[Show abstract][Hide abstract] ABSTRACT: Similar to humans, most of non-human primates also contain the ABO blood group system. In this study, we sought to evaluate the ABO antibody (Ab) levels in monkeys using a modified flow cytometry method (FCM). The standard commercial human A or B-red blood cells (RBCs) were used as target cells. The binding of target cells and anti-A or B blood group Ab in sera of rhesus or cynomolgus monkeys was detected by flow cytometry after adding secondary specific fluorescence-labeled anti-human IgG or IgM Ab. Human healthy blood donor sera were used as controls. The results revealed that, using clear monkey sera, which were pre-absorbed on normal human type O RBCs to remove non-specific anti-human Abs, the modified FCM gave an accurate detection of ABO Ab levels in monkeys. When compared with the results of human sera, the distribution of ABO Ab levels in monkey sera were significantly lower (P<0.05). We concluded that the modified FCM could be used for the detection of monkey ABO Ab levels. The technique and data will be very valuable for the future establishment of ABO-incompatible organ transplant models in non-human primates, which could improve clinical applications.
Zoological Research 02/2011; 32(1):56-61. DOI:10.3724/SP.J.1141.2011.01056
[Show abstract][Hide abstract] ABSTRACT: A new L-amino acid oxidase (designated as DRS-LAAO) was purified from Daboia russellii siamensis venom by ion-exchange, gel filtration and affinity chromatographies. DRS-LAAO is a homodimeric enzyme with a molecular weight of 120.0 kDa as measured by size exclusion chromatography and the monomeric molecular weight of 58.0 kDa as measured by SDS-PAGE under both non-reducing and reducing conditions. The N-terminal amino acid sequence (ADDKNPLEECFREDD) of DRS-LAAO shares high identity with other snake venom L-amino acid oxidases, especially with those isolated from viperid venoms. The enzyme displayed high specificity towards hydrophobic L-amino acids. The best substrate of DRS-LAAO was L-Leu followed by L-Phe and L-Ile, while five substrates--L-Pro, L-Asn, L-Gly, L-Ser and L-Cys were not oxidized. Optimal pH of DRS-LAAO was 8.8. The enzyme showed no hemorrhagic activity even at a dosage of 55.0 microg. DRS-LAAO dose-dependently inhibited platelet aggregation induced by ADP (83.33 microM) and TMVA (55.0 nM) with an IC(50) value of 32.8 microg/ml and 32.3 microg/ml, respectively. The minimum inhibitory concentrations (MICs) of DRS-LAAO against Staphylococci aureus (ATCC 25923), Pseudomonas aeruginosa (ATCC 27853) and Escherichia coli (ATCC 25922) were 9.0, 144.0 and 288.0 microg/ml, respectively. The minimum bactericidal concentrations (MBCs) of the enzyme for these strains were twice of the MIC values. These results showed that DRS-LAAO had the strongest antimicrobial activity against S. aureus among these three international standard stains. Antibacterial-activities of DRS-LAAO against eight clinical methicillin-resistant Staphylococcus aureus (MRSA) isolates were also tested. The MICs of DRS-LAAO against these isolates ranged from 4.5 to 36.0 microg/ml. And the MBCs of the enzyme against these isolates ranged from 9.0 to 72.0 microg/ml.
[Show abstract][Hide abstract] ABSTRACT: Cobra venom factor (CVF) depletes complement C3 and may therefore be important in preventing the complement-mediated damage and disease. In comparison with various CVF reported previously, Yunnan-cobra venom factor (Y-CVF) has higher anticomplement activity. The goal for this research is to investigate whether Y-CVF could induce the specific neutralized anti-Y-CVF antibody and xenoantibodies in non-human primates. Thus two cynomolgus monkeys were intravenously injected with Y-CVF (0.05 mg/kg) every two weeks for totally four times. The serum C3, CH50, anti-Y-CVF antibody and xenoantibody levels were measured at different time points before and after Y-CVF injection. The results revealed that, complement C3 was effectively depleted during the first two injections, and incompletely depleted during the third injection, but almost not depleted during the last injection. The results of Western blot and ELISA confirmed the production of anti-Y-CVF antibody, and its titer increased with the injection. Additionally no significant changes of anti-porcine endothelia cell xenoantibodies were found measured by flow cytometry. We concluded that multiple injection of Y-CVF stimulated anti-Y-CVF antibody production in monkeys, which resulted in the invalid of Y-CVF. The induction of anti-alpha -Gal xenoantibody by Y-CVF in primates was not observed.
