Nature of antigens and antibodies in immune complexes isolated by staphylococcal protein A from plasma of melanoma patients

Summary Immune complexes (IC) were isolated from plasma of melanoma patients by absorption to staphylococcal protein A and subsequent elution with MgCl₂. The isolated ICs were purified by precipitation with polyethylene glycol and sucrose density gradient ultracentrifugation after radioiodination with ¹²⁵I. The purified ICs were dissociated and radiolabeled antigen/antibody components were separated by ultracentrifugation at low pH (2.6). Under these conditions, about 72% radioactivity of the purified IC remained in the light-density region as a wide band. After neutralization, 26%–60% radioactivity in the region of 5S sedimentation bound to immobilized autologous immunoglobulins, as opposed to a maximum of 23% to immobilized immunoglobulins from human normal serum. Significant levels (73%–77%) of radioactivity in 7S region bound to rabbit anti-human IgG immunobeads. Immunoprecipitation of the antigen fraction by allogeneic anti-melanoma and rabbit anti-melanoma antibodies followed by SDS-polyacrylamide gel electrophoresis revealed the presence of a fetal antigen (FA) and a melanoma tumor-associated antigen (TAA). In addition, the presence of auto-antigen(s) was indicated by using autologous antibody in immunoprecipitation. Immunoglobulins (IgG) isolated from purified IC bound to cultured melanoma, sarcoma, and normal fibroblasts, although the binding to sarcoma and normal fibroblasts could be inhibited by preincubation of isolated IgG with soluble FA but not with soluble melanoma TAA. Thus, results of this investigation provide evidence that circulating IC in melanoma patients are composed of at least IgG and different antigens, and some of these antigens are produced by their tumor.     

Nature of antigens and antibodies in immune complexes isolated by staphylococcal protein A from plasma of melanoma patients

Immune complexes (IC) were isolated from plasma of melanoma patients by absorption to staphylococcal protein A and subsequent elution with MgCl2. The isolated ICs were purified by precipitation with polyethylene glycol and sucrose density gradient ultracentrifugation after radioiodination with 125I. The purified ICs were dissociated and radiolabeled antigen/antibody components were separated by ultracentrifugation at low pH (2.6). Under these conditions, about 72% radioactivity of the purified IC remained in the light-density region as a wide band. After neutralization, 26%-60% radioactivity in the region of 5S sedimentation bound to immobilized autologous immunoglobulins, as opposed to a maximum of 23% to immobilized immunoglobulins from human normal serum. Significant levels (73%-77%) of radioactivity in 7S region bound to rabbit anti-human IgG immunobeads. Immunoprecipitation of the antigen fraction by allogeneic anti-melanoma and rabbit anti-melanoma antibodies followed by SDS-polyacrylamide gel electrophoresis revealed the presence of a fetal antigen (FA) and a melanoma tumor-associated antigen (TAA). In addition, the presence of auto-antigen(s) was indicated by using autologous antibody in immunoprecipitation. Immunoglobulins (IgG) isolated from purified IC bound to cultured melanoma, sarcoma, and normal fibroblasts, although the binding to sarcoma and normal fibroblasts could be inhibited by preincubation of isolated IgG with soluble FA but not with soluble melanoma TAA. Thus, results of this investigation provide evidence that circulating IC in melanoma patients are composed of at least IgG and different antigens, and some of these antigens are produced by their tumor.     

Immunoassay of bovine and human low-density-lipoprotein receptors using monoclonal antibodies.

Two methods are described for the assay of low-density-lipoprotein (LDL) receptor protein based on the binding of receptor to microtitre plate wells coated with a specific monoclonal antibody or with LDL, followed by detection with radioactive antibody that recognizes a different part of the molecule. The two-antibody procedure detected approx. 2 ng of pure bovine receptor at twice background, and there was a linear relationship on a double-logarithm plot between radioactive antibody bound and the amount of receptor added, up to at least 500 ng of receptor protein per well. The procedure using immobilized LDL was less sensitive and the binding of receptor was inhibited by low concentrations of NaCl, which restricted its usefulness for routine assay of tissue extracts. LDL receptor protein could be readily assayed using the two-antibody procedure in normal human skin fibroblast extracts prepared by bulk-elution from small columns of DEAE-cellulose followed by rapid desalting. No radioactive antibody bound with extracts of cells from a receptor-negative familial hypercholesterolaemic subject. The LDL receptor content of normal fibroblasts preincubated with lipoprotein-deficient serum was estimated, using bovine receptor as standard, to be approx. 60 ng of receptor protein/mg of cell protein.     

