Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
  • G01N33/68—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving proteins, peptides or amino acids
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
  • G01N33/68—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving proteins, peptides or amino acids
  • G01N33/6803—General methods of protein analysis not limited to specific proteins or families of proteins
  • G01N33/6842—Proteomic analysis of subsets of protein mixtures with reduced complexity, e.g. membrane proteins, phosphoproteins, organelle proteins
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
  • G01N33/68—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving proteins, peptides or amino acids
  • G01N33/6803—General methods of protein analysis not limited to specific proteins or families of proteins

Definitions

• the present invention relates to a method for characterizing the glycosylation of glycoproteins and an in vitro method for determining the bioavailability of glycoproteins which is based on the "hypothetical charge number" (hereinafter referred to as "Z") and both for endogenous Glycoproteins as well as exogenous glycoproteins can be used.
• Z hyper charge number
• exogenous glycoproteins are e.g. recombinant therapeutic glycoproteins derived from mammalian cells (such as interleukin 2, erythropoietin, tissue plasminogen activator or antithrombin III). These substances have aroused considerable interest in scientific, pharmaceutical and official institutions in recent years.
• endogenous glycoproteins are human or non-human (e.g. bovine) serum glycoproteins (such as, for example, human ⁇ -] acidic glycoprotein, human transferrrin or bovine fetuin, but also glycoproteins of other species, such as, for example, B. Chicken Ovomucoid or Pig Thyroglobulin.
• bovine serum glycoproteins such as, for example, human ⁇ -] acidic glycoprotein, human transferrrin or bovine fetuin, but also glycoproteins of other species, such as, for example, B. Chicken Ovomucoid or Pig Thyroglobulin.
• the proportion of sialic acid (N-acetyl-neuraminic acid, Neu ⁇ Ac) has played an important role as a parameter since it is assumed that the presence or absence of Neu ⁇ Ac determines the circulation half-life of a glycoprotein decisively determined in the blood or its clearance.
• Neu ⁇ Ac N-acetyl-neuraminic acid
• EPO still require the very complex, time-consuming, expensive but rather imprecise determination of the therapeutic effectiveness of the glycoprotein in animal experiments (in vivo assay).
• an in vitro assay should be available which is simple and reliable to perform and which also satisfies the legitimately high demands of the regulatory authorities.
• the present invention was therefore based on the technical problem of providing an in vitro method which is suitable for determining the degree of glycosylation of a glycoprotein so easily and reliably that the method is suitable for using the known in vivo methods e.g. to determine bioavailability and batch consistency.
• Z can advantageously also be used in a method for determining the batch consistency.
• the present investigations allow the conclusion that the "glycosylation status" is characterized by Z. Therefore, by determining Z, the glycosylation can be compared in a simple way.
• glycoprotein in connection with the present invention means the composition of the glycan Pools of bi-, tri- and tetraantennary glycans and their respective degree of sialylation (the content of bound N-acetylneuraminic acid) and the content of sulfate or phosphate groups.
• the bioavailability of a glycoprotein therapeutic agent means the ability of the therapeutic agent to develop its biological activity or therapeutic activity in vivo. Accordingly, the bioavailability and the biological activity are largely determined by the in vivo clearance behavior, that is to say the removal of the therapeutic agent from the blood circulation.
• EPO for example, it is known that in the absence of the N-acetylneuraminic acid terminally bound in the N-glycosidic sugar chains, it is removed from the blood circulation very quickly via the so-called "asialo-receptor" in the liver and thus its biological effectiveness cannot unfold.
• the Z of a therapeutic glycoprotein surprisingly correlates with the in vivo half-life of the glycoprotein and thus represents a completely new measurement parameter, which allows the clearance behavior to be expected for the therapeutic glycoprotein from batch to batch in a very simple manner in the to estimate in advance.
• Z also makes it possible to make a statement about the biological safety to be expected for the glycoprotein from batch to batch and its therapeutic effectiveness. Therefore, when determining Z of a therapeutic glycoprotein from batch to batch z. B. dispense with the very complex, time-consuming, expensive and rather imprecise determination of the therapeutic effectiveness of the glycoprotein in animal experiments (in-vivo assay). This also enables a new and significant contribution to the reduction of animal experiments and thus to improved animal protection.
• the Z is a particularly suitable measure of batch consistency.