[Show abstract][Hide abstract] ABSTRACT: Monkeys do not express ABO antigens on red blood cells (RBCs), but on tissues, which is an obstacle in ABO typing. In this study we describe a simple and efficient method to type monkeys blood. Rhesus monkeys (n=34) and cynomolgus monkeys (n=16) were typed by the direct and reverse gel system, which has been widely used in clinics in recent years. Based on the results of immunohistochemical staining, we evaluated the feasibility and the interference factors of the gel system to type monkeys. The results revealed that the direct gel system didn’t have a positive report, the fibrinogen and non-specific anti-human antibodies in monkey blood interfered with the reverse gel system in some samples. In accordance with the results of immunohistochemical staining, using clear sera, which were pre-absorbed on normal human type O RBCs, the reverse gel system gave an accurate blood type determination for monkeys. We concluded that the reverse gel system could be used for ABO typing of monkeys, and the fibrinogen and non-specific anti-human antibodies were the major interference factors, which could be eliminated by using clear and pre-absorbed sera.
[Show abstract][Hide abstract] ABSTRACT: Group IIA phospholipase A(2) (PLA(2)) are major components in Viperidae/Crotalidae venom. In the present study, a novel PLA(2) named promutoxin with Arg at the site 49 has been purified from the venom of Protobothrops mucrosquamatus by chromatography. It consists of 122 amino acid residues with a molecular mass of 13,656 Da assessed by MALDI-TOF. It has the structural features of snake venom group IIA PLA(2)s, but has no PLA(2) enzymatic activity. Promutoxin shows higher amino acid sequence identity to the K49 PLA(2)s (72-95%) than to D49 PLA(2)s (52-58%). Promutoxin exhibits potent myotoxicity in the animal model with as little as 1 microg of promutoxin causing myonecrosis and myoedema in the gastrocnemius muscle of mice. Promutoxin is also able to stimulate the release of IL-12, TNFalpha, IL-6 and IL-1beta from human monocytes, and induce IL-2, TNFalpha and IL-6 release from T cells, indicating that this snake venom group IIA PLA(2) is actively involved in the inflammatory process in man caused by snake venom poisoning.
[Show abstract][Hide abstract] ABSTRACT: To investigate the effect of Yunnan-cobra venom factor (Y-CVF) in overcoming acute humoral rejection after allograft cardiac transplantation in presensitized recipients.
Fifteen Lewis rats received the transplantation of full-thickness skin graft of BN rats three times so as to be presensitized. Fifteen pairs of Lewis rat, as recipients of heart, and BN rat, as heart donors, were randomly divided into 2 groups: experimental group (n = 8), and control group (n = 7). The Lewis rats in the experimental group received heart transplantation of the heart of the BN rat 7 approximately 10 days after the third skin transplantation, and were injected with Y-CVF 80 microg/kg 24 hours before the heart transplantation. The Lewis rat in the control group received only the heart transplantation without Y-CVF injection. Blood samples were collected from all rats before pre-sensitization and 7 days after the third skin transplantation so as to determine the titer of anti-BN rat lymphocyte antibody. 0 and 24 hours, and 6 and 8 days after Y-CVF injection blood samples were collected from the Lewis rats to determine the total complement activity with the complement activity before Y-CVF injection defined as 100%. The survival time of the transplanted heart was observed. After the transplanted hearts stopped to beat, they were resected and underwent HE staining and microscopy. Immunohistochemistry was used to examine the deposition of IgG and complement 3 (C3).