Feasibility of protein A for the oriented immobilization of immunoglobulin on silicon surface for a biosensor with imaging ellipsometry

The feasibility of using protein A to immobilize antibody on silicon surface for a biosensor with imaging ellipsometry was presented in this study. The amount of human IgG bound with anti-IgG immobilized by the protein A on silicon surface was much more than that bound with anti-IgG immobilized by physical adsorption. The result indicated that the protein A could be used to immobilize antibody molecules in a highly oriented manner and maintain antibody molecular functional configuration on the silicon surface. High reproducibility of the amount of antibody immobilization and homogenous antibody adsorption layer on surfaces could be obtained by this immobilization method. Imaging ellipsometry has been proven to be a fast and reliable detection method and sensitive enough to detect small changes in a molecular monolayer level. The combination of imaging ellipsometry and surface modification with protein A has the potential to be further developed into an efficient immunoassay protein chip.     

Preparation of high-capacity supports containing protein G immobilized to porous silica

This study examined the preparation of high-capacity silica supports containing immobilized protein G. A maximum content of 39 mg protein G/g silica was obtained when using 100 Å pore size silica, followed by 33 mg/g for 50 Å silica and 9.3-24 mg/g for 300-4000 Å silica. The surface coverage of protein G increased with pore size, with a maximum level of 0.037 μmol/m² being obtained for 4000 Å silica. These supports gave comparable apparent activities (i.e., 30-47% binding to rabbit immunoglobulin G [IgG]), with the highest binding capacities (71-77 mg IgG/g silica) being obtained for 50-100 Å silica.     

Comparison of antibody functionality using different immobilization methods

This study investigates the influence of antibody immobilization methods on antigen capture. Adsorption and two surface chemistries, an aminosilane chemistry and a common heterobifunctional crosslinker (N-gamma-maleimidobutyryloxy-succinimide ester, GMBS), were compared and evaluated for their ability to immobilize antibodies and capture antigen. The role of protein A as an orienting protein scaffold component in each of these techniques was also evaluated. Through experimentation it was determined that the GMBS technique immobilized the highest amount of antibody and minimized nonspecific binding. For all techniques, the most functional antibodies were found to be those immobilized with protein A. Interestingly, the aminosilane technique demonstrated the highest antigen capture with antibody alone but also exhibited the highest level of nonspecific binding.     

Expression of a monoclonal antibody-defined aminoterminal epitope of human apoC-I on native and reconstituted lipoproteins

Nine distinct mouse monoclonal antibodies were produced in two fusions using holo-human very low density lipoprotein (VLDL) as antigen. On immunoblotting first with human VLDL and then with isolated human apoC-I, seven of the antibodies, representing three isotypes, manifested specificity for apoC-I. Two antibodies were directed against apoB. To assess whether the seven anti-apoC-I antibodies were directed against the same or distinctively different epitopes, cross-competition assays were performed wherein 125I-labeled monoclonal antibodies were made to compete with unlabeled antibodies for occupancy on immobilized VLDL-associated apoC-I. All antibodies cross-competed to varying extents implying that they were directed against closely spaced epitopes, but based on these experiments three different epitopes were defined. On immunoblotting with CNBr fragments, all of the epitopes were assigned to the CNBr I fragment of human apoC-I (amino acids 1-38) suggesting that the NH2-terminal region of apoC-I is more immunogenic in mice than other parts of the molecule when apoC-I is associated with VLDL. A competitive solid-phase radioimmunoassay (RIA) was developed employing one of the anti-apoC-I antibodies (A3-4). VLDL was adsorbed to plastic microtiter wells, and a limiting amount of the antibody was reacted with the adsorbed VLDL. The amount of monoclonal antibody that bound to the immobilized VLDL-apoC-I was determined with a 125I-labeled goat anti-mouse IgG antibody. The addition of competitor apoC-I complexed with lipids resulted in reduced binding of the anti-apoC-I antibody to the immobilized VLDL-apoC-I. Competitor complexes consisted of an artificial lipid emulsion (Intralipid) incubated with apoC-I at phospholipid/apoC-I ratios of 1:1 to 60:1 (w/w). As the lipid/protein ratios were increased, the competitive displacement curves produced by the complexes become progressively steeper, while isolated lipid-free apoC-I produced curves with very shallow slopes, suggesting that a conformation-dependent epitope was being probed. Other apoproteins (C-II, C-III, A-I, A-II, and E) whether lipid-free or complexed with lipids did not compete. Fractionation of the 30:1 apoC-I-Intralipid complex by gel permeation chromatography suggested that apoC-I bound to phospholipids was the most effective competitor. This was confirmed by testing of apoC-I-DMPC complexes, which yielded curves that paralleled those produced by apoC-I-Intralipid.(ABSTRACT TRUNCATED AT 400 WORDS)     

