Ex vivo maintainance of human stem cells is crucial for many clinical applications. Current culture conditions provide some level support but cytokines induce most quiescent stem cells to proliferate and differentiate. Better control of primitive cells is needed to extend the time and range of manipulation of such cells. A recently identified plant lectin Flt3 receptor-interacting lectin (FRIL) present may a special ability to preserve primitive CB progenitors for extended periods in culture without exogenous cytokines. But the mechanisms of FRIL preserving quiescent primitive cells are still unknown. Recently a novel protein HTm4 and its alternatively spliced variant HTm4S, which serve as hematopoietic cell cycle regulators, have been identified. In this report we studied the effect of FRIL on the in vitro maintenance of quiescent human cord blood stem cells and the expression of the novel hematopoietic cell cycle regulator HTm4 and HTm4S in progenitor cells cultured in FRIL. We analyzed the proliferation and the HPP-CFC proportion of CD34(+) cells treated with FRIL. The human HTm4 and HTm4S mRNA expression was detected by semi-quantitative RT-PCR, and the cell cycle status of CB CD34(+) cells was analyzed by FACS. The results showed that incubation of CD34(+) cells in FRIL resulted in a low proliferation of progenitor cells and fewer cycling cells, but FRIL selectively maintained a higher number of primitive cells with proliferative potential in suspension culture. CB CD34(+) cells cultured in FRIL showed significant diversity in the expression of HTm4 and HTm4S during 0~14 d. On d 0, HTm4 was detected at high level, downregulated on d 1, but upregulated during d 3 to d 14, and reaching the highest level on d 7. But the expression levels of HTm4S changed little in the cells cultured in FRIL except the obviously increased expression on d 7. Exogenous expression showed that HTm4 was localized around the karyon while HTm4S scatted in the cytoplasm, respectively, which may be responsible for their difference in function. Thus, FRIL can preserve quiescent primitive CD34(+), and FRIL's ability to preserve quiescent primitive cells in a reversible manner may significantly expand the time and range of ex vivo manipulations of human stem cells for clinical applications. In other words, HTm4 and HTm4S may play a crucial role in the cell cycle modulation of CD34(+) progenitor cells maintained with FRIL in vitro.
Antigens, CD20 ; biosynthesis ; genetics ; Antigens, CD34 ; metabolism ; Cell Cycle ; Cell Cycle Proteins ; biosynthesis ; genetics ; Cell Separation ; Cells, Cultured ; Fetal Blood ; cytology ; Hematopoietic Stem Cells ; cytology ; Humans ; Mannose-Binding Lectins ; pharmacology ; Membrane Proteins ; biosynthesis ; genetics ; Plant Lectins ; pharmacology

A successful transplantation, across a positive crossmatch barrier, is one of the most persistent long- standing problems in the field of kidney transplant medicine. The aim of this study was to describe seven consecutive living renal transplantations in recipients with positive crossmatch for donors or positive for donor specific antibodies (DSAs). A preconditioning regimen including plasmapheresis and intravenous immunoglobulin was delivered three times a week until the crossmatch and/ or DSAs became negative. Mycophenolate mofetil and tacrolimus were started two days before the plasmapheresis. The protocol was modified to include administration of anti-CD 20 antibody (rituximab, 375 mg/m(2)) from the patient number 3 through the patient number 7. All seven patients achieved negative conversion of the crossmatch or DSAs, and the kidney transplantations were successfully performed in all cases. Acute cellular rejection occurred in two patients, which were subclinical and controlled with high dose steroid treatment. Antibody-mediated rejection occurred in one patient, which was easily reversed with plasmapheresis. All recipients attained normal graft function during the 7-24 months of follow up. Our study suggests that sensitized patients can be transplanted successfully with desensitization pretreatment.
Adult ; Antibodies, Monoclonal/pharmacology ; Antigens, CD20/biosynthesis ; Biopsy ; Female ; Graft Rejection ; Graft Survival ; Histocompatibility Testing/methods ; Humans ; Immunoglobulins/chemistry ; Kidney Transplantation/*methods ; Male ; Middle Aged ; Plasmapheresis ; Transplantation Conditioning

Several studies have demonstrated the role of 4-1BBL in T cell activation. Furthermore, enhanced 4-1BB/4-1BBL interaction has been shown to amplify T-cell-mediated antitumor immunity in several mouse models. However, when applied in humans, it was difficult to generate sufficient T cells ex vivo and whole cell vaccines to transfer back into patients. To overcome this difficulty, we have focused on producing the human 4-1BBL extracellular domain/anti-CD20 Fab' fusion protein. In this report, PCR and overlap PCR were used to construct the human 4-1BBL extracellular domain/anti-CD20 Fab' expression vector. DNA sequence was analyzed by the Terminus of Dideoxy Nucleotide. The product was purified by affinity chromatography and analyzed by SDS-PAGE and HPLC; its antigen binding activity was examined by rosetting assay. The data of DNA sequence showed that the human 4-1BBL extracellular domain/anti-CD20 Fab' fusion protein was corrected. The fusion protein was recovered in high yield (up to 200 microg/mL) after E-taq purification. The fusion protein was capable of simultaneous binding to stimulated Jurkat cells and Raji cells as shown by cellular rosetting. In conclusion, the human 4-1BBL extracellular domain/anti-CD20 Fab' fusion protein was induced to express in E. coli 16C9. The results of some biological activity experiments indicated that the fusion protein could bind to stimulated Jurkat cells and Raji cells. Furthermore, 4-1BBL-negative tumors can be converted into 4-1BBL-positive tumors by the fusion protein without the need for 4-1BBL gene transfer to the malignant cells.
4-1BB Ligand ; biosynthesis ; genetics ; Antibodies, Bispecific ; immunology ; Antigens, CD20 ; immunology ; Humans ; Immunoglobulin Fab Fragments ; biosynthesis ; genetics ; Immunotherapy ; methods ; Lymphoma, Non-Hodgkin ; therapy ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; immunology