The titer of anti-BN rat lymphocyte antibody was 0 before the pre-sensitization, and increased to 1:1028 - 1:2056 7 days after the third skin pre-sensitization. The serum total complement activity of the Lewis rats decreased to 0 twenty-four hours after the Y-CVF injection, recovered to 2.01% - 15.41% 6 days after, and returned to the normal level (89.61% - 109.46%) 8 days after. The mean survival time of the transplanted hearts of the control group was 12.71 +/- 13.94 hours (with a range of 1.5 - 15 hours), significantly shorter than that of the experimental group (99.50 +/- 38.72 hours, with a range of 23 - 153 hours, P < 0.01). Pathological examination showed that the acute humoral rejection in the control group was mainly complement-dependent antibody-mediated humoral rejection characterized by intravascular thrombosis, and that in the experimental group was mainly cellular rejection, characterized by extensive infiltration of mononuclear cells. Immunohistochemistry showed that remarkable IgG deposition was seen in the cardiac muscle cells and vascular endothelial cells in both groups; however, C3 deposition in vascular endothelial cells could be seen only in the control group.
Administration of CVF is effective in overcoming the acute humoral rejection after allograft cardiac transplantation in presensitized recipients.
[Show abstract][Hide abstract] ABSTRACT: A novel phospholipase A2 (PLA2) with Asn at its site 49 was purified from the snake venom of Protobothrops mucrosquamatus by using SP-Sephadex C25, Superdex 75, Heparin-Sepharose (FF) and HPLC reverse-phage C18 chromatography and designated as TM-N49. It showed a molecular mass of 13.875 kDa on MALDI-TOF. TM-N49 does not possess enzymatic, hemolytic and hemorrhagic activities. It fails to induce platelet aggregation by itself, and does not inhibit the platelet aggregation induced by ADP. However, it exhibits potent myotoxic activity causing inflammatory cell infiltration, severe myoedema, myonecrosis and myolysis in the gastrocnemius muscles of BALB/c mice. Phylogenetic analysis found that that TM-N49 combined with two phospholipase A2s from Trimeresurus stejnegeri, TsR6 and CTs-R6 cluster into one group. Structural and functional analysis indicated that these phospholipase A2s are distinct from the other subgroups (D49 PLA2, S49 PLA2 and K49 PLA2) and represent a unique subgroup of snake venom group II PLA2, named N49 PLA2 subgroup.
[Show abstract][Hide abstract] ABSTRACT: A novel C-type lectin-like protein, dabocetin, was purified from Daboia russellii siamensis venom. On SDS-polyacrylamide gel electrophoresis, it showed a single band with an apparent molecular weight of 28 kDa and two distinct bands with the apparent molecular weights of 15.0 kDa and 14.5 kDa under non-reducing and reducing conditions, respectively. cDNA clones containing the coding sequences for dabocetin alpha and beta subunits were isolated and sequenced. The deduced protein sequences of both subunits were confirmed by N-terminal amino acid sequencing and trypsin-digested peptide mass fingerprinting. Dabocetin did not induce platelet aggregation in platelet-rich plasma. It also had little effect on the platelet aggregation induced by ADP, TMVA or stejnulxin. Whereas, dabocetin inhibited ristocetin-induced platelet agglutination in platelet-rich plasma in a dose-dependent manner with an IC50 value of 0.35 microM. Flow cytometry analysis showed that dabocetin significantly inhibited mAb SZ2 binding to platelet membrane glycoprotein Ib alpha, indicating that platelet membrane glycoprotein Ib is involved in the inhibitory effect of dabocetin on ristocetin-induced platelet agglutination.
