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Biomedical subjects

M Kim

Publications and source records attributed to M Kim.

At least 91 records · Page 5Linked to original sources
PubMed2001

Clinical significance of intra-amniotic inflammation in patients with preterm labor and intact membranes.

OBJECTIVE: The purpose of this study was to determine the frequency and clinical significance of intraamniotic inflammation in patients with preterm labor and intact membranes. STUDY DESIGN: Amniocentesis was performed in 206 patients with preterm labor and intact membranes. Amniotic fluid was cultured for aerobic and anaerobic bacteria and mycoplasmas. The diagnosis of intraamniotic inflammation was made in patients with a negative amniotic fluid culture on the basis of amniotic fluid concentrations of interleukin-6 (>2.6 ng/mL, derived from receiver operating characteristic curve analysis). Statistical analysis was conducted with contingency tables and survival techniques. RESULTS: Intra-amniotic inflammation (negative amniotic fluid culture but elevated amniotic fluid interleukin-6) was more common than intra-amniotic infection (positive amniotic fluid culture regardless of amniotic fluid interleukin-6 concentration; 21% [44/206 women] vs 10% [21/206 women]; P <.001). The amniocentesisto-delivery interval was significantly shorter in patients with intra-amniotic inflammation than in patients with a negative culture and without an inflammation (median, 20 hours [range, 0.1-2328 hours] vs median, 701 hours [range, 0.1-3252 hours], respectively; P <.0001). Spontaneous preterm delivery of <37 weeks was more frequent in patients with intra-amniotic inflammation than in those with a negative culture and without inflammation (98% vs 35%; P <.001). Patients with intra-amniotic inflammation had a significantly higher rate of adverse outcome than patients with a negative culture and without intra-amniotic inflammation. Adverse outcomes included clinical and histologic chorioamnionitis, funisitis, early preterm birth, and significant neonatal morbidity. There were no significant differences in the rate of adverse outcomes between patients with a negative culture but with intra-amniotic inflammation and patients with intra-amniotic infection (positive culture regardless of amniotic fluid interleukin-6 concentration). CONCLUSION: Intra-amniotic inflammation/infection complicates one third of the patients with preterm labor (32%; 65/206 women), and its presence is a risk factor for adverse outcome. The outcome of patients with microbiologically proven intra-amniotic infection is similar to that of patients with intra-amniotic inflammation and a negative amniotic fluid culture. We propose that the treatment of patients in preterm labor be based on the operational diagnosis of intra-amniotic inflammation rather than the diagnosis of intra-amniotic infection because the latter diagnosis cannot be undertaken rapidly.

Amniocentesis↗
PubMed2001

Immunological alterations associated with Plasmodium vivax malaria in South Korea.

Various haematological and immunological studies on patients infected with Plasmodium vivax were undertaken, at diagnosis (day 0), after treatment with chloroquine but during primaquine treatment (day 10) and after all treatment (day 59), in South Korea (where there has been a recent and abrupt increase in the incidence of such infection). The main aims were to gain an understanding of the haemto-immunological alterations of this malarial infection, both before and after treatment, and to identify at least one useful marker for the diagnosis and post-treatment monitoring of P. vivax malaria. Thirty-eight patients with P. vivax malaria were compared with 20, apparently healthy controls. At diagnosis, the patients had lymphopenia, marked eosinopenia (the eosinophil count being correlated with the platelet count) and thrombopenia. Cells of most of the lymphocyte subsets investigated [i.e. CD3+, CD8+, CD19+, CD56+, CD3-/CD56+ and CD8+/CD56+ but not CD4+, CD3+/CD56+ or CD25+] were significantly less common among the lymphocytes of patients at diagnosis than among those of the controls. After initiating treatment, the numbers of CD19+ lymphocytes gradually increased (to normal values by day 59), whereas those of CD3+/56+ lymphocytes remained abnormally low throughout the follow-up period. The proportions of lymphocytes identified as CD4+ appeared to be unaffected by treatment. Although serum concentrations of IgE (and, to a lesser extent, IgM) were elevated in the patients at diagnosis, they were subnormal on day 10 post-treatment and normal at the day-59 follow-up. Serum concentrations of IgG and IgA in the patients were always found to be similar to those in the controls. At diagnosis the serum concentrations of complements C3 and C4 were significantly elevated in the patients. C3 remained at the same high concentration during follow-up but the concentration of C4, like that of IgE, was found to be subnormal on day 10 and normal 7 weeks later. The level of parasitaemia (%) was only found to be significantly correlated with haemoglobin concentration. The observation of eosinopenia with elevated IgE and C4 could be a useful indicator of P. vivax malaria, and treatment response could be followed by serial monitoring of serum concentrations of IgE and C4.

