Affinity purification of immunoglobulins from chicken egg yolk using a new synthetic ligand

Due to the peculiar composition of the egg yolk and the lack of specific affinity ligands, Y immunoglobulins are normally purified using complex and time consuming procedures involving a combination of precipitation and chromatographic steps first to extract and capture and then to polish IgY. In this study, we have examined the applicability for IgY affinity purification of TG19318, a synthetic ligand for immunoglobulin, obtained from the screening of combinatorial libraries, and already characterized for its capability to purify immunoglobulins of class G, M, E and A. Soluble proteins were separated from the lipidic fraction of egg yolk by the water dilution method and loaded on to TG19318 affinity columns prepared by immobilizing the ligand on the commercially available support Emphaze™. In a single chromatographic step TG19318 affinity columns led to an efficient capture of IgY directly from crude samples, and with a purity degree higher than 90%, as determined by densitometric scanning of SDS–PAGE analysis of bound fractions, and with full recovery of antibody activity, as determined by ELISA assay. Higher recovery and purity of IgY was obtained by using loading buffers at pH close to 6.5. Column capacity, determined by applying 4× excess IgY to 1 ml bed volume column, and eluting the retained immunoglobulins, was close to 65 mg of IgY per ml of resin. Chemical and chromatographic stability of TG19318/Emphaze was tested before and after various treatments. The derivatized matrix was found to be very stable, in terms of ligand leakage and maintenance of IgY binding capacity, under conditions of normal column usage, cleaning and storage.     

Biomimetic affinity purification of Candida antarctica lipase B

Candida antarctica lipase B (CalB) is one of the most widely used biocatalysts in organic synthesis. The traditional method for purification of CalB is a multi-step, high cost and low recovery procedure. Biomimetic affinity purification had high efficiency purification. We selected 298 ligand columns from a 700-member library of synthetic ligands to screen Pichia pastoris protein extract. Of the 298, three columns (named as A9-14, A9-10, and A11-33) had one-step purification effect, and A9-14 of these affinity ligands, had both high purification and recovery. The one-step recovery of CalB reached 73% and the purification reached 91% upon purification. The active groups of A9-14 were cyclohexylamine and propenylamine. Furthermore, both A9-14 and A9-10 had the same R1 active group of cyclohexylamine which might act the main binding role for CalB. The synthetic ligand A9-14 had a binding capacity of 0.4 mg/mL and had no negative effects on its hydrolytic activity. Unlike a natural affinity ligand, this synthetic ligand is highly stable to resist 1M NaOH, and thus has great potential for industrial scale production of CalB.     

IgY‐binding peptide screened from a random peptide library as a ligand for IgY purification

Chicken egg yolk immunoglobulin (IgY) is a functional substitute for mammalian IgG for antigen detection. Traditional IgY purification methods involve multi‐step procedures resulting in low purity and recovery of IgY. In this study, we developed a simple IgY purification system using IgY‐specific peptides identified by T7 phage display technology. From disulfide‐constrained random peptide libraries constructed on a T7 phage, we identified three specific binding clones (Y4‐4, Y5‐14, and Y5‐55) through repeated biopanning. The synthetic peptides showed high binding specificity to IgY‐Fc and moderate affinity for IgY‐Fc (K_d: Y4‐4 = 7.3 ± 0.2 μM and Y5‐55 = 4.4 ± 0.1 μM) by surface plasmon resonance analysis. To evaluate the ability to purify IgY, we performed immunoprecipitation and affinity high‐performance liquid chromatography using IgY‐binding peptides; the result indicated that these peptides can be used as affinity ligands for IgY purification. We then used a peptide‐conjugated column to purify IgY from egg yolks pre‐treated using an optimized delipidation technique. Here, we report the construction of a cost‐effective, one‐step IgY purification system, with high purity and recovery. © 2017 The Authors. Journal of Peptide Science published by European Peptide Society and John Wiley & Sons Ltd.     

Biomimetic affinity purification of cardiotoxin and its pharmacological effects on the nervous system

Cobra venom is a very precious natural resource. The traditional method for purification of cardiotoxin from cobra venom is a multi-step, high cost, and low recovery procedure. By molecular modeling and docking with SYBYL software, we designed and synthesized an affinity ligand, m-aminobenzoic acid, for high efficiency purification of this therapeutically useful Chinese cobra venom cardiotoxin. The one-step recovery of cardiotoxin reached 64% and the purity reached 92% upon purification. The binding capacity of this synthetic ligand was 9.1 mg cardiotoxin/g moist weight gel and the affinity constant for cardiotoxin was 5.5 x 10(3) M(-1). Unlike a natural affinity ligand, this synthetic ligand is highly stable, and has great potential for industrial scale production of cardiotoxin. In addition, we examined the effects of cardiotoxin on the nervous system in a mouse model. Results showed that cardiotoxin could maintain analgesic effects for 120 min with a dose of less than 0.06 mg/kg (2.8% of the LD(50)). Administration of 0.12 mg/kg cardiotoxin could improve scopolamine impairments of memory in mice. These results suggest that cardiotoxin may be a potential drug for nervous system diseases.     

