Dataset Information

Immunomodulation by alpha(1)-proteinase inhibitor: lack of chemotactic effects of recombinant human alpha(1)-proteinase inhibitor from yeast on human peripheral blood granulocytes.

ABSTRACT: INTRODUCTION: Recombinant alpha(1)-proteinase inhibitor, clinically developed for inhalative augmentation therapy in patients with alpha(1)-proteinase inhibitor deficiency or cystic fibrosis, may directly contribute to leukocyte accumulation as it may function as a chemoattractant. The migratory effects of yeast-derived human recombinant alpha(1)-proteinase inhibitor on human peripheral blood neutrophils and eosinophils were therefore tested in vitro. MATERIALS AND METHODS: Human peripheral blood leukocytes were prepared from forearm venous blood and tested for migration toward various preparations of yeast-derived recombinant alpha(1)-proteinase inhibitor in modified Boyden-chamber micropore filter assays. RESULTS: No direct effects of yeast-derived recombinant human alpha(1)-proteinase inhibitor on in vitro migration of isolated neutrophils or eosinophils were seen. CONCLUSIONS: The lack of direct chemotactic effects of recombinant human alpha(1)-proteinase inhibitor despite anti-inflammatory effects in other biological activities of leukocytes may contribute to the preserved antibacterial defense mechanisms observed in patients under experimental augmentation therapy with inhaled alpha(1)-proteinase inhibitor.

SUBMITTER: Mosheimer B

PROVIDER: S-EPMC2766450 | biostudies-other | 2007 Nov-Dec

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:Human alpha 1-proteinase inhibitor (alpha 1-PI) yielded nine fragments on cleavage with CNBr. The amino acid sequences of these fragments were determined. Three of these CNBr-cleavage fragments, namely fragment I (residues 64-220), fragment II (residues 243-351) and fragment III (residues 1-63), were found to bind rabbit polyclonal antibodies against chemically oxidized alpha 1-PI and mouse polyclonal antibodies against native alpha 1-PI by the Bio-Dot method (enzyme-linked immunosorbent assay on nitrocellulose). These fragments, I, II and III, inhibited by 60%, 25% and 5% respectively the binding between alpha 1-PI and the rabbit antibodies. Fragments I, II and III were subjected to proteolytic digestion, and 15, ten and five peptides were obtained from these fragments respectively. Only four of these peptides showed binding to the mouse antibodies against native alpha 1-PI. These were residues 40-63, 79-86, 176-206 and 299-323. A panel of monoclonal antibodies was prepared by conventional hybridoma technology, with chemically oxidized alpha 1-PI as the antigen. The ability of the monoclonal antibodies to bind native alpha 1-PI and CNBr-cleavage fragments I-III was determined. The monoclonal antibodies fell into three categories. Most (over 90%) belonged to group I, which was capable of binding alpha 1-PI and only fragment I. Antibodies in groups II and III bound alpha 1-PI and either fragment II or fragment III respectively. The ability of the peptides derived from proteolytic digestion of fragments I, II and III to bind three monoclonal antibodies representing each of the three groups was determined. Among all the peptides tested, only one (residues 176-206) derived from fragment I showed binding to the antibodies from group I, one (residues 299-323) derived from fragment II showed binding to the antibodies from group II, and one (residues 40-63) from fragment III showed binding to the antibodies from group III. Each of these three peptides also inhibited the binding between alpha 1-PI and the corresponding monoclonal antibodies. From these data we concluded that at least four epitopic regions (residues 40-63, 79-86, 176-206 and 299-323) were present in alpha 1-PI. Specific monoclonal antibodies to three of these sites were obtained.

Project description:BackgroundHuman alpha1-proteinase inhibitor (alpha1-PI), also known as antitrypsin, is the most abundant serine protease inhibitor (serpin) in plasma. Its deficiency is associated with development of progressive, ultimately fatal emphysema. Currently in the United States, alpha1-PI is available for replacement therapy as an FDA licensed plasma-derived (pd) product. However, the plasma source itself is limited; moreover, even with efficient viral inactivation steps used in manufacture of plasma products, the risk of contamination from emerging viruses may still exist. Therefore, recombinant alpha1-PI (r-alpha1-PI) could provide an attractive alternative. Although r-alpha1-PI has been produced in several hosts, protein stability in vitro and rapid clearance from the circulation have been major issues, primarily due to absent or altered glycosylation.ResultsWe have explored the possibility of expressing the gene for human alpha1-PI in the filamentous fungus Aspergillus niger (A. niger), a system reported to be capable of providing more "mammalian-like" glycosylation patterns to secretable proteins than commonly used yeast hosts. Our expression strategy was based on fusion of alpha1-PI with a strongly expressed, secreted leader protein (glucoamylase G2), separated by dibasic processing site (N-V-I-S-K-R) that provides in vivo cleavage. SDS-PAGE, Western blot, ELISA, and alpha1-PI activity assays enabled us to select the transformant(s) secreting a biologically active glycosylated r-alpha1-PI with yields of up to 12 mg/L. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis further confirmed that molecular mass of the r-alpha1-PI was similar to that of the pd-alpha1-PI. In vitro stability of the r-alpha1-PI from A. niger was tested in comparison with pd-alpha1-PI reference and non-glycosylated human r-alpha1-PI from E. coli.ConclusionWe examined the suitability of the filamentous fungus A. niger for the expression of the human gene for alpha1-PI, a medium size glycoprotein of high therapeutic value. The heterologous expression of the human gene for alpha1-PI in A. niger was successfully achieved to produce the secreted mature human r-alpha1-PI in A. niger as a biologically active glycosylated protein with improved stability and with yields of up to 12 mg/L in shake-flask growth.

Dataset Information

Immunomodulation by alpha(1)-proteinase inhibitor: lack of chemotactic effects of recombinant human alpha(1)-proteinase inhibitor from yeast on human peripheral blood granulocytes.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets