Changes in Glycanic Determinants of Lymphocytes Membranes in Peripheral Blood in Patients with B-Cell Chronic Lymphocytic Leukemia under Antitumor Therapy

The purpose of the study was to study the nature of changes in the exposure of surface glycans of peripheral blood lymphocytes in patients with B-cell chronic lymphocytic leukemia under conditions of antitumor therapy. Materials and methods. We studied the features of exposure of surface glycotopes of peripheral blood lymphocytes in patients with B-cell chronic lymphocytic leukemia under conditions of antitumor therapy using a set of seven lectins labeled with FITC and monoclonal antibodies to Tn-antigen- FITC for the detection of Tn antigen and CD43 exposure on blood lymphocytes. Cytostatic therapy included cyclophosphamide, vincristine (oncovin), prednisolone. Data were recorded on a Beckman Coulter EPICS flow cytometer. The results were processed using FCS3 Express. Results and discussion. The number of lymphocytes of healthy donors with a positive reaction to ConA, PHA-L, SNA, MAA-II and α1-acid glycoprotein amounted to 16.0±3.0%, 23.0±2.3%, 15.0±1.5%, 25.0±1.8% and 15.0±1.3%, respectively. The number of LABA-, UEA I-positive lymphocytes was 0.90±0.03% and 2.9±0.2%, respectively, and there was no binding to antibodies to Tn- and CD43-antigens. In the blood of patients with chronic lymphocytic leukemia, the level of ConA-, SNA- and MAA-II-positive lymphocytes increased relative to control by 2.2, 3.7 and 2.6 times, respectively. The number of LABA- and UEA I-positive lymphocytes in patients with chronic lymphocytic leukemia increased by 11 (p <0.01) and 23 (p <0.001) times and amounted to 10.5±0.5% and 67.5±5.5% respectively. The number of lymphocytes with CD43 antigen on their surface increased by 72 times, and the Tn antigen increased by 80 times. Cytostatic therapy reduced the level of LABA- and UEA I-positive lymphocytes by almost half, and MAA II-positive cells and lymphocytes interacting with antibodies to CD43 and Tn antigen by a third. The level of PHA-L-positive lymphocytes in the blood of chronic lymphocytic leukemia patients after undergoing alkylating therapy increased by 18.0±2.0% and almost did not differ from those obtained in the control group. Conclusion. 1. In chronic lymphocytic leukemia patients, the structure of glycoconjugates in peripheral blood lymphocytes changes, manifested in increased exposure of L-fucose, α-mannose and N-acetylneuraminic acid, which is confirmed by a significant increase in relation to the control of the number of ConA-, SNA-, MAA-II-, LABA I-positive cells. 2. Patients with chronic lymphocytic leukemia showed a significant increase in the number of lymphocytes, in which the markers of carcinogenesis CD43 and Tn antigens were found. 3. Cytostatic therapy significantly reduced the level of LABA-, UEA I- and MAA II-positive cells, as well as partially Tn- and CD43-antigen-positive lymphocytes, which indicates its positive effect on the treatment of chronic lymphocytic leukemia

Large-scale preparation of sialyl-Tn antigen-containing peptides from mucin-like glycoproteins in boar seminal gel

Sialyl-Tn antigen, a tumor antigen, is a valuable ligand for the purification of proteins that specifically bind to it. Here, we developed a new method for the preparation of large amounts of sialyl-Tn antigen-containing peptides from an unused resource, boar seminal gel. The glycopeptides were prepared from the actinase E digests by a combination of gel filtration and hydrophilic partitioning.

Efficient and Reproducible Synthesis of an Fmoc-protected Tn Antigen

The total synthesis of the Thomsen-nouveau (Tn) antigen, a tumour-associated O-linked mucin glycopeptide, was achieved through a concise route. The key glycosylation step proved challenging to reproduce from the literature precedents and was most reliably accomplished using a palladium-catalyzed coupling between the glycosyl donor and Fmoc-functionalized serine acceptor to form the target in moderate yields. This is, to the best of our knowledge, the shortest synthesis reported from galactose for preparing this essential building block for large-scale solid phase peptide synthesis.

Efficient and Reproducible Synthesis of an Fmoc-protected Tn Antigen

The total synthesis of the Thomsen-nouveau (Tn) antigen, a tumour-associated O-linked mucin glycopeptide, was achieved through a concise route. The key glycosylation step proved challenging to reproduce from the literature precedents and was most reliably accomplished using a palladium-catalyzed coupling between the glycosyl donor and Fmoc-functionalized serine acceptor to form the target in moderate yields. This is, to the best of our knowledge, the shortest synthesis reported from galactose for preparing this essential building block for large-scale solid phase peptide synthesis.