Diphtheria Toxin/Human B-Cell Activating Factor Fusion Protein Kills Human Acute Lymphoblastic Leukemia BALL-1 Cells: An Experimental Study

Objective： This study aimed to express a fusion protein of diphtheria toxin and human B cell-activating factor （DT388sBAFF） in Escherichia coli （E. coli） and investigate its activity in human B-lineage acute lymphoblastic leukemia 1 cells （BALL-1）. Methods： A fragment of DT388sBAFF fusion gene was separated from plasmid pUC57-DT388sBAFF digested with Nde I and Xho I, and inserted into the expression vector pcold II digested with the same enzymes. Recombinants were screened by the colony polymerase chain reaction （PCR） and restriction map. The recombinant expression vector was transformed into BL21 and its expression was induced by isopropyl β-D-1-thiogalactopyranoside （IPTG）. The recombinant protein was identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis （SDS-PAGE） and Western blot, and then purified by Ni2＋-NTA affinity chromatography. The expression level of B cell-activating factor receptor （BAFF-R） on BALL-1 cells was assessed by real-time PCR. The receptor binding capacity of recombinant protein was determined by cell fluorescent assay. The specific cytotoxicity of recombinant protein on BALL-1 cells was detected by 3-（4,5-dimethylthiazolyl-2）-2,5-diphenyltetrazolium bromide （MTT） assay. Results： The expression level of recombinant protein was 50% of total bacterial proteins in E. coli, and the recombinant protein could bind to BAFF-R-positive BALL-1 cells and thereby produce a cytotoxic effect on the cells. Conclusion： The fusion protein expression vector DT388sBAFF was successfully constructed and the recombinant protein with selective cytotoxicity against BALL-1 cells was obtained, providing foundation for further study of the therapy of human B-lineage acute lymphoblastic leukemia.

Outcomes of Preimplantation Genetic Diagnosis Cycles by Fluorescent In situ Hybridization of Infertile Males with Nonmosaic 47,XYY Syndrome

Background： The 47,XYY syndrome could result in fertility problems. However, seldom studies reported comprehensive researches on the embryonic development and pregnancy outcomes of these patients. This study aimed to evaluate the clinical outcomes of nonmosaic 47,XYY patients performed with fluorescent in situ hybridization （FISH） and preimplantation genetic diagnosis （PGD） treatment. Methods： This was a retrospective study. Between January 2012 and May 2017, 51 infertile males with nonmosaic 47,XYY syndrome underwent FISH-PGD were included in the study. According to sex chromosomal FISH results, embryos were classified as normal signal, no nuclei fixed, no signal in fixed nuclei, suspensive signal, and abnormal signal groups, respectively. The incidence of each group, the fixation rate, and hybridization rate were calculated. Embryonic development and pregnancy outcomes were also analyzed. The measurement data were analyzed with Student＇s t-test. The comparison of categorical data was analyzed with the Chi-square test and Fisher＇s exact test when expected cell count was 〈5. Results： The 53 PGD cycles with 433 embryos were analyzed. The fixation rate was 89.6%, while the hybridization rate was 96.4%. There were 283 embryos with two sex chromosomal signals with clear diagnosis （65.4%）. The numbers of no nuclei fixed, no signal in fixed nuclei, suspensive signal, and abnormal signal groups were 45 （10.4%）, 14 （3.2%）, 24 （5.5%）, and 67 （15.5%）, respectively. Embryos with abnormal signals were abandoned. The number of good-quality embryos was 210 （57.4%）, including implanted embryos on day 4/day 5 a.ld cryopreserved. The rates of good-quality embryos in the no nuclei fixed （22.2%）, no signal in fixed nuclei （28.6%）, and suspensive signal groups （33.3%） were comparable （P 〉 0.05）, and were significantly lower than the normal signal group （66.4%, P 〈 0.001 ）. The clinical pregnancy rates of fresh and frozen embryos transferred cycles were 70.6% and 85.7%, respectively. Conclusions： Among embryos with a clear diagnosis of sex chromosome, about one-fifth showed abnormal signals. Embryos with two sex chromosomal signals are more likely to develop into good-quality ones. The application of the PGD by FISH may help to improve the clinical outcomes.

Outcomes of 13 ICSI-PGD cycles with ejaculated spermatozoa in patients with Klinefelter syndrome

Dear Editor, Klinefelter syndrome （KS） is the most frequent genetic cause of infertility in men. Paternity can be achieved through intracytoplasmic sperm injection （ICSI） with spermatozoa recovered from ejaculated semen if exist, or testes with testicular sperm extraction （TESE）.