The purification of IgY from chicken egg yolk by preparative electrophoresis

Chicken IgY has been purified from egg yolk by preparative electrophoresis on the Gradiflow, a system which has been employed for the purification of a wide range of proteins with high recovery and biological activity. Protein purification on the Gradiflow utilises electrophoresis with selected combinations of porous membranes and buffers. The purification of IgY was achieved by initial PEG lipid precipitation, then a single step Gradiflow run by a strategy based on the relatively high pI range of IgY compared to other egg yolk proteins. The IgY yields obtained from the delipidised supernatant are consistently greater than 80% by immunoassay. The purity of the IgY fraction compared favourably with IgY prepared using three commercial products.     

抗甲型流感鸡卵黄抗体的制备及效价测定

目的:研究抗甲型流感卵黄抗体的制备与纯化,并探讨其效价随免疫时间的变化关系。方法:用灭活甲型流感病毒复合抗原免疫蛋鸡,用PEG6000对卵黄抗体进行分离提取,SDS-PAGE法对其进行分子量测定,考马斯亮蓝法对其含量和纯度进行测定,用微量凝集法检测蛋鸡血清抗体和卵黄抗体的效价。结果:提取得到的卵黄抗体重链分子量为66 kDa、轻链分子量分26 kDa,每毫升卵黄液可得到纯度为95.80%的卵黄抗体9.98mg,回收率93.01%;高效价持续时间90 d以上;免疫蛋鸡血清和卵黄中3种特异性抗体的消长规律基本相似,但抗体水平之间存在明显的差异。结论:采用灭活甲型流感病毒复合抗原免疫蛋鸡可制备高效价、高纯度抗甲型流感卵黄抗体,为卵黄抗体在甲型流感防治中的应用研究奠定了基础。     

抗生殖器疱疹病毒卵黄免疫球蛋白(IgY)的研究

检测了鸡卵黄中抗生殖器疱疹病毒(HSV-2)抗体的产量、纯度、来源及稳定性。采用生殖器疱疹病毒(HSV-2)作为抗原免疫广州黄村鸡。通过改良水稀释法提取卵黄中的IgY。双紫外光波长测定抗体含量,SDS-PAGE电泳检测抗体纯度。Western blot免疫印迹法测定该抗体来源。ELISA检测IgY对温度、酸碱度的稳定性。结果,蛋黄液中抗体质量浓度13.6g.L-1,抗体纯度达96.2%。免疫印迹证明IgY与鸡血清中的IgG具有相同的分子量和抗原性。IgY具有良好的热稳定性,对酸碱具有一定的耐受力。WD水稀释法能得到高产量、高纯度的特异性IgY,而且有良好的生物学活性。     

A novel and efficient immunoglobulin Y extraction method using poloxamer-polyethylene glycol

Although many IgY extraction methods (such as polyethylene glycol (PEG) precipitation method, octanoic acid method, water dilution method, etc.) have been established, there is still industrial drive and real need in developing scale-up IgY production methods. Some previous studies have reported that poloxamer degreasing method shows very good result in IgY extraction from egg yolk with high degreasing speed, harmlessness, simpleness in operation and minimal effect on antibody titer. In this study, we developed a new method, poloxamer-PEG method, to obtain functional IgY with high purity and yield. First, the delipidation solution was added into the diluted yolk samples, and then the filtrates were collected from the diluted yolk samples after 3?hr in room temperature. PEG-6000 was added into the collected filtrates and the mixture was centrifuged after shaking on the roller mixer for 45?min at room temperature. Last, the precipitates were resuspended in 1?mL phosphate buffered solution (PBS) buffer and dialyzed overnight. The results showed that the total protein concentrate of extractive could reach at 30?mg/mL and the purity of the IgY could reach at 92.71% with the novel method, which was superior to the PEG precipitation method and water dilution method.     

