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PubMed2001

Expression of C1 esterase inhibitor by the baculovirus expression vector system: preparation, purification, and characterization.

C1 esterase inhibitor (C1INH) is an important regulator of the classical complement pathway. Hereditary deficiency of C1INH causes angioedema of the skin, gut, and respiratory tissues that may be fatal. C1INH replacement therapy may be lifesaving for patients with this disorder. The objective of this study was to evaluate the use of the baculovirus expression vector system for mass producing biologically active human recombinant (rC1INH). A recombinant baculovirus was constructed coding the human native (nC1INH) sequence under control of the polyhedrin promoter. Spodoptera frugiperda Sf-9 insect cells were infected with this recombinant baculovirus in a medium-scale (10-L) bioreactor to produce rC1INH with a specific activity of 45 U/mg. Purification of rC1INH from the culture harvested at 60 h postinfection yielded 5.9 microg rC1INH/mL supernatant of a 75-kDa product with a specific activity of 31,000 U/mg purified rC1INH compared to 71,000 U/mg purified nC1INH from human serum using the same procedure. This rC1INH was about 25 kDa smaller than nC1INH, suggesting that Sf-9 cells express underglycosylated rC1INH. Glycan analysis showed that both N-glycan and O-glycan chains were present in rC1INH. The N-glycan chains, released using PNGaseF and fluorescently labeled, were analyzed using exoglycosidase treatment and capillary electrophoresis. Their high-mannose structure was consistent with the known failure of the insect cell glycosylation pathway to afford the fully elaborated biantennary structures found on human native nC1INH.

Animals↗
PubMed1977

Hereditary deficiency of the third component of complement in a child with fever, skin rash, and arthralgias: response to transfusion of whole blood.

A previously well 34-month-old male presenting with fever, skin rash, and arthralgias was found to lack C3 by immunochemical (undetectable) and hemolytic (1% normal) assays. No infectious agent could be demonstrated. Protein levels of Clq. C4, C5, properdin, and C3b-INA and hemolytic activities of complement components C1 to C9 except C3 were normal or elevated; total hemolytic complement activity was 13% of normal and was reconstituted by purified C3. Properdin factor B was 702 (normal 175 to 275) mug/ml, and was not cleaver upon addition of zymosan or cobra venom factor. The serum had normal immune adherence activity, but was deficient in ability to opsonize Candida albicans for uptake and Escherichia coli for killing by neurophils, generate neutrophil chemotactic factors and inhibit the growth of E. coli; these activities were restored by purified C3. A transfusion of 320 ml 1-hour-old normal whole blood on the fifty-second day resulted in transitory elevation of the C3 level to 25 mg/dl with a fall-off (approximately 2 1/2% per hour) to undetectable levels by 69 hours; it was followed by disappearance of the skin rash and arthralgias and return to normal of the previously elevated temperature and CRP levels. C3 levels in family members (seven of 24 half-normal), lack of anti-C3 activity, normal C3b-INA levels and a normal rate of catabolism of transfused C3 indicated that the deficiency was inherited with autosomal codominance and involved decreased synthesis of C3. Thus, this child is a unique individual with inherited C3 deficiency presenting with absence of repeated infections, whose symptoms of fever, skin rash, and arthralgia were abated by whole blood transfusion.

Blood Transfusion↗
PubMed2001

Microheterogeneous changes of the C1-esterase inhibitor in plasma cannot predict operability, postoperative complications, or recurrence in cancer surgery.

OBJECTIVE: To find out if microheterogeneous changes--such as in molecular weight, isoelectric point, electrophoretic mobility, lectin binding or complexation of the C1-esterase inhibitor--exist in plasma samples from various subgroups of patients. If so, whether these differences could be used diagnostically in single plasma samples from patients with cancer for prognostic assessment of operability or risk of recurrence, and whether any change indicated an increased risk for development of postoperative complications. DESIGN: Retrospective study. SETTING: University hospital, Sweden. SUBJECTS: 16 patients operated on as emergencies for acute peritonitis, 118 patients electively operated on for benign diseases, 274 patients electively operated on for cancer, and 212 patients admitted with acute abdominal pain. MAIN OUTCOME MEASURES: Curative operation, diagnoses, postoperative complications, recurrence of cancer within 2 years. RESULTS: There were no biochemical differences in the C1-esterase inhibitor between single or sequential plasma samples from four large groups of patients with benign disease, cancer, or inflammatory disease, with operable or inoperable cancer, with postoperative complications or not, or with or without early recurrence of cancer. CONCLUSIONS: Specialised biochemical analyses of C1-esterase inhibitor, the most important plasma protease inhibitor of the complement and kinin systems and of contact activation in plasma, cannot be used for prognostic assessment of operability, risk of postoperative complications, or risk of recurrence in patients with cancer.

Abdomen, Acute↗
PubMed2006

Classical pathway complement activity in Familial Mediterranean fever.

OBJECTIVES: The present study emphasizes the important role of the immune reactions in the pathogenesis of Familial Mediterranean fever. In the present study, the total hemolytic activity of the complement and the activities of individual complement components, C1, C2, C3, and C4, were determined in the blood serum of 32 patients with FMF and 28 healthy subjects. DESIGN AND METHODS: Hemolytic assay was applied, measuring THAC and individual complement components' activities. The patients were divided into 3 groups upon the regularity of colchicine therapy: patients receiving regular, irregular and not receiving colchicine treatment for at least 1 year. RESULTS: No significant changes in the hemolytic activities of the C1, C2, C3, and C4 complement components were found between the healthy subjects and those FMF patients, who were receiving regular colchicine treatment. CONCLUSIONS: Our data obtained have raised a number of important questions relevant to FMF pathogenesis and once again confirms the efficiency of regular colchicine treatment.