[Show abstract][Hide abstract] ABSTRACT: Poisonous snakebite wound is a popular disease worldwide. However, the pathogenesis remains unclear. In the present study, a novel metalloproteinase atrahagin in Chinese cobra (Naja atra) snake venom was purified, using heparin-sepharose followed by Superdex 75 gel filtration chromatography. Apart from its alpha-fibrinogenase activity, atrahagin potently activated human colon, lung and tonsil mast cells with the net histamine release being 25.9+/-4.4, 17.0+/-1.9, 13.2+/-3.6%, respectively. Time course studies revealed that the peak histamine release induced by atrahagin occurred at 12, 12 and 8 min following incubation of the enzyme with colon, lung and tonsil mast cells, respectively. The response of mast cells to atrahagin was abolished by preincubation of the cells with metabolic inhibitors or pertussis toxin, and by removal of Ca2+ and Mg2+ from the challenge buffer. In conclusion, activation of human mast cells by atrahagin indicated that the enzyme might contribute to the pathogenesis of snakebite wound.
The International Journal of Biochemistry & Cell Biology 02/2006; 38(4):510-20. DOI:10.1016/j.biocel.2005.10.011 · 4.24 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Jerdostatin represents a novel RTS-containing short disintegrin cloned by reverse transcriptase-PCR from the venom gland mRNA of the Chinese Jerdons pit viper Trimeresurus jerdonii. The jerdostatins precursor cDNA contained a 333-bp open reading frame encoding a signal peptide, a pre-peptide, and a 43-amino acid disintegrin domain, whose amino acid sequence displayed 80% identity with that of the KTS-disintegrins obtustatin and viperistatin. The jerdostatin cDNA structure represents the first complete open reading frame of a short disintegrin and points to the emergence of jerdostatin from a short-coding gene. The different residues between jerdostatin and obtustatin/viperistatin are segregated within the integrin-recognition loop and the C-terminal tail. Native jerdostatin (r-jerdostatin-R21) and a R21K mutant (r-jerdostatin-K21) were produced in Escherichia coli. In each case, two conformers were isolated. One-dimensional (1)H NMR showed that conformers 1 and 2 of r-jerdostatin-R21 represent, respectively, well folded and unfolded proteins. The two conformers of the wild-type and the R21K mutant inhibited the adhesion of alpha(1)-K562 cells to collagen IV with IC(50) values of 180 and 703 nm, respectively. The IC(50) values of conformers 2 of r-jerdostatin-R21 and r-jerdostatin-K21 were, respectively, 5.95 and 12.5 microm. Neither r-jerdostatin-R21 nor r-jerdostatin-K21 showed inhibitory activity toward other integrins, including alpha(IIb)beta(3), alpha(v)beta(3), alpha(2)beta(1), alpha(5)beta(1), alpha(4)beta(1), alpha(6)beta(1), and alpha(9)beta(1) up to a concentration of 24 mum. Although the RTS motif appears to be more potent than KTS inhibiting the alpha(1)beta(1) integrin, r-jerdostatin-R21 is less active than the KTS-disintegrins, strongly suggesting that substitutions outside the integrin-binding motif and/or C-terminal proteolytic processing are responsible for the decreased inhibitory activity.
[Show abstract][Hide abstract] ABSTRACT: Jerdostatin represents a novel RTS-containing short disintegrin cloned by reverse transcriptase-PCR from the venom gland mRNA
of the Chinese Jerdons pit viper Trimeresurus jerdonii. The jerdostatins precursor cDNA contained a 333-bp open reading frame encoding a signal peptide, a pre-peptide, and a 43-amino
acid disintegrin domain, whose amino acid sequence displayed 80% identity with that of the KTS-disintegrins obtustatin and
viperistatin. The jerdostatin cDNA structure represents the first complete open reading frame of a short disintegrin and points
to the emergence of jerdostatin from a short-coding gene. The different residues between jerdostatin and obtustatin/viperistatin
are segregated within the integrin-recognition loop and the C-terminal tail. Native jerdostatin (r-jerdostatin-R21) and a
R21K mutant (r-jerdostatin-K21) were produced in Escherichia coli. In each case, two conformers were isolated. One-dimensional 1H NMR showed that conformers 1 and 2 of r-jerdostatin-R21 represent, respectively, well folded and unfolded proteins. The
two conformers of the wild-type and the R21K mutant inhibited the adhesion of α1-K562 cells to collagen IV with IC50 values of 180 and 703 nm, respectively. The IC50 values of conformers 2 of r-jerdostatin-R21 and r-jerdostatin-K21 were, respectively, 5.95 and 12.5 μm. Neither r-jerdostatin-R21 nor r-jerdostatin-K21 showed inhibitory activity toward other integrins, including αIIbβ3, αvβ3, α2β1, α5β1, α4β1, α6β1, and α9β1 up to a concentration of 24 μm. Although the RTS motif appears to be more potent than KTS inhibiting the α1β1 integrin, r-jerdostatin-R21 is less active than the KTS-disintegrins, strongly suggesting that substitutions outside the
integrin-binding motif and/or C-terminal proteolytic processing are responsible for the decreased inhibitory activity.