The synthetic gene with 1640bp encoding for the anti-CD3/anti-CD20 bispecific single-chain antibody was designed and obtained by SOE (splicing by overlap extension) PCR. The cDNA was cloned into Flp-In expression vector pcDNA5/FRT and transfeced into Flp-In CHO cells to generate a stable expression cell line with a capacity for expressing anti-CD3/anti-CD20 bispecific single-chain antibody at 300 microg/L. The protein, which had a molecular weight of about 70 kD,was purified by Ni-NTA affinity chromatography and identified by SDS-PAGE and Western-blot analysis. Immunofluorescence assay and cellular rosetting showed that it can react specifically on Jurkat (CD3+) and Ramous (CD20+) cells. The lysis of human PBL against CD20-positive lymphoma Ramous cells in the presence of the anti-CD3/anti-CD20 bispecific single-chain antibody can observed by microscope. All these results would lighten the further study of its biological functions in vitro and in vivo.
Animals ; Antibodies, Bispecific ; biosynthesis ; genetics ; immunology ; Antibodies, Monoclonal ; immunology ; Antigens, CD20 ; immunology ; CD3 Complex ; immunology ; CHO Cells ; Cricetinae ; Cricetulus ; Humans ; Immunoglobulin Variable Region ; biosynthesis ; genetics ; immunology ; Lymphoma, B-Cell ; metabolism ; Recombinant Proteins ; Transfection ; Tumor Cells, Cultured

The term "chordoid meningioma" means meningioma, which is pathologically similar to chordoma, and previously reported that rarely associated with microcytic anemia and/or dysgammaglobulinemia especially in pediatric population. We present a case of this rare variant, which comprises less than 0.5% of all meningiomas. A 33-yr-old man visited our hospital, complaining visual field defect worsening over 7 yr. Neurological examination showed left homonymous hemianopsia. The brain magnetic resonance imaging revealed well enhancing right temporo-occipital mass with cystic portion. Histopathologic findings of resected tumor were compatible with chordoid meningioma which included trabeculae of eosinophilic, vacuolated cells in a myxoid matrix with prominent lymphoplasmacellular infiltration. The neoplastic cells were positive for vimentin and epithelial membrane antigen and negative for glial fibrillary acidic protein and cytokeratin. This is an adult case of chordoid meningioma without anemia or dysgammaglobulinemia.
Adult ; Antigens, CD20/biosynthesis ; Antigens, CD3/biosynthesis ; B-Lymphocytes/pathology ; Brain/pathology ; Brain Neoplasms/*diagnosis/*pathology ; CA-15-3 Antigen/biosynthesis ; Chordoma/*diagnosis/*pathology ; Human ; Magnetic Resonance Imaging ; Male ; Meningeal Neoplasms/*diagnosis ; Meningioma/*diagnosis ; T-Lymphocytes/pathology ; Vimentin/biosynthesis ; Visual Fields

The use of tumor antigen specific antibody for the delivery of therapeutic agents offers the possibility of targeting therapy with reduced toxicity to normal tissues compared to conventional treatments. In previous work, the human-mouse chimeric antibody fragment Fab' directed against CD20 was constructed from the new anti-CD20 antibody HI47 (a mouse IgG3, K). The chimeric antibody fragment Fab' could reduce its antigenicity, but the yield, quality and affinity of chimeric antibody fragment Fab' restrict its use. To improve affinity of chimeric antibody fragment Fab', a new phasmid pYZcpp3, which expresses chimeric antibody fragment F(ab')2, was constructed by adding a sequence encoding a small peptide, (CPP)3, to C-terminus of heavy chain constant region of chimeric antibody fragment Fab'. Using the pYZcpp3 to transform E. coli. 16c9, the genetically engineered bacteria 10916# was obtained. 10916# can secret the soluble chimeric antibody fragment Fab' and F(ab')2 into periplasmic. The yield was up to 360 mg/L with the percent of F(ab')2 up to 45% in 19L fermentor by the high density fermentation technology. Without denaturation and renaturation, the F(ab')2 has possessed the native three-dimensional structure. The purity of F(ab')2 was more than 90% after the purification of protein G affinity chromatography and S200 size exclusion chromatography. The F(ab')2 could distinguish and bind to Raji cells (CD20+) by FACS. F(ab')2 could inhibit the proliferation of Raji cells in vitro by MTT, IC50 was 22.8 microg/mL. HI47 and its chimeric fragments F(ab')2 induced a significant level of apoptosis (23.5%, 20.8%, respectively), independent of any cross-linking agents, in Raji cells after 24 h incubation. The chimeric antibody fragment F(ab')2 directed against CD20 is possible to apply to tumor therapy in clinic in the future.
Antigens, CD20 ; immunology ; Apoptosis ; Escherichia coli ; genetics ; Fermentation ; Humans ; Immunoglobulin Fab Fragments ; chemistry ; genetics ; isolation & purification ; therapeutic use ; Lymphoma, B-Cell ; therapy ; Plasmids ; Recombinant Fusion Proteins ; biosynthesis ; isolation & purification ; therapeutic use