Adolescent↗
PubMed2001

Effects of adrenergic agonists on glycogenolysis in primary cultures of glycogen body cells and telencephalon astrocytes of the chick.

The glycogen body (GB) is at the dorsal area of the lumbosacral spinal cord in birds and is composed of uniform cells that are characterized by high-glycogen storage. Previous morphological and embryological examinations suggest that the GB is derived from the neuroepithelium and contains many blood vessels and a few nerve fibers. However, the function of the GB and role of the glycogen are unknown. Mammalian astrocytes are major sites for glycogen stores in the central nervous system. The metabolic features of astrocytes have been defined by using cultured cells. As a first step toward investigating the function of GB, we established primary culture of chicken GB cells and telencephalon astrocytes. The cultured GB cells maintained high glycogen content and glial fibrillary acidic protein (GFAP) in the cytoplasm. The glycogen content of GB cells significantly increased with the glucose concentration in the medium. The effects of adrenergic agonists on glycogenolysis were different between GB cells and telencephalon astrocytes. The telencephalon astrocytes shared similar characteristics of glycogenolysis with mouse astrocytes, which are mainly affected by beta adrenergic receptor. Although GB cells were affected by noradrenalin (both alpha and beta adrenergic agonist), they were not affected by beta adrenergic agonist. These results showed that cultured GB cells were considered as one lineage of astrocytes because of their reactivity to antibody against GFAP; however, the metabolic features of GB cells were different from those of telencephalon astrocytes.

Adrenergic Agonists↗
PubMed2001

Bovine follicular fluid and serum share a unique isoform of matrix metalloproteinase-2 that is degraded by the oviductal fluid.

Whereas the mammalian fertilization environment consists of possible products of the mutual interaction between oviductal and follicular fluids in addition to both fluid components, little is known regarding the interaction. In the present study, we have demonstrated that a mutual interaction occurs, resulting in the biochemical changes of follicular fluid components. Gelatin zymographic analyses of bovine follicular fluid (bFF) showed consistently a distinct, gelatinolytic activity having a molecular weight of 110 kDa (GA110) in addition to other gelatinases, whereas bovine oviductal fluid (bOF) showed a lack of GA110. Surprisingly, when bFF was mixed with bOF before zymography, the GA110 of bFF mostly disappeared at a 1:1 (v/v) mixture, completely disappeared at a 1:10 mixture, as fast as within 30 min after mixing. Other bFF gelatinase activities were not affected by bOF at 1:1 or 10:1 mixtures. Addition of EDTA or phenanthroline, but not of phenylmethylsulfonyl fluoride or trypsin inhibitor, to the mixture greatly increased the gelatinolytic activity of bFF GA110. The increased activity of bFF GA110 by EDTA was again abolished by subsequent bOF treatment. Addition of aminophenylmercuric acetate to the EDTA-treated bFF also abolished GA110; however, this was accompanied by the disappearance of other gelatinases, except the 62-kDa gelatinase, the activity of which increased as the treatment continued up to 24 h. Addition of EDTA or phenanthroline to the gelatin gel incubation buffer after electrophoresis abolished almost all gelatinases of bFF, except those of 88-84 kDa, demonstrating that they were indeed gelatinases or isoforms. Bovine serum and fetal bovine serum also showed the presence of GA110, the activity of which was increased by EDTA. However, ovarian granulosa cell homogenate did not exhibit GA110. Immunoblot experiments using antibodies against matrix metalloproteinase (MMP)-2 and MMP-9 demonstrated that bFF GA110 was an isoform of MMP-2, and that the 62-kDa form was an active form of MMP-2. Disappearance of immunoreactive GA110 of bFF and serum by bOF was also observed. Based on these observations, we conclude that bFF and bovine serum share a unique isoform of MMP-2, and that bOF can specifically degrade the isoform, suggesting that a mutual interaction between bFF and bOF could occur at the time of ovulation.

Animals↗
PubMed2001

Effect on the healing of periapical perforations in dogs of the addition of growth factors to calcium hydroxide.