Utilizing a library of synthetic affinity ligands for the enrichment, depletion and one-step purification of leech proteins

Although the concept of affinity purification using synthetic ligands had been utilized for many years, there are few articles related to this research area, and they focus only on the affinity purification of specific protein by a defined library of synthetic ligands. This study presents the design and construction of a 700-member library of synthetic ligands in detail. We selected 297 ligand columns from a 700-member library of synthetic ligands to screen leech protein extract. Of the 297, 154 columns had an enrichment effect, 83 columns had a depletion effect, 36 columns had a one-step purification effect, and 58 columns had a one-step purification via flowthrough effect. The experimental results achieved by this large library of affinity ligands provide solid convincing data for the theory that affinity chromatography could be used for the enrichment of proteins that are present in low abundance, the depletion of high abundance proteins, and one-step purification of special proteins.     

抗流感病毒特异性IgY对小鼠的保护作用研究

通过免疫鸡制备抗流感病毒特异性IgY,经纯化后,采用滴鼻途径给小鼠,使小鼠获得被动免疫。结果表明,抗流感病毒特异性IgY可使小鼠对同型的流感病毒的攻击产生保护作用。     

A synthetic ligand for IgA affinity purification

We reported previously that TG19318, a synthetic ligand deduced from the screening of combinatorial libraries, displays specific and selective recognition properties for immunoglobulins of the G class and can be used conveniently for affinity chromatography purification of monoclonal and polyclonal antibodies. In this study we have extended the ligand characterization, examining its ability to bind IgA from cell culture supernatants and from IgG-deprived serum. Affinity columns prepared by immobilizing TG19318 on Sepharose allowed convenient one-step purification of monoclonal IgA directly from crude feedstocks, in high yield and with full recovery of immunoreactivity. Optimal column adsorption occurred with phosphate buffer at neutral pH, while elution of adsorbed IgA could be accomplished by a buffer pH change to acidic or basic conditions. Column capacity was close to 7 mg IgA/ml support.     

Purification of animal immunoglobulin G (IgG) using peptoid affinity ligands

The availability of highly pure animal antibodies is critical in the production of diagnostic tools and biosensors. The peptoid PL16, previously isolated from an ensemble of peptoid variants of the IgG-binding peptide HWRGWV, was utilized in this work as affinity ligand on WorkBeads resin for the purification of immunoglobulin G (IgG) from a variety of mammalian sources and chicken immunoglobulin Y (IgY). The chromatographic protocol initially optimized for murine serum and ascites was subsequently employed for processing rabbit, goat and sheep, donkey, llama, and chicken sera. The PL16-WorkBeads resin proved able to recover all antibody targets with values of yield between 50 and 90%, and purity consistently above 90%. Notably, PL16 not only binds a broader spectrum of animal immunoglobulins than the reference ligands Protein A and G, but it also binds equally well with all their subclasses. Unlike the protein ligands, in fact, PL16 afforded excellent values of yield and purity of mammalian polyclonal IgG, namely murine (47 and 94%), rabbit (66.5 and 91.7%), caprine IgG (63 and 91–95%), donkey, and llama (93 and 97%), as well as chicken IgY (42 and 92%). Of notice, it is also the ability of PL16 to target monomeric IgG without binding aggregated IgG; when challenged with a mixture of monomeric and aggregated murine IgG, PL16 eluted <3% of fed aggregates, against 11–13% eluted by Protein A and G. Collectively, these results prove the potential of the proposed peptoid ligand for large-scale purification of animal immunoglobulins.     

Immunoglobulin specificity of TG19318: a novel synthetic ligand for antibody affinity purification

A synthetic ligand [TG19318], able to mimic protein A in the recognition of the immunoglobulin Fc portion, has been previously identified in our laboratory through the synthesis and screening of multimeric combinatorial peptide libraries. In this study we have fully characterized its applicability in affinity chromatography for the downstream processing of antibodies, examining the specificity and selectivity for polyclonal and monoclonal immunoglobulins derived from different sources. Ligand specificity was broader than protein A, since IgG deriving from human, cow, horse, pig, mouse, rat, rabbit, goat and sheep sera, IgY obtained from egg yolk, and IgM, IgA and IgE were efficiently purified on TG19318 affinity columns. Adsorbed antibodies were conveniently eluted by a buffer change to 0.1 M acetic acid or 0.1 M sodium bicarbonate pH 9, with full retention of immunological properties. Monoclonal antibodies deriving from cell culture supernatants or ascitic fluids were also conveniently purified on TG19318 affinity columns, even from very diluted samples. The affinity constant for the TG19318-IgG interaction was 0.3 microM, as determined by optical biosensor measurements. Under optimized conditions, antibody purity after affinity purification was close to 95%, as determined by densitometric scanning of SDS-PAGE gels of purified fractions, and maximal column capacity reached 25 mg Ig/ml support. In vivo toxicity studies in mice indicated a ligand oral toxicity greater than 2000 mg kg-1 while intravenous toxicity was close to 150 mg kg-1. Validation of antibody affinity purification processes for therapeutic use, a very complex, laborious and costly procedure, is going to be simplified by the use of TG19318, which could reduce considerably the presence of biological contaminants in the purified preparation, a very recurrent problem when using recombinant or extractive biomolecules as affinity ligands.     

