benzyl-free synthesis of oligosaccharide fragments of polysaccharides from rhizobacterium Azospirillum brasilense sp7. Introduction of α-1,4-linked L-fucose residue was performed using 3,4-di-O-benzoyl-2-O-triisopropylsilyl-α-L-fucopyranosyl N-phenyltrifluoroacetimidate in excellent stereoselectivity and high yields. The obtained deprotected di-, tri- and tetrasaccharides contain 4-(2-azidoethoxy)phenyl (AEP) spacer aglycon, which allows straightforward preparation of neoglycoconjugates that will be used for the study of the role of lipopolysaccharide of rhizobacterium A. brasilense sp7 in plant-microbe symbiosis. The intermediate protected oligosaccharide building blocks with cleavable CEP/AEP aglycons have a strong potential for further application in the synthesis of more complex oligosaccharides.

Production of human blood group B antigen epitope conjugated protein in Escherichia coli and utilization of the adsorption blood group B antibody

Background

In the process of ABO-incompatible (ABOi) organ transplantation, removal of anti-A and/or B antibodies from blood plasma is a promising method to overcome hyperacute rejection and allograft loss caused by the immune response between anti-A and/or B antibodies and the A and/or B antigens in the recipient. Although there are commercial columns to do this work, the application is still limited because of the high production cost.

Results

In this study, the PglB glycosylation pathway from Campylobacter jejuni was exploited to produce glycoprotein conjugated with Escherichia coli O86:B7 O-antigen, which bears the blood group B antigen epitope to absorb blood group B antibody in blood. The titers of blood group B antibody were reduced to a safe level without changing the clotting function of plasma after glycoprotein absorption of B antibodies in the plasma.

Conclusions

We developed a feasible strategy for the specific adsorption/removal of blood group antibodies. This method will be useful in ABOi organ transplantation and universal blood transfusion.

Electronic supplementary material

The online version of this article (doi:10.1186/s12934-016-0538-z) contains supplementary material, which is available to authorized users.

Rapid synthesis of linear homologous oligoarabinofuranosides related to mycobacterial lipoarabinomannan and a neoglycoconjugate thereof

Rapid and simple synthesis of oligosaccharides related to one of the terminal motifs of mycobacterial lipoarabinomannan is described. An array of homologous linear α(1 → 5)-linked oligoarabinofuranosides with 4-(2-chloroethoxy)phenyl aglycon and selectively unprotected 5-OH group at the non-reducing end was obtained by oligomerization of 3-O-benzoyl β-D-arabinofuranose 1,2,5-orthobenzoate. Subsequent introduction of β(1 → 2)-linked arabinofuranose disaccharide moiety by step-wise glycosylation furnished the target oligosaccharides which were conjugated with bovine serum albumin.

A guide into glycosciences: How chemistry, biochemistry and biology cooperate to crack the sugar code

BACKGROUND

The most demanding challenge in research on molecular aspects within the flow of biological information is posed by the complex carbohydrates (glycan part of cellular glycoconjugates). How the 'message' encoded in carbohydrate 'letters' is 'read' and 'translated' can only be unraveled by interdisciplinary efforts.

SCOPE OF REVIEW

This review provides a didactic step-by-step survey of the concept of the sugar code and the way strategic combination of experimental approaches characterizes structure-function relationships, with resources for teaching.

MAJOR CONCLUSIONS

The unsurpassed coding capacity of glycans is an ideal platform for generating a broad range of molecular 'messages'. Structural and functional analyses of complex carbohydrates have been made possible by advances in chemical synthesis, rendering production of oligosaccharides, glycoclusters and neoglycoconjugates possible. This availability facilitates to test the glycans as ligands for natural sugar receptors (lectins). Their interaction is a means to turn sugar-encoded information into cellular effects. Glycan/lectin structures and their spatial modes of presentation underlie the exquisite specificity of the endogenous lectins in counterreceptor selection, that is, to home in on certain cellular glycoproteins or glycolipids.

GENERAL SIGNIFICANCE

Understanding how sugar-encoded 'messages' are 'read' and 'translated' by lectins provides insights into fundamental mechanisms of life, with potential for medical applications.

A new chemical approach to human ABO histo-blood group type 2 antigens

A new chemical approach to synthesizing human ABO histo-blood type 2 antigenic determinants was developed. N-Phthaloyl-protected lactosaminyl thioglycoside derived from lactulose via the Heyns rearrangement was employed to obtain a type 2 core disaccharide. Use of this scheme lowered the overall number of reaction steps. Stereoselective construction of the α-galactosaminide/galactoside found in A- and B-antigens, respectively, was achieved by using a unique di-tert-butylsilylene-directed α-glycosylation method. The proposed synthetic scheme provides an alternative to existing procedures for preparing ABO blood group antigens.