Mouse anti-CHST3 monoclonal antibody

Leukocytes express L-selectin ligands critical for leukocyte-leukocyte interactions at sites of inflammation, The predominant leukocyte L-selectin ligand is P-selectin glycoprotein ligand-l (PSGL-1), which displays appropriate sialyl Lewis x (sLe(x))-like carbohydrate determinants for L-selectin recognition, Among the sLe(x)-like determinants expressed by human leukocytes is a unique carbohydrate epitope defined by the HECA-452 mAb. The HECA-452 Ag is a critical component of L-selectin ligands expressed by vascular endothelial cells. However, HECA-452 Ag expression on human leukocyte L-selectin ligands has not been assessed. In this study, the HECA-452 mAb blocked 88-99% of neutrophil rolling on, or attachment to, adherent cells expressing L-selectin in multiple experimental systems. A function-blocking anti-PSGL-1 mAb also inhibited L-selectin binding to neutrophils by 89-98%. In addition, the HECA-452 and anti-PSGL-1 mAbs blocked the majority of P-selectin binding to neutrophils, Western blot analysis revealed that PSGL-1 immunoprecipitated from neutrophils displayed MECA-452 mAb reactive determinants and that PSGL-1 was the predominant scaffold for HECA-452 Ag display. Leukocyte L-selectin ligands also contained sulfated determinants since culturing ligand-bearing cells with NaClO3 abrogated L-selectin binding. Consistent with this, human neutrophils expressed mRNA encoding five different sulfotransferases associated with the generation of selectin ligands: CHST1, CHST2, CHST3, TPST1, and HEC-GlcNAc6ST. Therefore, the HECA-452-defined carbohydrate determinant displayed on PSGL-1 represented the predominant L-selectin and P-selectin ligand expressed by neutrophils.

Rationale: Acute promyelocytic leukemia (APL) is a kind of acute myeloid leukemia, which was characterized by the presence of PML/RARa fusion gene. Mutations in CHST3 have been previously reported to be associated with a rare phenotype of skeleton dysplasia, known as Spondyloepiphyseal dysplasia. Here we reported 1 patient with APL with CHST3 mutations. Patient concerns: An 18-year-old girl was referred to the Hematology Department because of a lasting history (10 days) of repeated fever and bleeding on skin. The girl was of short stature for age and with short fingers. Double nail beds were short with antinail deformity. Diagnoses: She was diagnosed with APL according to the 2016 WHO classification after a MICM analysis (bone marrow morphology [M], immunophenotype [I], cytogenetics [C], and molecular biology [M]). Whole exome sequencing revealed complex heterozygous mutations on CHST3. Further confirmation showed that 1 mutation (c. 155T>G; p. Leu52Arg) was from her father and the other mutation (c. 1414G > A; p. Glu472Lys)was from her mother. Interventions: The patient received Idarubicin (8mg/m2) injection intravenous drip for 3 days based on all-trans retinoic acid and arsenic trioxide induction therapy. Outcomes: The patient died from disseminated intravascular coagulation and multiple organ hemorrhage at 9 days after diagnosis. Lessons: This case describes a patient with APL with complex heterozygous mutations on CHST3. Carbohydrate sulfotransferases were found to play an important role in metastatic spread of tumor cells. Whether the mutation status of CHST3 gene has relationship with APL pathogenesis and prognosis is unknown.