Separation and purification of Toxoplasma gondii tachyzoites from in vitro and in vivo culture systems

In this study, we evaluated four methods to separate and purify Toxoplasma gondii tachyzoites from in vivo and in vitro culture systems, including trypsin digestion, purification with a 3-μm filter, CF-11 cellulose purification, and Percoll purification. Our results indicate that both purification with a 3-μm filter and CF11 cellulose purification methods remove leukocytes or HeLa cells, and can therefore be used as candidate methods for the purification of in vivo and in vitro culture products. Trypsin digestion had a high tachyzoite recovery rate, but 22.35% of leukocytes and 69.64% of HeLa cells remained in the purified products. Percoll solution [30% (v/v)] also had a high tachyzoite recovery rate, but 3.44% of leukocytes and 61.61% of HeLa cells remained in the purified products. The 40% Percoll solution was also a candidate method for purifying tachyzoites from in vivo culture products, with a 65.45% tachyzoite recovery rate and without leukocytes.     

Affinity precipitation and macroaffinity ligand facilitated three-phase partitioning for refolding and simultaneous purification of urea-denatured pectinase

Protein refolding is an integral step in the recovery of protein activity from inclusion bodies. It is shown that affinity precipitation and macroaffinity ligand facilitated three-phase partitioning (MLFTPP) led to refolding of urea-denatured pectinase present in a commercial preparation, with simultaneous purification. Affinity precipitation consists of precipitation of the desired enzyme by complexing it with a suitable stimulus-sensitive macroaffinity ligand. This ligand in this case was alginate/esterified alginate. The complex of the polymer-pectinase could be precipitated by adding calcium ions. In MLFTPP (carried out by adding tertiary butanol and ammonium sulfate to the aqueous solution of crude enzyme and the polymer), the polymer or its complex with the enzyme form an interfacial precipitate between tert-butyl alcohol phase and aqueous phase. It is believed that in both processes, while molecular recognition of alginate/esterified alginate to pectinase facilitates their selective binding to the enzyme, the correct refolding is facilitated by preventing molecular aggregation of unfolded enzyme molecules. Three-phase partitioning with esterified alginate as the macroaffinity ligand gave 100% recovery with 4-fold purification. Affinity precipitation with 1% alginate gave 52% yield with 18-fold purification. On the other hand, use of 0.5% esterified alginate gave only 7-fold purification but with 75% recovery of activity.     

Purification of Human α2-Antiplasmin with Chicken IgY Specific to Its Carboxy-Terminal Peptide

ABSTRACT

α₂-antiplasmin, a plasma glycoprotein of the serpin superfamily, is the primary physiological inhibitor of plasmin, the key enzyme in fibrin degradation. Previous purification methods utilize lengthy multistep protocols with low yields or use monoclonal antibodies that are expensive or difficult to make. With a relatively small investment, a chicken was immunized with keyhole limpet hemocyanin-conjugated to α₂-antiplasmin C-terminal 26 residue synthetic peptide and the peptide-specific antibody (IgY) was isolated from the egg yolks of hens using the peptide affinity column. Based on the interaction between this IgY and α₂-antiplasmin, pure α₂-antiplasmin was isolated from human plasma in two steps: (a) citrated plasma was precipitated with 15% PEG-8000 to remove the bulk of plasma proteins while retaining the majority of α₂-antiplasmin activity; and (b) the α₂-antiplasmin was affinity-purified from the supernatant using the IgY column. Yields were typically 48% and the purity and authenticity of the α₂-antiplasmin were verified by gel electrophoresis, Western Blot analysis, N-terminal sequence, and amino acid analysis.     