Intravenous immunoglobulin (IVIG) and/or plasmapheresis (PP) are effective in preventing antibody-mediated rejection (AMR) of kidney allografts, but AMR is still a problem. This study reports our experience in living donor renal transplantation in highly sensitized patients. Ten patients with positive crossmatch tests or high levels of panel-reactive antibody (PRA) were included. Eight patients were desensitized with pretransplant PP and low dose IVIG, and two were additionally treated with rituximab. Allograft function, number of acute rejection (AR) episodes, protocol biopsy findings, and the presence of donor-specific antibody (DSA) were evaluated. With PP/IVIG, six out of eight patients showed good graft function without AR episodes. Protocol biopsies revealed no evidence of tissue injury or C4d deposits. Of two patients with AR, one was successfully treated with PP/IVIG, but the other lost graft function due to de novo production of DSA. Thereafter, rituximab was added to PP/IVIG in two cases. Rituximab gradually decreased PRA levels and the percentage of peripheral CD20+ cells. DSA was undetectable and protocol biopsy showed no C4d deposits. The graft function was stable and there were no AR episodes. Conclusively, desensitization using PP/IVIG with or without rituximab increases the likelihood of successful living donor renal transplantation in sensitized recipients.
Adult ; Antibodies, Monoclonal/therapeutic use ; Antigens, CD20/biosynthesis ; Female ; Humans ; Immunoglobulins/metabolism ; Immunophenotyping ; Immunosuppressive Agents/therapeutic use ; Isoantibodies/chemistry ; Kidney Failure, Chronic/therapy ; Kidney Transplantation/*methods ; Lymphocytes/metabolism ; Male ; Middle Aged ; Retrospective Studies

In order to provide the evidences for CD19 as a better antibody targeting molecule for B lineage acute leukemias than CD20 through the multi-parameter flow-cytometry analysis of leukemia cells, the samples from 321 patients with acute leukemia (AL) were immunophenotyped by multi-color flow cytometry and CD45/SSC gating strategy followed by the analysis of CD19 and CD20 expression. The results showed that the positive rate of CD19 (115/116, 99.1%) in 116 cases with B lineage acute lymphoblastic leukemia (B lineage ALL) was significantly higher than that of CD20 (33/116, 28.4%) (P < 0.01); in 17 patients with B lineage/Myeloid (B/My) acute mixed lineage leukemia (AMLL), the former positive rate (17/17, 100%) was also higher than the latter (5/17, 29.4%) (P < 0.01). Both of the two antigens were negative in 29 patients with acute T lymphoblastic leukemia and 7 patients with T/My AMLL. The positive rates of CD19 and CD20 in 152 patients with acute myeloid leukemia (AML) were 7.2% and 2.0%, respectively. The difference of the fluorescence intensity between the two antigens on the cells from each patient with B lineage ALL or B/My AMLL was statistically significant (t = 20.68, P < 0.001). The specificity of CD19 and CD20 in B lymphocytic lineage was 92.3% (132/143) and 92.7% (38/41), respectively, while the sensitivity was 99.2% (132/133) and 28.6% (38/133), respectively, the former sensitivity was significantly higher than the latter (chi(2) = 144.018, P = 0.001). It is concluded that CD19 continuously and steadily express on almost all subtypes of B lineage leukemic cells with homogeneous pattern while only a small number of leukemias express CD20. Both the specificity and sensitivity of CD19 were very high with a much broader reaction pattern than that of CD20 on this group of diseases. These indicate that CD19 may be a better antibody targeting molecule than CD20 for patients with B-lineage acute leukemia.
Acute Disease ; Adolescent ; Adult ; Antigens, CD19 ; biosynthesis ; Antigens, CD20 ; biosynthesis ; Bone Marrow Cells ; immunology ; metabolism ; pathology ; Cell Lineage ; Child ; Child, Preschool ; Female ; Flow Cytometry ; Humans ; Immunophenotyping ; Infant ; Leukemia ; blood ; immunology ; pathology ; Leukocytes, Mononuclear ; immunology ; metabolism ; pathology ; Male ; Middle Aged ; Tumor Cells, Cultured