Assessment of monoclonality of cell bank for recombinant biologics production / 药学学报

To ensure the consistency of quality in recombinant protein production, the cell bank for biologics should be derived from a single clone. A number of techniques have been used for cloning and assurance from the cellular pool after transfection with a target gene. Here, using CHO cell as an example, we summarize the knowledge and understanding of monoclonality of production cell bank from both industries and regulatory authorities, and propose general considerations on the requirements of monoclonality for clinical trial application and new drug application based on current techniques. Furthermore, we suggest quality control strategies and assessment methods for those cell banks from non-single clones.

Detection Limit of Monoclonal B-Cells Using Multiplex PCR and Laser-Induced Fluorescence Capillary Electrophoresis

BACKGROUND: The identification of monoclonality has been widely used for making diagnoses of lymphoproliferative lesions. Awareness of the sensitivity and detection limit of the technique used would be important for the data to be convincing. METHODS: We investigated the minimum requirement of cells and sensitivity of gel electrophoresis (GE) and laser-induced fluorescence capillary electrophoresis (LFCE) for identifying IgH gene rearrangement using BIOMED-2 protocols. DNA extracted from Raji cells were diluted serially with peripheral blood mononuclear cells (PBMNCs) DNA. DNA from mixtures of diffuse large B-cell lymphoma (DLBCL) and reactive lymph nodes were also serially diluted. RESULTS: For Raji cells, the detection limit was 62 and 16 cell-equivalents for GE and LFCE, respectively. In the condition with PBMNCs mixture, 2.5% and 1.25% of clonal cells was the minimum requirement for GE and LFCE, respectively. In 23% of DLBCL cells in tissue section, the detection limit was 120 and 12 cell-equivalents for GE and LFCE, respectively. In 3.2% of DLBCL cells, that was 1,200 and 120 cell-equivalents for GE and LFCE, respectively. CONCLUSIONS: These results show that LFCE method is more sensitive than GE and the sensitivity of clonality detection can be influenced by the amount of admixed normal lymphoid cells.

Kappa Chain Monoclonal Primary Cutaneous Plasmacytoma / 대한피부과학회지

Primary cutaneous plasmacytoma is a rare type of cutaneous B-cell lymphoma that arises primarily in the skin, and this is derived from clonally expanded plasma cells with various degrees of maturation and atypia. A 72-year-old man had an asymptomatic, solitary reddish to violaceous nodule on the back for about 4 months. The histologic finding of the skin biopsy specimen demonstrated an infiltration of variably matured plasma cells in the dermis, and these cells showed a monotypic expression of immunoglobulin kappa chains on immunohistochemical staining. Staging investigations excluded any extracutaneous manifestations of the disease. Only a few cases of primary cutaneous plasmacytoma have been published in the Korean dermatologic literature. Herein, we report on an interesting case of primary cutaneous plasmacytoma with monoclonality of kappa chains.

Detection of Clonal T Cell Receptor ? Gene Rearrangement in Children with Acute Lymphoblastic Leukemia and Its Clinical Significance / 实用儿科临床杂志

Objective To investigate the clonal rearrangement of T cell receptor (TCR) ? gene which was of monoclonality,oligoclona-lity or clonal evolution /subclonality during the course of disease in patients with acute lymphoblastic leukemia (ALL) and its significance.Methods Between Sep. 2004 and Sep. 2007,70 patients with ALL were diagnosed in Department of Pediatrics of the First Affiliated Hospital of Guangxi Medical University,among which 51 cases were boys and 19 cases were girls.Their ages ranged from 2 years to 14 years (average age was 8.5 years).DNA samples were extracted from bone marrow cells or venous blood cells by phenol/phenol-isoamyl alcohol-chloroform/isoamyl alcohol law.DNA was amplified by polymerase chain reaction (PCR).Single strand conformation polymorphism analysis (SSCP) of silver stained technique was employed to detect PCR products.Results The amplification products of 23 cases of the 70 ALL patients were positive,in which 10 cases still had positive results in period of complete remission and had poor sensitivity to chemotherapeutic drugs,4 cases were of oligoclonality/ subclonality,and 2 cases were of clonal evolution with poor prognosis.Conclusions Detecting TCR ? gene rearrangement reflects clonal evolution of leukemia cells.The oligoclonality clonal evolution continues to exist,whose multiplication is the main reason of recurrent ALL.Detecting TCR? gene rearrangement,evaluating ALL of the patient's prognosis,the judgment of recurrence and the development of individualized treatment programs have great guiding significance,which can maximize the possibility of the sick children to make long-term disease-free survival and reduce the side effects of chemotherapy on the long-term basis.