Journal of Biological Chemistry 12/2005; 280(49):40714-40722. · 4.60 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A fibrinogen-clotting enzyme designed as jerdonobin-II was isolated from the venom of Trimeresurus jerdonii. It differed in molecular weight and N-terminal sequence with the previously isolated jerdonobin, a thrombin-like enzyme from the same venom. The enzyme consists of a single polypeptide chain with molecular weights of 30,000 and 32,000 under non-reducing and reducing conditions, respectively. Jerdonobin-II showed weak fibrinogen clotting activity and its activity unit on fibrinogen was calculated to be less than one unit using human thrombin as standard. The precursor protein sequence of jerodonobin-II was deduced from cloned cDNA sequence. The sequence shows high similarity (identity=89%) to TSV-PA, a specific plasminogen activator from venom of T. stejnegeri. Despite of the sequence similarity, jerdonobin-II was found devoid of plasminogen activating effect. Sequence alignment analysis suggested that the replacement of Lys239 in TSV-PA to Gln239 in jerdonobin-II might play an important role on their plasminogen activating activity difference.
[Show abstract][Hide abstract] ABSTRACT: To investigate the mechanisms of purified cobra venom factor (CVF) in preventing hyperacute rejection (HAR) and prolonging recipient survival following discordant liver xenotransplantation in rats.
All animals were divided into two groups, group I (n = 20), unmodified recipients as control; group II (n = 20), xenograft recipients were treated with 50 microg/kg CVF i.v. on day-1. The pathologic changes of liver were observed and TNF-alpha of blood serum was detected.
Recipient survival after CVF treatment is significantly prolonged compared with unmodified recipients (1.8 +/- 0.6 vs.7.4 +/- 2.1 h, P < 0.01). Histologically, widespread thrombosis, interstitial haemorrhage, C3 deposits on sinusoids and central veins characterized xenografts of the control group. Xenografts of the CVF group showed endothelium swelling and cellular infiltrate, no deposit of C3 was detected.
Purified CVF can prevent guinea pig-to-rat liver xenografts from HAR and extend recipient survival. Preconditioning with CVF, guinea pig-to-rat combination is a useful life-supporting model to explore further mechanisms of discordant liver xenotransplantation.
[Show abstract][Hide abstract] ABSTRACT: TMVA is a C-type lectin-like protein with potent platelet activating activity from Trimeresurus mucrosquamatus venom. In the absence of von Willebrand factor (vWF), TMVA dose-dependently induced aggregation of washed platelets. Anti-GP Ib monoclonal antibodies (mAbs), HIP1, specifically inhibited TMVA-induced aggregation in a dose-dependent manner. The aggregation was also inhibited by mAb P2 (an anti-GP IIb mAb). Flow cytometric analysis revealed that FITC-TMVA bound to human formalin-fixed platelets in a saturable manner, and its binding was specifically blocked by HIP1 in a dose-dependent manner. Flow cytometric analysis showed that TMVA did not bind to platelet GPIX, GPIIb, GPIIIa, GPIa, GPIIa and GPIV. Moreover, the platelet aggregation induced by TMVA was partially inhibited when platelet was pretreated with mocarhagin, a snake venom protease that specifically cleaves human GPIb. These results suggest that TMVA is a strong platelet agonist via GPIb and it might have multiple functional binding-sites on GPIb molecule or on other unknown receptor.
