Specificity analysis of blood group Lewis-y (Le(y)) antibodies generatedagainst synthetic and natural Le(y) determinants.

Abstract

Le(y)-reactive monoclonal antibodies (mAbs) were generated in mice by immunization with synthetic Le(y) neoglycoproteins or with Le(y)-expressing cells. Serological analysis indicated that mAbs raised against synthetic Le(y) (i) reacted strongly with synthetic Le(y) but poorly with natural Le(y), (ii) cross-reacted with Le(x) or H-type 2 structures, and (iii) were IgG1, IgG2a, or IgG2b. mAbs raised against Le(y)-expressing cells (i) reacted with both synthetic Le(y) and natural Le(y), (ii) were of two types: cross-reactive with Le(x) or H-type 2 structures or specific for Le(y), and (iii) were IgM or IgG3. One of the mAbs raised against natural Le(y), mAb 3S193 (IgG3), showed high specificity for Le(y) in ELISA tests with synthetic Le(y) and Le(y) containing glycoproteins and glycolipids; it also reacted strongly in rosetting assays and cytotoxic tests with Le(y)-expressing cells. mAb 3S193 did not lyse O, A, AB, and B human erythrocytes in the presence of human complement. In flow cytometry, there was weak reactivity with granulocytes, a reactivity also observed with two previously described highly specific Le(y) mouse mAbs--BR55-2 (IgG3) and B3 (IgG1). A humanized version of mAb 3S193 has been constructed, and the specificity pattern and reactivity for Le(y) remain very similar to mouse mAb 3S193.

Three‐dimensional structures of carbohydrate determinants of Lewis system antigens: Implications for effective antibody targeting of cancer

“…45 We determined the 1.9 Å resolution structure of the Fab of a humanized antibody (hu3S193) in complex with the synthetic Le y tetrasaccharide. 46 The murine BR96 45,47 and 3S193 (hu3S193 was derived from this antibody) 8,48 were independently generated by standard hybridoma techniques using BALB/c mice that had been immunized with Le y -positive human carcinoma cell lines. Another monoclonal antibody, 291-2G3-A, specific for the Le x antigen, was generated from mice infected with the parasite Schistosoma mansoni, which displays high levels of Le x as well as Le y -like carbohydrate determinants among many other N-and O-linked and glycolipid structures, at various stages of its life cycle.…”

Phase I Dose Escalation Study with the Lewis Y Carbohydrate Specific Humanized Antibody IGN311

“…Recently, a Phase I biodistribution and pharmacokinetic trial with the humanized mAb Hu3s193 in patients with LeY positive, advanced epithelial cancer has demonstrated selective targeting of tumors with no evidence of any consistent normal tissue uptake [26]. Another promising humanized LeY specific mAb is the hABL364-designated IGN311-that is the humanized version of the murine mAb BR55-2 [1,6,[15][16][17]. During humanization, the affinity to the target cells and the effector functions were optimized by molecular modeling [23].…”

“…Because LeY represents an attractive target for immune therapy, a variety of murine mAbs has been generated against this carbohydrate antigen and their anti-tumor activities have been explored and have demonstrated anti-tumor activity in tumor cell models in vitro, animal models and clinical studies [1,2,6,[15][16][17][18][19][20][21][22].…”

Gene-modified T cells as immunotherapy for multiple myeloma and acute myeloid leukemia expressing the Lewis Y antigen

“…15 In this study, we demonstrate that the expression of Le Y is not restricted to epithelial tumors but is also found on AML and MM. Given the previously documented expression of Le Y on mature neutrophils, 24,29 the finding that it is also expressed on AML blasts is not entirely surprising. In contrast, the expression on plasma cells was rather Y as a target antigen for the treatment of MM and AML.…”