Extraction of thromboxane B2 from urine using an immobilized antibody column for subsequent analysis by gas chromatography-mass spectrometry

This paper describes an antibody affinity (immunoaffinity) column which, in one step, extracts and sufficiently purifies urinary thromboxane B2 (TXB2) for quantitative analysis by high resolution gas chromatography-negative ion chemical ionization-selected ion monitoring-mass spectrometry (HRGC-NICI-SIM-MS). Polyclonal TXB2 antibody from rabbit was partially purified using immobilized Staphylococcus aureus Protein A. The purified IgG fraction was then immobilized using an N-hydroxysuccimidyl silica gel. The resulting matrix bound 570 ng TXB2 per ml of gel. TXB2 was quantitatively eluted with acetonitrile-water (19:1). Columns constructed from the gel could be used repeatedly since binding capacity was reconstituted using 0.01 M phosphate buffer (pH 7.4) with no apparent loss of activity. Using these columns, urinary TXB2 was sufficiently purified in one step such that in subsequent analysis by HRGC-NICI-SIM-MS interference free chromatograms were observed.     

Protein G: a powerful tool for binding and detection of monoclonal and polyclonal antibodies

Protein G is an immunoglobulin (IgG)-binding bacterial cell wall protein recently isolated from group G streptococci. We have investigated the avidity of protein G for various monoclonal and polyclonal Ig of the IgG class, and compared it with the binding properties of protein A, the staphylococcal Fc-binding protein. Radiolabeled Ig were mixed with Sepharose-coupled protein G or protein A, and the amounts of radioactivity bound to the matrix-coupled bacterial proteins were determined. The avidity was found to be greater for protein G than for protein A for all examined Ig. Protein G bound all tested monoclonal IgG from mouse IgG1, IgG2a, and IgG3, and rat IgG2a, IgG2b, and IgG2c. In addition, polyclonal IgG from man, cow, rabbit, goat, rat, and mouse bound to protein G, whereas chicken IgG did not. The binding property of protein G was additionally exploited in the Western blot assay, in which iodine-labeled protein G was used successfully for the detection of a rat monoclonal antibody against ovalbumin, and for the detection of rabbit and goat polyclonal whole antisera against human urinary proteins. In these experimental situations, protein G was found to be a powerful reagent for the detection of IgG, and consequently the antigen against which these antibodies are directed.     

Enzyme kinetic assays with surface plasmon resonance (BIAcore) based on competition between enzyme and creatinine antibody

A procedure is described which allows the characterization of enzyme by a hybrid approach using an enzyme and an antibody. The presented method is related to the affinity determination of antibodies by the 'affinity in solution' procedure for BlAcore. The antibody is used as an indicator for the concentration of substrate, which is also the antigen. A mixture of enzyme, substrate and antibody is incubated, and an aliquot of this solution is injected periodically into a flowcell containing immobilized substrate, which is bound by the antibody, but not cleaved by the enzyme. The chosen initial concentration of substrate inhibits the binding of antibody to the immobilized substrate by 90%. During the enzymatic reaction, increased amounts of antibody bind to the surface, as the substrate concentration is decreased. With this method, the cleavage of creatinine with creatinine iminohydrolase (6 mU/ml) was monitored for up to 11 h. A recently developed monoclonal antibody against creatinine was used as the indicating protein. For the calculation of enzyme activity, the signals were compared with a calibration curve for inhibition of antibody binding to the chip by creatinine in solution.     