[Show abstract][Hide abstract] ABSTRACT: A novel disintegrin, jerdonatin, was purified to homogeneity from Trimeresurus jerdonii venom by gel filtration and reversed-phase high-pressure liquid chromatography. We isolated the cDNA encoding jerdonatin from the snake venom gland. Jerdonatin cDNA precursor encoded pre-peptide, metalloprotease and disintegrin domain. Jerdonatin is composed of 72 amino acid residues including 12 cysteines and the tripeptide sequence Arg-Gly-Asp (RGD), a well-known characteristic of the disintegrin family. Molecular mass of jerdonatin was determined to be 8011 Da by matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS). Jerdonatin inhibited ADP- and collagen-induced human platelet aggregation with IC50 of 123 and 135 nM, respectively. We also investigated the effect of jerdonatin on the binding of B6D2F1 hybrid mice spermatozoa to mice zona-free eggs and their subsequent fusion. Jerdonatin significantly inhibited sperm-egg binding in a concentration-dependent manner, but had no effect on the fusion of sperm-egg. These results indicate that integrins on the egg play a role in mammalian fertilization.
Comparative Biochemistry and Physiology Part B Biochemistry and Molecular Biology 10/2004; 139(1):117-22. DOI:10.1016/j.cbpc.2004.06.012 · 1.90 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A hemorrhagic proteinase, jerdohagin, was purified from Trimeresurus jerdonii venom by gel filtration and ion-exchange chromatographies. It was a single chain polypeptide with an apparent molecular weight of 96 kDa as estimated by SDS-PAGE under the non-reducing and reducing conditions. Internal peptide sequencing indicated that it consisted of metalloproteinase, disintegrin-like and cysteine-rich domains and belonged to the class III snake venom metalloproteinases (class P-III SVMPs). Like other typical metalloproteinases, hemorrhagic activities of jerdohagin were completely inhibited by EDTA, but not by PMSF. Jerdohagin preferentially degraded alpha-chain of human fibrinogen. Interestingly, jerdohagin did not activate human prothrombin, whereas it cleaved human prothrombin and fragment F1 of activated human prothrombin.
[Show abstract][Hide abstract] ABSTRACT: In xenotransplantation, donor endothelium is the first target of immunological attack. Activation of the endothelial cell by preformed natural antibodies leads to platelet binding via the interaction of the glycoprotein (GP) Ib and von Willebrand factor (vWF). TMVA is a novel GPIb-binding protein purified from the venom of Trimeresurus mucrosquamatus. In this study, the inhibitory effect of TMVA on platelet aggregation in rats and the effect on discordant guinea pig-to-rat cardiac xenograft survival were investigated. Three doses (8, 20 or 40 microg/kg) of TMVA were infused intravenously to 30 rats respectively. Platelet aggregation rate was assayed 0.5, 12, and 24 h after TMVA administration. Wister rats underwent guinea pig cardiac cervical heterotopic transplantation using single dosing of TMVA (20 microg/kg, i.v., 0.5 h before reperfusion). Additionally, levels of TXB(2) and 6-keto-PGF(1alpha) within rejected graft tissues were determined by radioimmunoassay. Treatment with TMVA at a dose of 20 or 40 microg/kg resulted in complete inhibition of platelet aggregation 0.5 h after TMVA administration. Rats receiving guinea pig cardiac xenografts after TMVA therapy had significantly prolonged xenograft survival. Histologic and immunopathologic analysis of cardiac xenografts in TMVA treatment group showed no intragraft platelet microthrombi formation and fibrin deposition. Additionally, the ratio of 6-keto-PGF(1alpha) to TXB(2) in TMVA treatment group was significantly higher than those in control group. We conclude that the use of this novel GPIb-binding protein was very effective in preventing platelet microthrombi formation and fibrin deposition in a guinea pig-to-rat model and resulted in prolongation of xenograft survival. The increased ratio of PGI(2)/TXA(2) in TMVA treatment group may protect xenografts from the endothelial cell activation and contribute to the prolongation of xenograft survival.