The purpose of this study was to investigate the effect of the addition of platelet-derived growth factor-BB and insulin-like growth factor-I to calcium hydroxide in the repair of apical perforations in dogs. Fifty-one premolar teeth of four beagle dogs were used. After developing periapical lesions root apices were artificially perforated. The teeth were divided into the three groups: group 1, the apical perforations were not sealed; group 2, the perforated areas were obturated with calcium hydroxide; and group 3, calcium hydroxide plus growth factors was applied to the sites of perforation. All canals were filled by a lateral condensation technique. Animals were killed 12 wk later, and sections were hematoxylin & eosin-stained and immunostained for osteonectin. The amount of inflammation was evaluated histomorphologically. The one-way ANOVA test demonstrated that the three groups were significantly different from one another. In group 3 there was no inflammatory reaction of apical tissue, and the connective tissue adjacent to the newly formed hard tissue was strongly immunostained for osteonectin. Most sections in group 1 showed no apical healing. Moderate healing was found in group 2. In conclusion the combination of platelet-derived growth factor-BB and insulin-like growth factor-I with calcium hydroxide improved healing of apical perforation in dogs.

Alveolar Bone Loss↗
PubMed2001

Cryptochrome 1, cryptochrome 2, and phytochrome a co-activate the chloroplast psbD blue light-responsive promoter.

The reaction center core of photosystem II is composed of two chlorophyll binding proteins, D1 and D2, that are encoded by the chloroplast genes psbA and psbD. These chlorophyll binding proteins are damaged during photochemistry, especially under high irradiance. Photosystem II function is maintained under these conditions through turnover and resynthesis of D1 and D2. Blue light-activated transcription of psbD from a special light-responsive promoter is part of the repair system. In this study, light-activated chloroplast and psbD transcription were studied after dark adaptation of 21-day-old light-grown Arabidopsis plants. Illumination of dark-adapted plants with red light increased chloroplast transcription activity and transcription from the psbD light-responsive promoter. Blue light further increased chloroplast transcription activity and stimulated differential transcription from the psbD light-responsive promoter. Photoreceptor mutants showed that blue light-specific activation of chloroplast transcription and the psbD light-responsive promoter involve cryptochrome 1 (cry1) or cryptochrome 2 (cry2) and phytochrome A (phyA). Blue light-induced activation of the psbD light-responsive promoter was normal in det2-1 and hy5-1 but attenuated in det3-1. Therefore, cry1/cry2/phyA-mediated blue light activation of the psbD light-responsive promoter in 21-day-old Arabidopsis plants does not involve hy5, a transcription factor that mediates other phyA and blue light-induced responses.

Arabidopsis↗
PubMed2001

Magnetic resonance reflects the pathological evolution of Wernicke encephalopathy.

BACKGROUND AND PURPOSE: Wernicke encephalopathy (WE) is an acute phase of Wernicke-Korsakoff syndrome. Pathologic findings change between acute and chronic phases. Only a few magnetic resonance imaging (MRI) studies have been done to date. METHODS: To correlate the MRI findings in acute and chronic stages of WE with the known pathologic information, 15 consecutive patients with WE were examined with MRI: 3 before thiamine treatment, 7 within 24 hours of thiamine treatment, 4 between the second and sixth day after thiamine treatment, and 1 fifty-five days after thiamine treatment. Nine of the patients had follow-up MRI between 2 days and 33 months. T1-weighted, proton, and T2-weighted axial images were obtained with additional 5-mm-thick T1-weighted sagittal and coronal images to better visualize the mammillary bodies. RESULTS: In the acute WE, MRI showed high signal intensityon T2-weighted images in periaqueduct and medial thalamic regions. In a few patients with alcoholism, vermian and mammillary body atrophies and third ventricular enlargements were noted. In the chronic phase of WE, T2 hyperintensity disappeared but mammillary bodies and cerebellar vermis became atrophic and third ventricular enlargements were evident. High signal intensity on T2-weighted images disappeared as early as 2 days, and atrophic changes appeared as early as 1 week. CONCLUSION: MRI is useful for in vivo monitoring and reflects the pathological evolution in acute and chronic phases of WE.

Acute Disease↗
PubMed2001

Genetic and biochemical characterization of a novel umuD mutation: insights into a mechanism for UmuD self-cleavage.