Adult↗
PubMed2004

Oxandrolone treatment of childhood hereditary angioedema.

BACKGROUND: The virilizing effects of danazol, stanozolol, and methyltestosterone significantly restrict the usefulness of these agents in the treatment of children with hereditary angioedema (HAE). Oxandrolone is a synthetic anabolic steroid with limited virilizing effects that has been used in a variety of pediatric conditions and has an acceptable safety profile. OBJECTIVE: To report the effective use of oxandrolone in a 6-year-old boy with recurrent, life-threatening episodes of angioedema. METHODS: Oxandrolone was administered at a dose of 0.1 mg/kg per day. Symptoms and laboratory findings were evaluated by parental report and laboratory analysis of serum C1 esterase inhibitor and C4 levels, respectively. RESULTS: Oxandrolone therapy resulted in a marked reduction in clinical episodes and normalization of serum complement levels; cessation of oxandrolone therapy resulted in recurrence of symptoms and decreased complement levels. However, early signs of virilization were noted. CONCLUSIONS: Oxandrolone treatment was associated with significant clinical and laboratory evidence of a therapeutic effect in a prepuberal boy with HAE. It is imperative to treat HAE with the lowest dose of oxandrolone that controls life-threatening episodes of angioedema.

Anabolic Agents↗
PubMed1991

Characterization of C1 inhibitor binding to neutrophils.

In a previous study we have isolated neutrophil membrane proteins that non-covalently bind to native C1-INH (105,000 MW) and a non-functional, degraded C1-INH (88,000 MW; C1-INH-88). To further characterize the binding nature, we have designed a novel kinetic C1 titration assay which enables not only a quantification of the removal of fluid-phase C1-INH by neutrophils, but also a concomitant measure of residual C1-INH function. Native C1-INH, when adsorbed to EDTA-pretreated neutrophils, lost its function in the inhibition of fluid-phase C1. The non-functional C1-INH-88, which is probably devoid of a reactive centre, was found to block the binding of native C1-INH to neutrophils. Pretreatment of neutrophils with serine esterase inhibitors did not abrogate binding capacity of the cells for C1-INH, whereas the binding affinity for C1-INH was lost when the cells were pretreated with trypsin. An array of human peripheral blood leucocytes and several lymphoid cell lines has surface binding sites for C1-INH, but not on human erythrocytes and U937 cells. Binding was further confirmed using (i) C1-INH-microsphere beads to neutrophils, in which the binding was blocked when pretreating neutrophils with excess C1-INH or with trypsin, and (ii) radiolabelled C1-INH to neutrophils, which was competitively blocked by unlabelled non-functional C1-INH-88. Desialylation of C1-INH significantly reduced its binding affinity for neutrophils, indicating that the membrane receptor sites on neutrophils could be specific for the binding of sialic acid residues on C1-INH. Overall, our studies indicate that neutrophils or other leucocytes possess specific surface binding sites for the sialic acid-containing portion of C1-INH.

Binding, Competitive↗
PubMed1986

C1 esterase inhibitor deficiency in X-linked hypogammaglobulinaemia: an anomaly fostering anaphylactoid reactions following intramuscular gammaglobulin administration.

A patient with apparent X-linked agammaglobulinaemia was found to be inordinately susceptible to anaphylactoid reactions to intramuscular injections of gammaglobulin. The patient was found also to have low levels of C1 esterase inhibitor (C1 INH). The possibility that the C1 INH deficiency and in this patient, whether genetic or acquired, fostered the susceptibility to the production of anaphylactoid reactions after gammaglobulin injections urges further studies of the association of C1 INH deficiency and anaphylactoid reactions to gammaglobulin injections. The possibility that C1 INH levels like C1q levels may be low in hypogammaglobulinaemic patients as a consequence of increased catabolism of this regulator of the complement system when IgG levels are low is considered.

Adult↗
PubMed1999

C1-inhibitor attenuates hyperacute rejection and inhibits complement, leukocyte and platelet activation in an ex vivo pig-to-human perfusion model.

Xenotransplantation may be a future alternative due to increased shortage of organs. Classical complement activation is central in hyperacute rejection in pig-to-human combinations. We investigated the effects of C1-inhibitor (C1-INH), a regulator of the complement and contact systems, on hyperacute rejection. Pig kidneys were perfused with fresh human blood to which either C1-INH (n = 6) or human serum albumin (n = 6) was added. The survival of the C1-INH perfused kidneys (mean 327 min) was significantly longer (p < 0.00001) than the controls (79 min). C1-INH substantially inhibited complement activation (C1rs-C1-INH complexes, C4bc, C3bc and terminal complement complex) (p < 0.001 for all) compared with the marked complement activation in the controls. No contact activation was found. Leukocytes and platelets were substantially activated (counts, myeloperoxidase, beta-thromboglobulin, thrombospondin, soluble P-selectin) in the control group, and this activation was markedly reduced by C1-INH (p < 0.02 for all). Immunohistochemistry showed less C1q, C3, TCC, IgG and fibrin deposition in the C1-INH group. C1-INH may be useful to attenuate hyperacute rejection, probably through inhibition of complement. The reduced activation of neutrophils and platelets may mainly be secondary to inhibition of complement.

Animals↗