• endogenous glycoproteins e.g. B. in a human serum glycoprotein, in which the glycosylation varies approximately with a disease
• Z can define as a diagnostic measurement parameter which correlates with the disease and which thus allows a statement about the severity of the disease.
• inflammatory diseases for example for the "acute phase glycoproteins", such as, for. B. ⁇ i -acidic glycoprotein, which is known to change glycosylation with the appearance of inflammation (De Graaf et al. (1993) J. Exp. Med. 177, 657-666).
• tumor diseases in which the content of protein-bound sialic acid (and thus the glycosylation) changes with the progression of the tumor disease (Shahangian et al. (1991) Clin. Chem. 37, 200-204).
• a statement can be made about the stage of the tumor disease, based on the finding that sialylation changes during tumor growth (Shahangian et al., Ibid., S. 200).
• transferrin for the characterization of cerebrospinal fluid, for the diagnosis of secret alcohol abuse and the "carbohydrate deficient glycoprotein syndrome" (De Jong et al., Ibid., Pp. 219-226) and glycoforms of the ⁇ -j-acidic glycoprotein for the diagnosis of inflammation and cancer (Mackiewicz & Mackiewicz, ibid., Pp. 241-247).
• Z can advantageously be used to determine the stage of illness of a patient.
• the distribution of the glycan groups which are uniform in charge is a decisive feature for the bioavailability of a glycoprotein and the batch consistency. It is essential to the invention that the glycan groups which are uniform in charge are weighted in accordance with their charge, in particular their degree of sialysis. These weighted portions are summarized in the Z.
• the Z of a glycoprotein can be determined very well and precisely, e.g. B. by using an optimized and standardized chromatographic method, as it was recently described (Hermentin et al. (1992) Anal. Biochem., 203, 281-289).
• the Z of a glycoprotein is determined by
• glycan pool of glycoprotein in a manner known per se either by chemical means, for. B. (by means of hydrazinolysis) or by enzymatic means (for example by means of PNGase F) released and isolated, b) primarily in a known manner by means of ion exchange chromatography (preferably by means of HPAE-PAD) separated by charge, c ) the percentage areas of the charge-separated peak or glycan groups are determined in a manner known per se, d) the percentage area portions of the peak or glycan groups in neutral (asialo-, as), monosialo- (MS), disialo- (DiS) , trisialo- (TriS), tetrasialo- (TetraS) and pentasialo (PentaS) range with zero (asialo) or 1 (MS) or 2 (DiS) or 3 (TriS) or 4 (TetraS) or 5 (PentaS)
• the Asn-linked sugar chains of the glycoproteins can be released in two ways in a manner known per se - namely either chemically (e.g. by means of hydrazinolysis) or enzymatically (e.g. by means of N- Glycanase or PNGase F).
• the enzymatic process requires reaction conditions to be optimized on a case-by-case basis - for example a tryptic digestion of the glycoprotein to be introduced or the addition of a suitable detergent.
• hydrazinolysis also requires special know-how if one wants to minimize the side reactions. However, today it can be carried out fully automatically using a device from Oxford GlycoSystems (the GlycoPrep 1000).
• the N-glycans are primarily charged. That is, separated according to the number of their sialic acid residues (Hermentin et al. (1992) Anal. Biochem. 203, 281-289), which is why it is particularly suitable for determining the Z of glycoproteins.
• glycoprotein which has predominantly tetra-tennial tetrasialo (C4-4 * ) structures such as. B. recombinant erythropoietin, a Z of about 400.
• C4-4 * tetra-tennial tetrasialo
• a glycoprotein which predominantly has triantennary trisialo (C3-3 * ) structures such as, for. B. bovine fetuin, a Z of about 300
• a glycoprotein which predominantly has biantennary disialo (C2-2 *) structures such as. B. human antithrombin III, a Z of about 200.
• a glycoprotein which, for example, has only asialo structures such as. B. bovine pancreatic ribonuclease B, or so-called "trunkated forms" (trunk structures), such as. B. Chicken Ovomucoid, a Z of approximately 0 is obtained.
• HPAE-PAD high-pH anion-exchange chromatography with pulsed amperometric detection
• This method first separates the N-glycans isolated from the glycoprotein according to their charge and thus enables a statement about the composition of the N-glycan pool from neutral (asialo) as well as mono-, di-, tri- and tetrasialo Structures (that is, N-glycans with zero to four negatively charged neuraminic acid residues).