Binding of anti-band 3 autoantibody to oxidatively damaged erythrocytes. Formation of senescent antigen on erythrocyte surface by an oxidative mechanism

Incubation of human erythrocytes oxidized by iron catalysts, ADP/Fe3+ or xanthine/xanthine oxidase/Fe3+, with autologous IgG resulted in IgG binding as detected by enzyme immunoassay using protein A-beta-galactosidase conjugate. The binding of autologous IgG to ADP/Fe3(+)-treated erythrocytes maximized when the cells were treated with 1.8:0.1 mM ADP/Fe3+, and declined when treated above this concentration, suggesting that autologous IgG binds to moderately but not to excessively oxidized erythrocytes. The antibody involved in the binding was anti-Band 3, the autoantibody known to bind to aged erythrocytes, because isolated anti-Band 3 bound to the oxidized cells, but anti-Band 3-depleted autologous IgG did not. In addition, purified Band 3 inhibited the autologous IgG binding. Anti-alpha-galactosyl IgG, another natural antibody which has been reported to bind to aged erythrocytes, did not bind to the oxidized cells. Oxidation of membrane lipids, SH-groups of membrane proteins, and Hb of these cells was slight, but the cells contained an increased amount of membrane-bound native Hb, indicating that the oxidized cell membrane has an altered property. alpha-Tocopherol prevented the lipid oxidation and the subsequent IgG binding. Reduction of the oxidized erythrocytes with dithiothreitol resulted in a loss of the IgG binding. These results suggest that anti-Band 3 binding sites (Band 3 senescent antigen) are formed on moderately oxidized erythrocytes as a result of oxidation of membrane protein SH-groups which can be mediated by the membrane lipid oxidation and that formation of the anti-Band 3 binding sites on the oxidized cells is an essentially reversible membrane event which is linked to oxidation and restoration of the protein SH-groups.     

Quantitative assay of hepatitis B surface antigen by using surface plasmon resonance biosensor

We performed a basic experiment for the rapid, on-line, real-time measurement of hepatitis B surface antigen using a surface plasmon resonance biosensor. We immobilized anti-HBsAg (hepatitis B surface antigen) polyclonal antibody, as a ligand, to the dextran layer on a CM5 chip surface that had previously been activated byN-hydroxysuccinimide. A sample solution containing HBsAg was fed through a microfluidic channel, and the reflecting angle change due to the mass increase from the binding was detected. The binding characteristics between HBsAg and its polyclonal antibody followed the typical monolayer adsorption isotherm. When the entire immobilized antibody had interacted, no additional, non-specific binding occurred, suggesting the immunoreaction was very specific. The bound antigen per unit mass of the antibody was independent of the immobilized ligand density. No significant steric hindrance was observed at an immobilization density of approximately 17.6 ng/mm². The relationship between the HBsAg concentration in the sample solution and the antigen bound to the ligand was linear up to ca. 40 μg/mL. This linearity was much higher than that of the ELISA method. It appeared the antigen-antibody binding increased as the immobilized ligand density increased. In summary, this study showed the potential of this SPR biosensor-based method as a rapid, simple and multi-sample on-line assay. Once properly validated, it may serve as a more efficient method for HBsAg quantification for replacing the ELISA.     

再生丝素固定的酶标免疫传感器的研究

所研究的酶标免疫传感器是采用再生丝素将待测抗原 (兔IgG)固定在石墨电极表面 ,选用抗体 (山羊抗兔IgG HRP)与其识别结合。利用H₂O₂ 将抗原抗体结合的电位响应信号放大采用直接电位法检测IgG的浓度。该传感器测定IgG的最低浓度可达 1.2×10^-10 mol/L ,标准曲线的线形范围在4.1×10^-7～1.2×10^-10 mol/L ,回归方程为: E=-1049+721g[IgG],响应时间为 15s。通过电泳的方法加速抗原抗体的识别结合 ,反应时间由原来的 90min缩短到 3 0min。这种以固定化抗原结合酶标抗体量的多少作为检测抗原标准的新型酶标免疫传感器 ,在临床检测、环境监测、HLA个人身份鉴定等领域都有着广阔的应用前景。     

Isolation and characterization of a monoclonal antibody against pig kidney sodium- and potassium-activated ATPase