Efficient stable isotope labeling and purification of vitamin D receptor from inclusion bodies

Vitamin D receptor (VDR) plays a crucial role in many cellular processes including calcium and phosphate homeostasis. Previous purification methods from prokaryotic and eukaryotic expression systems were challenged by low protein solubility accompanied by multi purification steps resulting in poor protein recovery. The full-length VDR and its ligand binding domain (LBD) were mostly (>90%) insoluble even when expressed at low temperatures in the bacterial system. We describe a one-step procedure that results in the purification of rat VDR and LBD proteins in high-yield from Escherichia coli inclusion bodies. The heterologously expressed protein constructs retained full function as demonstrated by ligand binding and DNA binding assays. Furthermore, we describe an efficient strategy for labeling these proteins with (2)H, (13)C, and (15)N for structural and functional studies by nuclear magnetic resonance (NMR) spectroscopy. This efficient production system will facilitate future studies on the mechanism of vitamin D action including characterization of the large number of synthetic vitamin D analogs that have been developed.     

Generation and application of chicken egg-yolk antibodies

Despite the fact that the use of chicken as immunization host brings many advantages to the production of polyclonal antibodies, the generation of egg yolk immunoglobulins (IgY) is rarely chosen. In this review, we report on the fast and efficient method for generation and affinity purification of IgY, in this case raised against the alpha-subunit of hypoxia-inducible factor-1 (HIF-1). The IgY antibody was successfully applied in a variety of methods and a number of different species for HIF-1alpha detection. In electrophoretic mobility shift assays, the IgY antibody recognized the native HIF-1 complex. The IgY antibody also detected HIF-1alpha protein on Western blots with extracts derived from human, monkey, pig, dog and mouse cell lines grown under hypoxic conditions. Immunofluorescence and immunoprecipitation experiments using the IgY antibody allowed detection and subcellular localization of HIF-1alpha in the nuclei of hypoxic cells. Chicken antibody production brings great benefit concerning the welfare of the immunized animals, due to non-invasive antibody harvesting with the added convenience of simple egg collection. An additional advantage is the fast and simple IgY isolation from egg yolk. IgY technology is a great improvement and should be considered as a good alternative to conventional polyclonal antibody production in mammals.     

Affinity chromatographic purification of human immunoglobulin M from human B lymphocyte cell culture supernatant

Compared to immunoglobulin G purification with extensively studied affinity ligands such as protein A and protein G, little work has been done on affinity chromatographic purification of immunoglobulin M. Hexamer peptide ligand HWRGWV, previously shown to bind specifically to the Fc fragment of IgG, also demonstrated potential for IgM purification. This study presents further characterization and investigation of this ligand for its potential for purification of IgM. Different running conditions were employed in order to improve the recovery and purity of IgM. The final recovery and purity of the antibody is feedstock dependent, but can reach levels of both recovery and purity as high as 95%. The dependence of the recovery and purity on total loading amount and initial IgM concentration were investigated and discussed. Although relatively low dynamic binding capacities (DBC) in the range of 4.6–13.1 mg IgM/mL resin at linear flow rates from 173 to 35 cm/h were obtained for IgM compared to IgG because of the large molecular weight of IgM, the DBC value of HWRGWV for IgM is much greater than protein-based IgM affinity ligands found in the literature and is competitive with current commercially available affinity ligands, such as KAPTIVE-M, CaptureSelect IgM and Ultralink Immobilized Mannan Binding Protein.     

Acid stability of anti-Helicobacter pyroli IgY in aqueous polyol solution

IgY was separated from a hen's egg yolk that was immunized with Helicobacter pyroli. The anti-H. pyroli IgY activity at acidic pH and the suppressive effect of polyol on acid-induced inactivation of IgY were investigated. Sorbitol and xylitol were used as polyols. IgY was quite stable at pH 5-7. Irreversible inactivation of IgY was observed at pH below 4, and proceeded rapidly at pH below 3. The acid stability of IgY was enhanced in the presence of 30% sorbitol or above. In a 50% aqueous sorbitol solution, an acid-induced inactivation was almost completely suppressed at pH 3. However, the improvement of IgY activity was not observed in the aqueous xylitol solution. IgY showed almost the same activity as native IgY when sucrose was substituted for sorbitol. On the other hand, the xylitol replacement with sucrose did not enhance the acid stability of IgY. The acid-induced inactivation of IgY was related to tryptophyl fluorescence. Fluorescence emission spectra suggested that structural changes near the tryptophan residues may occur under acidic conditions. An increase in sorbitol concentration induced a blue shift. The fluorescence emission of IgY in a 50% sorbitol solution had a peak at 330 nm, which was the same emission peak that was exhibited by native IgY. Sorbitol could, therefore, be used as a good stabilizer of IgY under acidic conditions.