• the sugar is measured very selectively and sensitively - and without derivatization of the glycans - by pulsed amperometric detection on a gold electrode.
• the glycans were released and isolated from various glycoproteins in a manner known per se either by means of automated hydrazinolysis (using the GlycoPrep 1000 TM, Oxford GlycoSystems, OGS) or by enzymatic means (using PNGase F) or directly by the Oxford GlycoSystems company Purchased as glycan pools and measured using HPAE-PAD in the standard gradient "S" (Hermentin et al. (1992) Anal. Biochem. 203, 281-289).
• N-glycans of a glycoprotein in addition to neuraminic acid e.g. B. also contain sulfate groups
• the determination of the Z z. B. so that the charge-separated peak groups, which are in the chromatogram in the range of 6 or 7 charges, are multiplied by 6 or 7.
• IL-4R CHO
• the glycan pool of the IL-4R sample (batch E4-930914, Behringwerke AG) was analyzed on 3 different days in 6 different batches using automatic hydrazinolysis - in the presence of LNFP-V as internal standard S1 - (GlycoPrep 1000 TM , Oxford GlycoSystems; simultaneous hydrazynolysis on both reactors; batch 1 mg IL-4R per reactor) released and isolated.
• Table 1 shows the respective integrated peak area proportions for each of the 18 HPAE-PAD individual runs and the summation carried out in each case in accordance with equation 1.
• the HPAE-PAD mapping chromatogram from FIG. 1 serves as an illustrative example and reference run.
• the N-glycans were released after reduction of the glycoprotein (500 ⁇ g) using dithioerythrol (DTE; 25 ⁇ l of a 0.3 M aqueous DTE solution) for 10 min at 70 ° C.
• DTE dithioerythrol
• the excess DTE was removed by concentration in a Centricon cartridge with an exclusion limit of 10,000 D (from Amicon), and the concentrate was washed three times with glycanase digestion buffer in the Centricon tube.
• the concentrate was transferred to an Eppendorf cone and in glycanase digestion buffer (500 ⁇ l) a) with and b) without the presence of 0.5% CHAPS using PNGase F (Boehringer Mannheim; 5 units) in 50 mM sodium phosphate buffer , pH 7.6 digested for 48 h at 37 ° C.
• N-glycans were released analogously to Example 2a) or 2a).
• a preparation of soluble murine interleukin-4 receptor (rmur IL-4R, Behringwerke AG) obtained from BHK cells was carried out in a manner known per se via an anion exchange resin (Q-Sepharose, Pharmacia) in 5 fractions. ions Q1-Q5 separated ( Figure 2).
• the analysis of the individual fractions was carried out in a manner known per se.
• the IEF band pattern was scanned in a manner known per se using a gel evaluation software. The band scans obtained are shown in FIG. 3.
• the analytical data obtained in a manner known per se are shown in Table 3.
• N-acetylneuraminic acid (Neu ⁇ Ac; sialic acid) was determined according to Hermentin and Seidat (in: GBF Monographs, Vol 15, pp 185-188, H. S. Conradt, ed., VCH, Weinheim / New York / Cambridge)
• the monosacchrid was determined in a manner known per se according to Hardy et al. (Anal. Biochem. (1988) 170, 54-62). The quotient Neu5Ac / Gal (mol / mol) was determined from the result of the monosaccharide analysis.
• Man / Gal ratio also allows a statement about the expected clearance behavior of a glycoprotein, since glycoproteins with "high mannose” structures also have a receptor in the liver (the so-called “high mannose” receptor) from the blood circulation be removed. Since the content of "high-mannose” structures is included in the calculation of the hypothetical charge number according to equation 1, Z also reflects the content of "high-man structures” and thus also allows a prediction of the clearance via the "high-man” -Receptor".
• the clearance rate of IL-4R was determined as follows:
• the sialic acid content increases continuously from fraction Q1 (13.6 ⁇ g / mg) to fraction Q4 (109.5 ⁇ g / mg), while it turns out to be practically identical in fractions Q4 and Q5 (Table 3).
• the results of the sialic acid determination therefore correlate well with the results of the isoelectric focusing.
• the degree of sialization (Neu ⁇ Ac / Gal; mol / mol) is a less reliable parameter than the Neu ⁇ Ac determination or the isoelectric focusing, because the inaccuracies of the two individual tests (ie the determination of neuraminic acid and monosaccharide component analysis).