Most translesion DNA synthesis (TLS) in Escherichia coli is dependent upon the products of the umuDC genes, which encode a DNA polymerase, DNA polymerase V, with the unique ability to replicate over a variety of DNA lesions, including cyclobutane dimers and abasic sites. The UmuD protein is activated for its role in TLS by a RecA-single-stranded DNA (ssDNA)-facilitated self-cleavage event that serves to remove its amino-terminal 24 residues to yield UmuD'. We have used site-directed mutagenesis to construct derivatives of UmuD and UmuD' with glycines in place of leucine-101 and arginine-102. These residues are extremely well conserved among the UmuD-like proteins involved in mutagenesis but are poorly conserved among the structurally related LexA-like transcriptional repressor proteins. Based on both the crystal and solution structures of the UmuD' homodimer, these residues are part of a solvent-exposed loop. Our genetic and biochemical characterizations of these mutant UmuD and UmuD' proteins indicate that while leucine-101 and arginine-102 are critical for the RecA-ssDNA-facilitated self-cleavage of UmuD, they serve only a minimal role in enabling TLS. These results, and others, suggest that the interaction of RecA-ssDNA with leucine-101 and arginine-102, together with numerous other contacts between UmuD(2) and the RecA-ssDNA nucleoprotein filaments, serves to realign lysine-97 relative to serine-60, thereby activating UmuD(2) for self-cleavage.

Alleles↗
PubMed2001

Correlation between peritoneal mesothelial cell cytology and peritoneal histopathology with respect to prognosis in patients on continuous ambulatory peritoneal dialysis.

BACKGROUND: Sclerosing encapsulating peritonitis (SEP) is a serious complication seen in patients on long-term continuous ambulatory peritoneal dialysis (CAPD). We have previously reported that mesothelial cells in effluent dialysate significantly increased in size as the duration of CAPD progressed. In this study, we investigated the relationship between mesothelial cytology, histopathology of the peritoneum, and clinical outcomes of 34 CAPD patients. METHODS: When peritoneal dialysis catheters were inserted (n = 7) or removed (n = 27), a peritoneal biopsy was performed and results compared with mesothelial cytology in effluent dialysate. RESULTS: A significant positive correlation was noted between the duration of CAPD and the surface area of peritoneal mesothelial cells (r = 0.721, p < 0.0001). The surface area of mesothelial cells in peritoneal sclerosis (n = 9; 584 +/- 97 microm(2)) was significantly greater than in peritoneal fibrosis (n = 14; 389 +/- 26 microm(2), p < 0.05), pathologic acute peritonitis (n = 3; 223 +/- 10 microm(2), p < 0.005), and normal peritoneum (n = 7; 247 +/- 12 microm(2), p < 0.001). The surface area in sclerosing peritonitis (n = 1; 1,200 microm(2)) was greater than that of all the others. Giant cells were found in the 1 case with sclerosing peritonitis and in 3 of 9 cases with peritoneal sclerosis, although they were found in only 1 of 14 patients with peritoneal fibrosis and in none of those with pathologic acute peritonitis or normal peritoneum. As the surface area of mesothelial cells increased to more than 400 microm(2) and giant cells appeared in the effluent, the frequency of peritoneal sclerosis and/or clinical SEP increased. CONCLUSION: An increase in the mesothelial cell surface area and the emergence of giant cells in the effluent indicate advanced peritoneal histopathology, and may be useful indicators to determine appropriate timing of discontinuation of CAPD to prevent the development of SEP.

Adult↗
PubMed2001

Mechanical stimulation activates Galphaq signaling pathways and 5-hydroxytryptamine release from human carcinoid BON cells.

5-Hydroxytryptamine (5-HT) released from enterochromaffin cells activates secretory and peristaltic reflexes necessary for lubrication and propulsion of intestinal luminal contents. The aim of this study was to identify mechanosensitive intracellular signaling pathways that regulate 5-HT release. Human carcinoid BON cells displayed 5-HT immunoreactivity associated with granules dispersed throughout the cells or at the borders. Mechanical stimulation by rotational shaking released 5-HT from BON cells or from guinea pig jejunum during neural blockade with tetrodotoxin. In streptolysin O-permeabilized cells, guanosine 5'-O- (2-thiodiphosphate) (GDP-beta-S) and a synthetic peptide derived from the COOH terminus of Galphaq abolished mechanically evoked 5-HT release, while the NH(2)-terminal peptide did not. An antisense phosphorothioated oligonucleotide targeted to a unique sequence of Galphaq abolished mechanically evoked 5-HT release and reduced Galphaq protein levels without affecting the expression of Galpha(11). Depletion and chelation of extracellular calcium did not alter mechanically evoked 5-HT release, whereas depletion of intracellular calcium stores by thapsigargin and chelation of intracellular calcium by 1,2-bis (o-Aminophenoxy) ethane-N,N,N',N'-tetraacetic acid tetra (acetoxymethyl) ester (BAPTA-AM) reduced 5-HT release. Mechanically evoked 5-HT release was inhibited by somatostatin-14 in a concentration-dependent manner. The results suggest that mechanical stimulation of enterochromaffin-derived BON cells directly or indirectly stimulates a G protein-coupled receptor that activates Galphaq, mobilizes intracellular calcium, and causes 5-HT release.