A hybridoma cell line producing mouse monoclonal antibody against pig kidney Na,K-ATPase was established. The antibody, named 38 (mAb38, IgG1), was purified from mouse ascites fluid by chromatography on a protein A-Sepharose column. Antigens immobilized on microplate wells with p-benzoquinone were used for titer assays. mAb38 cross-reacted with both dodecyloctaethyleneglycol monoether (C12E8)-solubilized enzyme and membranous sodium dodecyl sulfate (SDS)-treated enzyme from kidney with high affinity (50% binding = 0.6 nM). However, the antibody bound to neither alpha- nor beta-subunit separated by preparative SDS-polyacrylamide gel electrophoresis (PAGE). The stoichiometry of antibody binding to the purified enzyme was estimated to be about 0.86 mol of IgG per mol of alpha beta-protomer. Na,K-ATPase proteins were recovered from a column of mAb38-coupled Affi-Gel by elution with pH 3 buffer when C12E8-solubilized kidney enzyme or detergent extracts of brain microsomes were applied to it, confirming that the mAb is directed to Na,K-ATPase. mAb38 at saturation level concentrations had no effect on kidney Na,K-ATPase activity or on ouabain-sensitive Rb uptake in erythrocytes. In an immunofluorescence study, the antibody bound to intact erythrocytes much more strongly than control IgG1 (mAb50c), but the extent of the antibody binding to inside-out vesicles under hypotonic conditions was lower than that of the control. Most of the antibody binding activity remained when the kidney enzyme was treated with sialidase. These results suggest that this mAb38 was raised against an intact conformation of a cell-surface-exposed site of Na,K-ATPase.     

A high-density poly(ethylene glycol) polymer brush for immobilization on glass-type surfaces.

Label-free heterogeneous phase detection critically depends on the properties of the interfacial layer. We have obtained high-density monomolecular poly(ethylene glycol) (PEG) layers by solvent-free coupling of homo-bifunctional PEGs (2,000 g/mol) at 75 degrees C to silica surfaces silanized with glycidyloxipropyltrimethoxysilane (GOPTS). Characterization by ellipsometry and contact angles revealed that PEG layers up to 3.4 ng/mm2 with low roughness and flexibility were obtained. Specific and non-specific binding at these PEG surfaces was monitored by reflectometric interference spectroscopy (RIfS). No significant non-specific adsorption upon incubation of 1 mg/ml ovalbumin was detectable (< 10 pg/mm2), and 150 pg/mm2 upon incubation of 10% calf serum, less than 10% of the amount adsorbed to the solely silanized surfaces. The terminal functional groups of the PEG layers were utilized to couple ligands and a protein. Specific protein interaction with these immobilized compounds was detected with saturation loadings in the range of protein monolayers (2-4 ng/mm2). The excellent functional properties, the high stability of the layers, the generic and practical coupling procedure and the versatility for immobilizing compounds of very different functionality make these PEG layers very attractive for application in label-free detection with silica or metal-oxide based transducers.     

Evaluation of a high-affinity QCM immunosensor using antibody fragmentation and 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer

This study evaluated construction of a highly affinitive quartz crystal microbalance (QCM) immunosensor using anti-C-reactive protein (CRP) antibody and its fragments for CRP detection. Three types of antibody were immobilized on the surface of a QCM via covalent-bounding. Then affinity was evaluated through antigen-antibody binding between CRP and its antibody. Affinity between antigen-antibody was shown to be highest when anti-CRP F(ab')2-IgG antibody (70 microg/mL) was immobilized on the QCM. In case of anti-CRP F(ab')2-IgG antibody, affinity which was attributable to antigen-antibody binding was almost twice that of anti-CRP IgG antibody, which is used conventionally for QCM immunosensors. In addition, when it was treated with 2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate, so-called MPC polymer, highly affinitive and selective immunosensing for CRP was achieved without non-specific binding from plasma proteins in human serum. When anti-CRP F(ab')2-IgG antibody was immobilized on the QCM, the detection limit and the linearity of CRP calibration curve were achieved at concentrations from 0.001 to 100 microg/dL even during investigation in serum samples. Experimental results verified the successful construction of a highly affinitive and selective QCM-immunosensor which was modified with anti-CRP F(ab')2-IgG antibody and MPC polymer.     