A Case of Primary Cutaneous Plasmacytoma / 대한피부과학회지

Primary cutaneous plasmacytoma is a rare cutaneous B cell lymphoma characterized by monoclonal proliferation of mature plasma cells in the skin without systemic involvement. Although a significant proportion of patients, especially with multiple lesions, went on to develop systemic disease with a poor prognosis, the abnormal clone of plasma cells may arise in the skin and never progress to multiple myeloma involving the bone marrow in a number of patients. We report a case of primary cutaneous plasmacytoma and review data published in the literature. A 19-year-old man developed multiple 0.2 to 0.5cm sized erythematous grouped papules on his posterior neck for 4 years. Histopathologic examination represented superficial and deep interstitial and nodular dense infiltration of plasma cells showing monoclonal expression of immunoglobulin lambda light chain. F-18 FDG coincidence PET(CoDe-PET) scan and serum electrophoresis were within normal limit. Any systemic disease has not developed for 6 months after diagnosis.

Significance of Epstein-Barr Virus Detection in non-Hodgkin's Lymphoma in Korea / 대한암학회지

PURPOSE: To investigate whether non-Hodgkin's lymphoma of Korea is pathogenetically associated with Epstein-Barr virus (EBV). MATERIALS AND METHODS: We analyzed fifty nine paraffin-embedded tissue and 22 fresh frozen tissue samples from non-Hodgkin's lymphoma patients for the presence of EBV sequences by polymerase chain reactions (PCR), in situ hybridization (ISH) and assessed the clonality of EBV infected cells by Southern blot hybridization. RESULT: On ISH using oligonucleotide probes corresponding to EBV-encoded small RNAs (EBERs), 17 (28.8%) of 59 paraffin-embedded tissue samples showed positive hybridization signals localized over the nuclei of the tumor cells, but PCR using primers from Internal Repeat I or EBV-determined nuclear antigen 1 gene showed positive results in only 6 (10.2%) and 5 (8.5%) samples, respectively. ISH and PCR did not detect EBV sequences in 15 paraffin-embedded tissue samples of tuberculous lymphadenitis patients. In 22 fresh frozen tissue samples, PCR detected EBV sequences in three samples from peripheral T cell lymphoma (PTCL). In two of those three samples, Southern blot analysis showed that these viral DNAs were monoclonal and of latent form. CONCLUSION: Approximately 28.8% of non-Hodgkin's lymphoma were related to EBV in Korea. Monoclonality of those EBV DNAs implies that virus infection preceded malignant transformation, suggesting that EBV may play a role in lymphomagenesis.

Cutaneous Plasmacytoma Associated with Multiple Myeloma / 대한피부과학회지

A 52-year-old man with multiple myeloma developed cutaneous nodules while being treated with melphalan and prednisolone. A biopsy specimen showed dermal infiltration by well differentiated plasma cells similar to those found on bone marrow biopsy. The use of peroxidase anti-peroxidase to demonstrate the monoclonality or polyclonality of the cytomplasmic immunoglohulins in the tumor cells revealed a positivity for IgG and 1 chain (ie, monotypic staining). Ultrastructurally, each plasmacytoma cell contained varyting amounts of rough endoplasmic reticulum and Golgi-apparatus. The cutnneous nodules completely disappeared after radiotherapy