• the determination of Z very well reflects both the results of the sialic acid determination and the qualitative course of the isoletric focusing and appears (like the Neu ⁇ Ac determination and the IEF) to determine the degree of sialylation (Neu5Ac / Gal; mol / mol). (The fact that the determination of Z also proves to be superior to the Neu ⁇ Ac determination is shown in Example 6 below).
• the clearance behavior (AUD, area under data; ⁇ g / ml * min) of the fractions Q1-Q ⁇ was also determined in a manner known per se.
• the circulation half-life of the IL-4R in the blood of the mouse is greater the greater the AUD.
• the Z therefore has the particular advantage that Z according to equation 1 both the expected clearance via the asialo receptor and the expected clearance via the high-man receptor are detected and thus enable a more precise prediction of the expected clearance behavior than any other of the analysis methods mentioned.
• IL-4R storage capacity of IL-4R in the fermenter harvesting medium
• aliquots of the harvest were stored at different temperatures (RT, + 4 ° C, -20 ° C and -70 ° C). Aliquots were taken at zero time and after 1, 2 and 3 months.
• the IL-4R was purified from these aliquots in a manner known per se by means of affinity chromatography on an immobilized anti-IL-4R monoclonal antibody.
• the neuraminic acid content and the Z were determined in each case from the purified IL-4R samples. The results are summarized in Figure 4.
• the Z proved to be constant for the samples stored at -70 ° C. and -20 ° C., but fell significantly in the case of the samples stored at + 4 ° C. and massively with increasing storage time in the case of the samples stored at RT from.
• the results of the neuraminic acid determination are of significantly less informative value, although a tendency analogous to the charge number can be seen. It is therefore obvious that the determination of the charge number is analytically superior to the neuraminic acid determination.
• the advantage is based on the high accuracy with which the charge number can be determined - with the particular advantage that - in contrast to the determination of neuraminic acid - the reference to the (glyco) protein concentration is not necessary and thus for the determination of the charge number the inaccuracy of the protein determination is not included in the test result.
• N-glycans were carried out from rhu EPO (BHK) (Merckle AG) using PNGase F in a manner known per se (Nimtz et al., Eur. J. Biochem. (1993) 213, 39- ⁇ 6).
• N-glycans The release of the N-glycans was carried out from rhu EPO (CHO) (Boehringer Mannheim) using PNGase F in a manner known per se (Nimtz et al., Ibid.).
• Example 10 shows that the incomplete extraction of the N-Glycan pool from AGP (when using PNGase F) can be demonstrated by calculating the charge number (analogously to Example 1):
• N-glycans from AGP were isolated after 48 hours of incubation with PNGase F.
• the Z is therefore very advantageously suitable for characterizing the glycosylation status of a glycoprotein.
• Pig thyroglobulin OGS 82 human alpha-1 acid BW AG (Behringwerke AG)
• GlycoPrep glycoprotein 289 human serum transferrin OGS 207 human antithrombin III BW AG GlycoPrep 180 human fibrinogen OGS 184 alpha-1 -T-glycoprotein BW AG
• FIG. 1 shows the N-glycan mapping profile of rhu IL-4R (batch E4-930914) after separation using HPAE-PAD under standard conditions according to Hermentin et al., Anal. Biochem. 203 (1992), pp. 281-289.
• the glycans are located in the chromatogram between S1 and S2.
• the peaks before S1 originate from hydrazinolysis; the peaks after S2 are less known
• FIG. 2 shows the fractionation of rmur IL-4R (lot 018PP) by means of anion exchange chromatography on Q-Sepharose FF.
• FIG. 3 shows the isoelectric focusing (IEF) of the Q-Sepharose fractions of rmur IL-4R lot 018PP obtained according to FIG. 2.
• FIG. 4 a shows the drop in the Z
• FIG. 4 b shows the drop in the NANA content of rhu IL-4R in the culture supernatant when stored at room temperature (RT) + 4 ° C., -20 ° C. and -70 ° C.

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• 1995
  • 1995-07-26 DE DE19527054A patent/DE19527054A1/de not_active Withdrawn
• 1996
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  • 1996-05-30 ES ES96917465T patent/ES2162652T3/es not_active Expired - Lifetime
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  • 1996-05-30 JP JP50713697A patent/JP3631495B2/ja not_active Expired - Fee Related
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