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T E Jessen

Publications and source records attributed to T E Jessen.

10 recordsLinked to original sources
PubMed2004

TSG-6 and calcium ions are essential for the coupling of inter-alpha-trypsin inhibitor to hyaluronan in human synovial fluid.

OBJECTIVE: To investigate the role of tumor necrosis factor stimulated gene 6 (TSG-6) and metal ions in the coupling of inter-alpha-trypsin inhibitor (ITI) to hyaluronan in human synovial fluid. DESIGN: The concentration of ITI heavy chains bound to hyaluronan was determined by a two-step electrophoretic technique. Synovial fluid, TSG-6 depleted synovial fluid and metal chelated synovial fluid were tested for their ability to support the coupling of ITI heavy chains to hyaluronan. RESULTS: When synovial fluid was mixed with an ITI-source (serum or purified ITI), coupling of ITI heavy chains to hyaluronan took place. TSG-6 immunodepleated synovial fluid lost the coupling activity, but addition of recombinant TSG-6 restored the activity. EDTA inhibited the coupling activity, but combinations of the metal-ion chelators Mg-EGTA and Ca-EGTA demonstrated, that Ca++ is essential for the coupling of ITI heavy chains to hyaluronan. CONCLUSIONS: Tumor necrosis factor stimulated gene 6 (TSG-6) and calcium ions are both essential for the coupling of inter-alpha-trypsin inhibitor to hyaluronan in human synovial fluid.

Alpha-Globulins↗
PubMed2003

Role of tumour necrosis factor stimulated gene 6 (TSG-6) in the coupling of inter-alpha-trypsin inhibitor to hyaluronan in human follicular fluid.

Binding of the plasma proteinase inhibitor inter-alpha-trypsin inhibitor (ITI) to hyaluronan is necessary for normal expansion of the cumulus-oocyte complex. Lack of ITI causes severe infertility. Binding of ITI to hyaluronan depends on calcium ions and coupling activity present in follicular fluid (Ødum et al., 2002). The complexes formed by this process contain ITI heavy chains bound to hyaluronan, and bikunin is detached from ITI during the coupling reaction. In the present study, an electrophoretic technique by which hyaluronan-bound ITI is immobilized was used to demonstrate that tumour necrosis factor stimulated gene 6 (TSG-6) is necessary for the coupling reaction. Thus, immunoprecipitation of TSG-6 in human follicular fluid eliminates the coupling reaction and re-addition restores the activity. However, it appears that components other than hyaluronan, ITI, calcium ions and TSG-6 are involved in the coupling reaction, as in vitro incubation of these components does not generate stable complexes between ITI heavy chains and hyaluronan unless some follicular fluid is added. In conclusion, TSG-6 is necessary for the coupling of ITI to hyaluronan, but at least one additional component in follicular fluid is essential.

Alpha-Globulins↗
PubMed2002

Characterization of the coupling activity for the binding of inter-alpha-trypsin inhibitor to hyaluronan in human and bovine follicular fluid.

The plasma proteinase inter-alpha-trypsin inhibitor is necessary for normal expansion of the cumulus-oocyte complex (COC) and lack of inter-alpha-trypsin inhibitor results in severe infertility. After diffusion from the circulation into the follicles, inter-alpha-trypsin inhibitor is incorporated into the extracellular hyaluronan network of the expanding COC. However, mixing isolated inter-alpha-trypsin inhibitor with hyaluronan in vitro does not result in coupling to hyaluronan. Other components must be present. A recently developed electrophoretic technique by which hyaluronan-bound inter-alpha-trypsin inhibitor is immobilized was used to demonstrate coupling activity in human and bovine follicular fluid that is necessary for the formation of a firm binding between inter-alpha-trypsin inhibitor heavy chains and hyaluronan, as observed in vivo. No coupling activity could be detected in human serum. Coupling occurred only in the presence of follicular fluid. The coupling activity of follicular fluid was irreversibly destroyed by heat treatment, lowering of pH or tryptic digestion, indicating that the coupling activity is associated with a protein. Calcium ions are essential for the coupling reaction. The binding reaction in vitro using intact inter-alpha-trypsin inhibitor is slow and occurs over 24 h. The early-formed complexes between inter-alpha-trypsin inhibitor and hyaluronan contain small amounts of bikunin, whereas the end product contains heavy chains and essentially no bikunin. The heavy chains released from inter-alpha-trypsin inhibitor by NaOH treatment bound immediately to hyaluronan, indicating that the dissociation of heavy chains from inter-alpha-trypsin inhibitor is the rate-limiting step. In conclusion, at least four components are essential for the covalent binding of heavy chains to hyaluronan: inter-alpha-trypsin inhibitor and calcium from plasma, hyaluronan and one or more proteins found in follicular fluid.

Alpha-Globulins↗
PubMed2001

Glycosaminoglycan-bound and free inter-alpha-trypsin inhibitor components of follicular fluid.

The proteinase inhibitor inter-alpha trypsin inhibitor (ITI) is a blood-derived protein necessary for normal female fertility. Absence of ITI leads to ovulation of naked oocytes that cannot fertilise. ITI consists of two heavy chains (ITI-HC) and bikunin linked by a chrondroitin sulphate. By binding to hyaluronate, ITI-HC stabilises the extracellular matrix, but ITI-HC also binds to proteoglycans in follicular fluid. In vivo concentrations of ITI components in preovulatory follicular fluid, free as well as bound to hyaluronate or proteoglycan, are unknown. In order to quantify these components, 58 follicular fluids and 13 blood samples were collected in connection with in vitro fertilisation and embryo transfer treatment of 13 women. Quantitation of glycosaminoglycan-bound ITI-HC was performed after separation from free ITI in agarose gel. ITI components were determined by immunoelectrophoresis and hyaluronate by an ELISA method. The follicular fluid concentration of ITI was on average 70% of that in plasma and the concentration of hyaluronate remained low despite follicular production, suggesting that the production of hyaluronate is the rate-limiting step in the formation of the extracellular matrix of the oocyte-cumulus complex. In follicular fluid, the concentration of free ITI-HC was higher than that of glycosaminoglycan-bound ITI-HC. Addition of exogeneous hyaluronate doubled the amount of hyaluronate-bound ITI-HC, further supporting the notion that ITI in follicular fluid is not rate-limiting for cumulus expansion in vivo.