Efficient and gentle elution of antibodies from an immobilized polypeptide antigen BT saturated magnesium chloride

Summary A model antigen, rabbit immunoglobulin G, was immobilized onto polyester cloth by adsorption. The antigen cloth was reacted with sheep anti-rabbit IgG antibody. Antibody bound to the antigen cloth was nearly quantitatively eluted by saturated MgCl₂, whereas a commercial antibody eluent slowly eluted only about 70 % of the antibody. Exposure of antibody to saturated MgCl₂ for 30 min resulted in no loss of immunoactivity. Saturated MgCl₂, therefore, is an ideal eluent in immunoaffinity purification of antibodies.     

Use of immobilized light-harvesting chlorophyll a/b protein to study the stoichiometry of its self-association.

D. J. Davis & E. L. Gross (1976) Biochim. Biophys. Acta 449, 554-564 previously observed that the light-harvesting chlorophyll a/b protein or chlorophyll protein complex II self-associated as determined by ultracentrifugation. We have determined the stoichiometry of complex formation by immobilizing the monomer on ethylenediamine-Sepharose 4B and determing the ability of immobilized protein to bind the free protein. The amount of soluble protein bound to the immobilized protein increased as the concentration of soluble protein increased. The binding was maximal between pH 7 and 8. The maximum binding was three molecules bound per one molecule of protein immobilized. These results indicate that a tetramer is the intrinsic structural unit of the light-harvesting chlorophyll a/b protein in the chloroplast membrane. Upon complex formation, the chlorophyll fluorescence was decreased without any spectral change. The maximum binding was approximately doubled upon addition of 0.5 mM CaCl2 whereas 5 mM NaCl had no effect. Addition of CaCl2 had no effect on the fluorescence of the monomer. The light-harvesting chlorophyll a/b protein can be isolated from a sodium lauryl sulfate extract of chloroplasts by affinity chromatography using the immobilized light-harvesting chlorophyll a/b protein.     

Binding of Clostridium botulinum type C neurotoxin to rat brain synaptosomes

The binding of Clostridium botulinum type C neurotoxin to rat brain synaptosomes was determined by the use of 125I-neurotoxin. The binding was independent of the incubation temperature (0 degrees C and 37 degrees C) and was equilibrated in 10 min. The dose dependent of 125I-toxin binding to synaptosomes at 0 degrees C showed that there were two kinds of toxin receptors on the synaptosomal membrane; the association constants and maximum binding values were 1.05 x 10(10 M-1, 5.25 x 10(-13) mol/mg of synaptosomal protein and 5.00 x 10(6) M-1, 5.00 x 10(-12) mol/mg of synaptosomal protein, respectively. When the incubation of toxin with synaptosomes was continued at 37 degrees C after 125I-toxin had been pre-incubated with synaptosomes at 0 degrees C for 10 min, the displacement of labeled toxin by the addition of excess amounts of unlabeled toxin decreased slightly with increasing incubation time, and finally 0.4% of the bound 125I-toxin was not displaced from synaptosomes. The binding of 125I-toxin to synaptosomes was inhibited by anti-heavy chain IgG and a monoclonal antibody which neutralized toxin and recognized heavy chain. These results suggest that the binding sites of toxin to synaptosomes are localized on heavy chain and a small amount of the bound toxin is incorporated into the synaptosomal membrane or synaptosomes.     

An ISFET-based immunosensor for the detection of beta-Bungarotoxin

An ion-sensitive field effect transistor (ISFET)-based immunosensor was developed to detect/quantitate beta-Bungarotoxin (beta-BuTx), a potent presynaptic neurotoxin from the venom of Bungarus multicinctus. A murine monoclonal antibody (mAb 15) specific to beta-BuTx was immobilized onto silicon nitride wafers after silanization and activation with glutaraldehyde. A chip based enzyme linked-immunosorbantassay (ELISA) was performed to ascertain antigen binding to the immobilized antibody. To develop an electrochemical immunosensing system for the detection/quantitation of beta-BuTx, an ISFET was used as a solid phase detector. MAb 15 was immobilized on the gate region of the ISFET. The antigen antibody reaction was monitored by the addition of urease conjugated rabbit anti-beta-BuTx antibodies. The sensor can detect toxin level as low as 15.6 ng/ml. The efficacy of the sensor for the determination of beta-BuTx from B. multicinctus venom was demonstrated in mouse model. Toxin concentration was highest at the site of injection (748.0+/-26 ng/ml) and moderate amount was found in the plasma (158.5+/-13 ng/ml).