Bacterial Proteins↗
PubMed2001

Evaluation of electromyographic monitoring during insertion of thoracic pedicle screws.

We prospectively studied the use of intercostal EMG monitoring as an indicator of the accuracy of the placement of pedicle screws in the thoracic spine. We investigated 95 thoracic pedicles in 17 patients. Before insertion of the screw, the surgeon recorded his assessment of the integrity of the pedicle track. We then stimulated the track using a K-wire pedicle probe connected to a constant current stimulator. A compound muscle action potential (CMAP) was recorded from the appropriate intercostal or abdominal muscles. Postoperative CT was performed to establish the position of the screw. The stimulus intensity required to evoke a muscle response was correlated with the position of the screw on the CT scan. There were eight unrecognised breaches of the pedicle. Using 7.0 mA as a threshold, the sensitivity of EMG was 0.50 in detecting a breached pedicle and the specificity was 0.83. Thoracic pedicle screws were accurately placed in more than 90% of patients. EMG monitoring did not significantly improve the reliability of placement of the screw.

Adult↗
PubMed2001

Butyltin compounds in sediments from the commercial harbor of Alexandria City, Egypt.

Tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT) compounds were quantitatively determined in surface-sediment samples collected from 23 sites in the commercial harbor of Alexandria City, Egypt. Butyltin concentrations in sediments varied widely depending on the sample location, ranging from less than 0.1 to 186 ng g(-1) of Sn for MBT, less than 0.1 to 379 ng g(-1) of Sn for DBT, and 1 to 2,067 ng g(-1) of Sn for TBT Elevated TBT concentrations, ranging from 727 to 2,067 ng g(-1) of Sn were observed in harbors, marinas, and near ship-repair facilities, indicating that the butyltin-containing, antifouling paints of boats and vessels are the major source of butyltin contamination. The TBT concentration decreased rapidly away from potential source areas of boat docking and repair facilities. The high relative concentrations of TBT in the sediments indicated that degradation processes in the sediments are minor, probably due to the anoxic sedimentary conditions at the sampling sites and/or relatively fresh input of TBT to these sites.

Biodegradation, Environmental↗
PubMed2001

Immunochemical characterization of brain and pineal tryptophan hydroxylase.

Recombinant mouse tryptophan hydroxylase (TPH) was expressed in Escherichia coli, using a bacterial expression vector and has been purified to homogeneity by sonication followed by Sepharose 4B column chromatography and native slab gel electrophoresis. This purified enzymatically active TPH protein was used for production of a specific antiserum. This antiserum identified the predicted TPH band (molecular weight, 54 kDa) on Western blot of crude extracts from the rat and mouse dorsal raphe, and the rat pineal gland. However, this antiserum recognized an additional protein band of lower molecular weight (48 kDa) in pineal extract. It is not clear whether the 48 kDa TPH band represents an isozyme or a protease cleavage product of TPH. Since the pineal gland contains higher TPH mRNA and lower TPH activity when it is compared with dorsal raphe nucleus enzyme, this lower molecular weight TPH may participate in the reduced TPH specific activity. In addition, there are no specific TPH inhibitors in the pineal gland and this lower molecular weight TPH is inactive or has a very low specific activity. This antiserum specifically immunostained serotonergic cell bodies in the dorsal raphe nuclei, some large caliber serotonergic processes in the dorsal raphe area as well as terminals in the olfactory bulb. It also immunolabeled the pineal gland and immunoprecipitated equally well TPH protein from the dorsal raphe nucleus and the pineal gland in a concentration-dependent manner.

Animals↗
PubMed2000

Identification of novel genes differentially expressed in PMA-induced HL-60 cells using cDNA microarrays.