Adult↗
PubMed1996

False negative anti-HIV-1/HIV-2 ELISAs in acute HIV-2 infection.

Since HIV-2 was isolated in 1986, only 1 case of acute HIV-2 infection has been reported. We have identified another patient with primary HIV-2 infection. Follow-up samples were requested from the patient due to discrepant results. The HIV-2 infection was confirmed with HIV-2-specific proviral DNA amplification by PCR. The HIV-2 seroconversion panel obtained was used to evaluate the sensitivity of both combined and specific ELISAs currently in use in Europe, and to investigate the Western-blot patterns on both HIV-1-and HIV-2-specific Western blots. The window period was determined to be less than 37 days with the most sensitive assays. A remarkable difference in sensitivity to HIV-2 antibodies in acute HIV-2 infection was found in combined HIV-1/HIV-2 ELISAs. Three out of the 4 combined sandwich ELISAs appeared to be less sensitive than the indirect ELISAs in HIV-2 seroconversion, leading to a prolonged window period. One HIV-2-specific ELISA was also negative on the first sample, but positive on the second sample. In the HIV-2 Western blot, early reaction with HIV-2-specific env and gag proteins was seen, whereas the HIV-1 Western blot on the first sample revealed gag (p24, p55) reactivity only.

AIDS Serodiagnosis↗
PubMed1994

In vivo binding of human inter-alpha-trypsin inhibitor free heavy chains to hyaluronic acid.

In vivo binding of human inter-alpha-trypsin inhibitor to hyaluronate was investigated by immunoelectrophoretic techniques. Pathological synovial fluids and follicular fluids both contain high concentrations of soluble hyaluronate. Heavy chain epitopes of inter-alpha-trypsin inhibitor were firmly associated with the hyaluronate in synovial fluid and follicular fluid. The hyaluronate-bound inter-alpha-trypsin inhibitor epitopes did not cross-react immunologically with bikunin. Several hyaluronate-bound inter-alpha-trypsin inhibitor fragments with molecular masses in the range 120,000-30,000 Da were demonstrated by immunoblotting. Heavy chain 1 of inter-alpha-trypsin inhibitor was shown to associate with hyaluronate by amino acid sequence analysis of isolated hyaluronate-bound proteins. These data indicate that in vivo metabolism of inter-alpha-trypsin inhibitor takes place in pathological synovial fluid and in ovarian follicular fluid shortly before ovulation.

Alpha-Globulins↗
PubMed1988

Carbohydrate as covalent crosslink in human inter-alpha-trypsin inhibitor: a novel plasma protein structure.

The primary structure of inter-alpha-trypsin inhibitor is partially elucidated, but controversy about the construction of the polypeptide backbone still exists. We present evidence suggesting that inter-alpha-trypsin inhibitor represents a novel plasma protein structure with two separate polypeptide chains covalently crosslinked only by carbohydrate (chondroitin sulphate).

Alpha-Globulins↗
PubMed1985

Hemolytic plate assay for quantification of active human complement component C3 using methylamine-treated plasma as complement source.

A hemolytic plate assay specific for active human complement component C3 is described. The method is well suited for tracing active C3 during preparative purification or for screening of plasma samples. The assay is based on activation of the alternative pathway of complement by unmodified rabbit erythrocytes. Plasma treated with methylamine supplies the essential complement components other than C3. The lytic reaction is complete in 5 h at 37 degrees C and is unchanged by incubation overnight. The dose-response curve, i.e., lysis diameter versus logarithm of C3 concentration, is linear within 0.1-10 times normal plasma concentrations of C3. The standard deviation is below 10%. The hemolytic agarose plates are easy and inexpensive to prepare, and they can be stored at 4 degrees C for 2 weeks before use. This paper describes the optimal conditions of the assay and proves its specificity. Its use in C3 preparation and plasma screening for C3 is discussed.

Animals↗
PubMed1983

A simple alternative pathway for hemolytic assay of human complement component C3 using methylamine-treated plasma.

A quantitative, alternative pathway (AP) hemolytic assay for human complement component C3 has been developed. This AP-C3 assay is inexpensive, rapid, simple, reproducible and insensitive to C3 degradation products. The AP-C3 assay uses rabbit erythrocytes as complement activator and methylamine-treated plasma, depleted of C3 and C4, as complement source. Rabbit erythrocyte sensitivity varies little from batch to batch, and remains unaltered for at least one month in Alsever's solution. Methylamine plasma may be stored at -20 degrees C for 3 months. AP-C3 lysis of 5-25% of erythrocytes is complete in 20 min and does not change subsequently. The AP-C3 assay is optimally stable at 2 mM Mg2+, 5 mM EGTA and at 5 X 10(7) erythrocytes/ml, yet insensitive to at least 20% deviation in these concentrations. The AP-C3 assay is specific to functional C3 and well suited for determination in plasma samples and during C3 preparation. Adding excessive amounts of C3c or plasma components other than C3 does not change the hemolytic response. The level of native C3 in plasma from 14 donors relative to a reference plasma pool ranged from 0.78 to 1.23. The standard deviation of relative C3 determinations did not exceed 2%.

Animals↗