Copper staining method for extracting biologically active proteins from native gels.

An attempt was made to make protein bands visible on native gel using copper staining, since such a mild staining procedure would make the entire native gel electrophoresis process non-denaturing. Copper staining not only was able to detect various proteins on native gel with reasonable sensitivity, but also made extraction and recovery of active proteins possible from the gel using a gentle procedure.

Coexpression of G-CSF with an unglycosylated G-CSF receptor mutant results in secretion of a stable complex.

Previously, we have shown that the entire extracellular domain of the granulocyte-colony stimulating factor receptor (sG-CSFr) produced in Chinese hamster ovary (CHO) cells forms a stable complex with its ligand G-CSF, at a stoichiometry of 2:2. A truncated receptor molecule consisting of the cytokine receptor homology domain and N-terminus Ig-like domain (Ig CRH) behaves quite similarly. Both of these forms of the receptor are highly glycosylated. To address the importance of glycosylation toward receptor activity and stability, and possibly obtain nonglycosylated receptor for crystallization, mutations were made to replace four Asn residues which are N-glycosylated in the truncated receptor. Virtually no receptor was recovered from conditioned media of CHO cells transfected with this mutant construct, although a high-level of mRNA coding for receptor was detected; this mRNA was translated as determined by Western blots of cell lysates. These results indicate that the translated product is apparently not secreted from these cells. Cells transfected with mutant receptor cDNA were cotransfected with a cDNA construct expressing G-CSF in which the single O-glycosylation site was eliminated by mutation. Upon fermentation of the cotransfectants, we observed a large amount of receptor-ligand complex in the conditioned media. The purified unglycosylated complex appeared to be of the same binding stoichiometry and approximate binding affinity as that of complex formed by addition of purified ligand and unmutated receptor. These results show that while glycosylation of sG-CSFr is not necessary for ligand binding, it appears to be crucial in folding and export from the cell.

[Detection of human cytomegalovirus-antigen in peripheral blood cells by using flow-cytometer].

Prophlaxis of CMV-associated disease and/or early initiation of therapy is important in the management of patients with CMV infection. Recently, we developed the CMV antigenemia assay: a rapid and quantitative method based on the detection of CMC antigens in peripheral blood leukocytes by flow cytometry. Heparinized peripheral blood was obtained from healthy donors, bone marrow transplantation patients, patient with collagen disease and patients with adult T cell leukemia. To determine the phenotype of HCMV-infected mononuclear cells, the following phycoerythrin-conjugated mAb were used: CD8, CD15. These mAds were added to the whole blood and incubated. After the hemolysis, the cells were fixed with 4% paraformaldehyde and 0.3% NP-40. To determine the HCMV-infected cells, the following mAb were used in flow cytometry analysis: E13 (Chemicon Inc., Toyo) against HCMV IEA. As a secondary antibody, a FITC-conjugated goat anti-mouse IgG. In the bone marrow transplant patients, CMV-associated antigen was positive in their monocytes and polymorphocytes. In the patient with collagen disease, CMV-antigen was positive in their lymphocytes and monocytes. Our study demonstrates that the detection of CMV antigen-positive blood leukocytes by FACScan is a rapid and quantitative method and useful for the diagnosis and monitoring of CMV-associated CMV-associated disease. The CMV blood antigen assay by FACScan will facilitate the initiation of early treatment with ganciclovir of CMV-associated disease or the administration of prophylactic ganciclovir for preventing the disease.

[Effect of macrolides on cytokine mRNA expression in human whole blood model].

Recently, low dose and long term use of Macrolides (Mls) has been reported to be effective in treatment of chronic lower respiratory tract infections, however its mechanism is still obscure. We evaluated the effect of Mls (EM, AZM, RKM) on cytokine mRNA expressions. We preincubated the whole blood with several concentrations of Mls and removed the Mls and then stimulated human whole blood with LPS as an experimental vivo model. In order to examine cytokine mRNA expressions, we used the RT-PCR method. Cytokine mRNA expressions were suppressed significantly (p < 0.05) by pretreatment with EM, AZM; moreover, the suppression was peaked at low concentrations (0.04 approximately 0.2 microgram/ml). Although, Cytokine mRNA expressions were not suppressed by pretreatment with RKM. These results suggest that EM, AZM have suppression on Cytokine mRNA expressions, and consequently, this suppression has a reasonable effect for DPB patients.