Identification of normal growth and differentiation-inducing proteins and their interaction in normal development have made it possible to elucidate the molecular basis of normal development and the mechanisms uncoupling growth and differentiation during tumor development. The development of cancer and the experimental reversal of tumorigenicity are accompanied by complex changes in patterns of gene expression. cDNA microarrays provide a powerful tool for studying these phenomena. In the present study, a high-density microarray of human cDNA elements was used to search for differences in gene expression associated with differentiation of human promyelic leukemia HL-60 cells. Microarrays containing 3,063 human cDNAs were printed on glass slides with high-speed robotics. These DNA 'chips' were used to quantitatively monitor differential expression of the cognate human genes using a highly sensitive two-color hybridization assay. The identification of known and novel phorbol ester-regulated genes in hematopoietic progenitor cells demonstrates the sensitivity of the assay.

Base Sequence↗
PubMed2000

Varying expression levels of colony stimulating factor receptors in disease states and different leukocytes.

Administration of G-CSF may not always respond in rise of neutrophil counts in different patient population. In order to understand a possible inter-relationship between the G-CSF and GM-CSF induced leukocyte responses and expression levels of receptors for G-CSF (G-CSFr) and GM-CSF (GM-CSFr), the levels of each receptor and CSF were measured in patients with basophilia (8), eosinophilia (14) and bacterial infection showing neutrophilia (12) in comparison with normal healthy adults (12) and children (14). G-CSFr was expressed in neutrophils in the largest amount followed by monocytes, but GM-CSFr was expressed more in monocytes than neutrophils. Lymphocytes and basophils did not express G-CSFr or GM-CSFr. The amount of GM-CSFr in neutrophils was present less in patients with infection than normal control (P = 0.031). The neutrophils expressed more G-CSFr than GM-CSFr. The quantity of G-CSFr in eosinophil showed marked interval change, higher in acute stage. The plasma concentrations of G-CSF in patients with infection were much higher than normal adults or children (117.95 +/- 181.16 pg/ml, P < 0.05). Binding assay with excess amount of CSFs could discriminate the patient who did not show any response to G-CSF or GM-CSF administration. After incubation with excess CSFs, more receptors were blocked in children than in adults (G-CSF P = 0.024, GM-CSF P = 0.006). These results indicate that the amount of CSFr in leukocyte varies in different types of leukocyte, and changes according to the patients' condition even in the same type of leukocyte, and the CSFrs of children bind to CSFs more than those of adults.

Adult↗
PubMed2000

Identification of the self-interaction of rat TCTP/IgE-dependent histamine-releasing factor using yeast two-hybrid system.

To further understand the biological function of translationally controlled tumor protein (TCTP), also known as IgE-dependent histamine-releasing factor (HRF), the yeast two-hybrid system was used to screen interacting molecules. We isolated cDNA clones coding for TCTP/HRF, suggesting that it may have a self-interacting property. Domain mapping of the interaction revealed that the C-terminal region of residue 126-172 is involved in self-interaction. The self-interacting property of TCTP/HRF was further supported by FPLC gel-filtration chromatography and coimmunoprecipitation analysis from transfected COS-7 cells. Our data suggests that TCTP/HRF may have a potential to self-interact through the C-terminal region, and the self-interaction property may be related to its biological function.

Animals↗
PubMed2000

Expression, purification, and characterization of gp160e, the soluble, trimeric ectodomain of the simian immunodeficiency virus envelope glycoprotein, gp160.

The envelope glycoprotein, gp160, of simian immunodeficiency virus (SIV) shares approximately 25% sequence identity with gp160 from the human immunodeficiency virus, type I, indicating a close structural similarity. As a result of binding to cell surface CD4 and co-receptor (e.g. CCR5 and CXCR4), both SIV and human immunodeficiency virus gp160 mediate viral entry by membrane fusion. We report here the characterization of gp160e, the soluble ectodomain of SIV gp160. The ectodomain has been expressed in both insect cells and Chinese hamster ovary (CHO)-Lec3.2.8.1 cells, deficient in enzymes necessary for synthesizing complex oligosaccharides. Both the primary and a secondary proteolytic cleavage sites between the gp120 and gp41 subunits of gp160 were mutated to prevent cleavage and shedding of gp120. The purified, soluble glycoprotein is shown to be trimeric by chemical cross-linking, gel filtration chromatography, and analytical ultracentrifugation. It forms soluble, tight complexes with soluble CD4 and a number of Fab fragments from neutralizing monoclonal antibodies. Soluble complexes were also produced of enzymatically deglycosylated gp160e and of gp160e variants with deletions in the variable segments.

Animals↗