[Show abstract][Hide abstract] ABSTRACT: At present, acute vascular rejection (AVR) remains a primary obstacle inhibiting long-term graft survival in the pig-to-non-human primate transplant model. The present study was undertaken to determine whether repetitive injection of low dose Yunnan-cobra venom factor (Y-CVF), a potent complement inhibitor derived from the venom of Naja kaouthia can completely abrogate hemolytic complement activity and subsequently improve the results in a pig-to-rhesus monkey heterotopic heart transplant model. Nine adult rhesus monkeys received a heterotopic heart transplant from wild-type pigs and the recipients were allocated into two groups: group 1 (n = 4) received repetitive injection of low dose Y-CVF until the end of the study and group 2 (n = 5) did not receive Y-CVF. All recipients were treated with cyclosporine A (CsA), cyclophosphamide (CyP) and steroids. Repetitive Y-CVF treatment led to very dramatic fall in CH50 and serum C3 levels (CH50 < 3 units/C3 remained undetectable throughout the experiment) and successfully prevented hyperacute rejection (HAR), while three of five animals in group 2 underwent HAR. However, the continuous suppression of circulating complement did not prevent AVR and the grafts in group 1 survived from 8 to 13 days. Despite undetectable C3 in circulating blood, C3 deposition was present in these grafts. The venular thrombosis was the predominant histopathologic feature of AVR. We conclude that repetitive injection of low dose Y-CVF can be used to continuously suppress circulating complement in a very potent manner and successfully prevent HAR. However, this therapy did not inhibit complement deposition in the graft and failed to prevent AVR. These data suggest that using alternative pig donors [i.e. human decay accelerating factor (hDAF)-transgenic] in combination with the systemic use of complement inhibitors may be necessary to further control complement activation and improve survival in pig-to-non-human primate xenotransplant model.
[Show abstract][Hide abstract] ABSTRACT: A chymotrypsin inhibitor, designated NA-CI, was isolated from the venom of the Chinese cobra Naja atra by three-step chromatography. It inhibited bovine alpha-chymotrypsin with a Ki of 25 nM. The molecular mass of NA-CI was determined to be 6403.8 Da by matrix-assisted laser-desorption ionization time-of-flight (MALDI-TOF) analysis. The complete amino acid sequence was determined after digestion of S-carboxymethylated inhibitor with Staphylococcus aureus V8 protease and porcine trypsin. NA-CI was a single polypeptide chain composed of 57 amino acid residues. The main contact site with the protease (P1) has a Phe, showing the specificity of the inhibitor. NA-CI shared great similarity with the chymotrypsin inhibitor from Naja naja venom (identities=89.5%) and other snake venom protease inhibitors.
Comparative Biochemistry and Physiology Part B Biochemistry and Molecular Biology 03/2004; 137(2):219-24. DOI:10.1016/j.cbpc.2003.11.007 · 1.90 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A novel disintegrin, jerdonin, was purified from the Trimeresurus jerdonii venom by means of gel filtration and reverse phase high pressure liquid chromatography. Its coding cDNA was also isolated from the venom gland. The jerdonin coding cDNA is part of a precursor composed of proprotein, metalloproteinase, and disintegrin domains. From the deduced amino acid sequence, jerdonin is composed of 71 amino acid residues including 12 cysteines and the tripeptide sequence Arg-Gly-Asp (RGD), a well-known characteristic of the disintegrin family. Molecular mass of jerdonin was determined to be 7483Da by matrix-assisted laser desorption ionization time of flight mass spectrometry. Jerdonin inhibited ADP- and collagen-induced human platelet aggregation with IC(50) of 220 and 240 nM, respectively. In vivo, jerdonin inhibited the growth of subcutaneously inoculated B16 solid tumor in C57BL/6 mice and improved the survival time of the tumor-bearing mice.