[Protein array technology applied in high throughput monoclonal antibody generation].

UNLABELLED: To reduce the huge labor-cost in the screening in traditional monoclonal antibody generation, We established a new system for monoclonal antibody generation integrating with protein array. BALB/c mice were immunized by eight recombinant proteins respectively, and the positive hybridoma cells were obtained by cell fusion and ELISA screening. All the eight kinds of positive hybridoma cells were mixed, cloned, screened by protein array, and definite dilution cloned. RESULTS: 175 single cell clones were obtained by complex cloning, and 119 of those were positive clones. Then 8 positive cell lines were generated by the following 2 rounds definite dilution cloning. By comparing with the traditional method, we got 8 monoclonal antibodies using the combined protein array screening and multiplex cloning method in 1 cycle, and fewer amounts of antigens were used. As a result, the combined protein array and multiplex cloning method could be used as an economical, rapid and simple tool applying in high throughput monoclonal antibody generation.

Mitosin/CENP-F is a conserved kinetochore protein subjected to cytoplasmic dynein-mediated poleward transport.

Mitosin/CENP-F is a human nuclear protein transiently associated with the outer kinetochore plate in M phase and is involved in M phase progression. LEK1 and CMF1, which are its murine and chicken orthologs, however, are implicated in muscle differentiation and reportedly not distributed at kinetochores. We therefore conducted several assays to clarify this issue. The typical centromere staining patterns were observed in mitotic cells from both human primary culture and murine, canine, and mink cell lines. A C-terminal portion of LEK1 also conferred centromere localization. Our analysis further suggests conserved kinetochore localization of mammalian mitosin orthologs. Moreover, mitosin was associated preferentially with kinetochores of unaligned chromosomes. It was also constantly transported from kinetochores to spindle poles by cytoplasmic dynein. These properties resemble those of other kinetochore proteins important for the spindle checkpoint, thus implying a role of mitosin in this checkpoint. Therefore, mitosin family may serve as multifunctional proteins involved in both mitosis and differentiation.

Effects of lipopolysaccharides on calcium homeostasis in isolated pancreatic acinar cells of rat.

AIM: To investigate the effects of lipopolysaccharides (LPS, endotoxin) on the calcium content in pancreatic acinar cells and the origin of Ca2+ during calcium overload induced by LPS, further to explore the mechanism of LPS in inducing calcium overload and pancreatic acinar cell injury. METHODS: Male rat pancreatic acinar cells were isolated by collagenase digestion and loaded with Fluo-3/AM, then exposed to varying doses of LPS (from 1 mg/L to 20 mg/L). The dynamic change of [Ca2+]i in single pancreatic acinar cell in the absence and presence of Ca2+ in extracellular fluid was determined by laser scanning confocal microscopy. Cell viability was determined by MTT at different time points after treatment with LPS. RESULTS: Under physiological calcium concentration in extracellular fluid, LPS (10 mg/L) initiated a rapid, concentration-dependent rise in intracellular [Ca2+]i and consequent cell damage (P<0.05). LPS induced a slight rise of [Ca2+]i in the calcium-free extracellular fluid containing egtazic acid 1 mmol/L and addition of extracellular calcium in the presence of LPS resulted in a more immediate and remarkable rise of [Ca2+]i, which reached the peak value within 150 s and maintained the value sustainedly. Egtazic acid attenuated LPS-induced cell damage (P<0.05). The increase in intracellular [Ca2+]i preceded the pathological alteration of pancreatic acinar cells. CONCLUSION: LPS directly induced the injury and the disorder of calcium homeostasis in isolated rat pancreatic acinar cell. Calcium overload is an early event in the pathogenesis of LPS-induced cell damage. Origin of the [Ca2+]i in cytoplasma of pancreatic acinar cells during calcium overload is mainly due to the influx of extracellular Ca2+. Calcium homeostasis disorder may be one of the causes or at least an important mediator of LPS-induced pancreatic acinar cell damage.

Application of Free-flow Electrophoresis to the Separation of Murine Lymphocytes.

Free-flow electrophoresis offers not only the all-in-solution separation process but also very gentle separation conditions, and it can be used for continuous separation and preparation, so it has been widely applied in the fields of biochemistry and cell biology. Using this technique to separate insoluble particles such as cells, both high separation efficiency and high activity and viability could be obtained. Murine lymphocytes were separated in low ionic strength triethanolamine buffer by free-flow electrophoresis, the cell fractions were detected and characterized by means of UV spectrometry, immune fluorescence labeling and flow cytometry. Results indicated that T and B lymphocytes were well separated with high viability.