Levels Of Chemotactic Activity Research Articles

Expression, high-pressure refolding and purification of human leukocyte cell-derived chemotaxin 2 (LECT2)

Human leukocyte cell-derived chemotaxin 2 (LECT2) is a chemotactic factor for neutrophils and a 16-kDa secreted protein consisting of 133 amino acids with three intramolecular disulfide bonds. Here, we propose an efficient method for the preparation of human LECT2 using a high hydrostatic pressure (HHP, 200MPa) refolding technique. When LECT2 was over-expressed in Escherichia coli cells, most of LECT2 molecules became insoluble inclusion bodies (IBs). HHP was applied to the refolding of LECT2 from insoluble IBs, which dramatically improved the yield of the active LECT2. CD and NMR measurements demonstrated that the refolded LECT2 had a tertiary structure indistinguishable from the solubly expressed LECT2. In addition, both the refolded and solubly expressed LECT2 showed the same level of chemotactic activity.

Detection of interleukin 8 biological activity in synovial fluids from patients with rheumatoid arthritis and production of interleukin 8 mRNA by isolated synovial cells

The presence of neutrophils in the synovial joint of patients with rheumatoid arthritis (RA) is thought to be due to the activity of chemotactic factors released by activated cells in the joint. We have shown in this report, for the first time, the abundance of one such factor, interleukin 8 (IL 8), in the synovial fluid of patients both with RA and other non-RA joint diseases, and the spontaneous production of IL 8 mRNA by RA synovial cells in culture. There was no correlation between the levels of chemotactic activity and IL 8 protein, suggesting that other factors with similar neutrophil chemotactic activity are also present in the synovial fluid exudate. In support of this concept neither the level of chemotactic activity nor IL 8 protein levels correlated with neutrophil or leukocyte infiltration, indicating that the mechanism of migration into the inflammatory environment of the joint is complex. Such migration is likely to be due to a number of chemotactic signals in addition to IL 8, which may either synergize with, or inhibit, the action of IL 8.

Spontaneous chemotaxis in acute glomerulonephritis: Demonstration of a positive correlation with disease activity

Normal human serum or plasma that has been immediately heat-inactivated upon collection contains very low levels ofchemotactic activity which we term “spontaneous chemotactic activity.” The source of this activity is unknown, but may, at least in part, reflect in vivo activation of the complement system. We have found abnormally increased spontaneous chemotactic activity in the plasma and sera of 19 children during the acute phase of poststreptococcal glomerulonephritis. Addition of immune complexes to unheated sera of the patients failed to generate additional chemotactic activity above that of the spontaneous levels. Also, neutrophis from these patients with increased spontaneous chemotactic activity responded poorly in vitro to chemotactic factors generated from normal control sera. All of these abnormalities disappeared with clinical resolution of the disease within 6 to 18 months following its acute phase. Healthy children with a prior history of poststreptococcal glomerulonephritis demonstrated normal chemotaxis; adults with chronic glomerulonephritis revealed similar but persistent abnormalities when studied sequentially over a period of 8 to 14 months. Thus, these abnormalities of chemotaxis appear to correlated with disease activity; they may have prognostic value.