CN110736796A

CN110736796A - method for detecting molecular weight of pneumococcal capsular polysaccharide

Info

Publication number: CN110736796A
Application number: CN201911008923.0A
Authority: CN
Inventors: 马可; 朱卫华; 宗向坤; 张; 赵林飞; 胡月凤; 杜琳
Original assignee: Anhui Zhifei Longcom Biopharmaceutical Co Ltd; Chongqing Zhi Fei Biological Products Ltd By Share Ltd; Beijing Zhifei Lvzhu Biopharmaceutical Co Ltd
Current assignee: Anhui Zhifei Longcom Biopharmaceutical Co Ltd; Chongqing Zhi Fei Biological Products Ltd By Share Ltd; Beijing Zhifei Lvzhu Biopharmaceutical Co Ltd
Priority date: 2019-10-23
Filing date: 2019-10-23
Publication date: 2020-01-31
Anticipated expiration: 2039-10-23
Also published as: CN110736796B

Abstract

The invention discloses a method for detecting the molecular weight of streptococcus pneumoniae capsular polysaccharide (PnPs) by an HPSEC-RI method, which comprises the steps of preparing a mobile phase, accurately weighing the PnPs, adding the mobile phase for dissolving, diluting with the mobile phase, detecting the viscosity of the PnPs to ensure that the viscosity value of the diluted sample is in a fixed range of , filtering to obtain a sample solution, selecting a plurality of glucan standard products with different molecular weights, diluting with the mobile phase respectively, injecting samples, analyzing by liquid chromatography, establishing a molecular weight standard curve and a regression equation, detecting and recording the sample under the same test condition, and calculating the molecular weight of the sample by using the established standard curve and the regression equation.

Description

method for detecting molecular weight of pneumococcal capsular polysaccharide

Technical Field

The invention belongs to the technical field of biology, and particularly relates to methods for detecting the molecular weight of pneumococcal capsular polysaccharide.

Background

Currently, the vaccines marketed to prevent streptococcus pneumoniae infection are the 23-valent pneumococcal polysaccharide vaccine and the 7-valent/13-valent pneumococcal polysaccharide conjugate vaccine. Pneumococcal capsular polysaccharide (PnPs) is a main effective component of the vaccine, and researches show that the molecular weight of the PnPs directly influences the immunogenicity effect of the polysaccharide vaccine; in combination vaccines, PnPs are also important indexes for quality control as intermediate products of the vaccines.

As for 1 month in 2019, families of 23-valent pneumococcal polysaccharide vaccines are on the market in China, and a plurality of vaccine manufacturers are developing pneumococcal polysaccharide vaccines and pneumococcal polysaccharide conjugate vaccines, but the three parts (2015 edition) of Chinese pharmacopoeia does not include the manufacturing and detection rules of the 23-valent pneumococcal polysaccharide vaccine, and the detection rules of the vaccines recorded in European pharmacopoeia 7.0 edition use gel exclusion chromatography (SEC) to determine the distribution coefficients (K) of various PnPPs samples in chromatographic columns_D) And K is specified for each monovalent polysaccharide_DThe method has the defects of time consumption, labor consumption, poor repeatability and the like. In the aspect of molecular weight determination, as the high performance liquid chromatography technology is mature, a polysaccharide molecular weight standard substance with similar properties to a sample to be measured is detected by a high performance gel exclusion chromatography-differential refraction method (HPSEC-RI), a mass distribution curve of the molecular weight of the standard substance along with the change of the elution time or the volume of the sample is drawn according to the polysaccharide molecular weight standard substance, the corresponding elution index of the sample to be measured is recorded, and the molecular weight of the sample to be measured is measured and calculated through the mass distribution curve.

A large number of experiments prove that when the HPSEC-RI method is used for detecting PnPs, the lower the dilution concentration of some serotype PnPs is, the larger the detection molecular weight result is, and the detection result does not change along with the concentration until the concentration is diluted to fixed concentration, however, the concentration and the viscosity of the PnPs have a positive correlation, the correlation between the viscosity and the molecular weight of all PnPs is counted, and the obtained molecular weight result when the viscosity value of the solution is between 1.0 and 1.3cp tends to be the same .

Disclosure of Invention

The invention aims to provide methods for detecting the molecular weight of pneumococcal capsular polysaccharide.

The molecular weight of the treated sample is detected by a method for detecting the streptococcus pneumoniae capsular polysaccharide (PnPs) by a HPSEC-RI method, so that the molecular weight is more accurate.

The detection method comprises the following steps:

(1) preparing 0.1mol/L phosphate buffer solution as a mobile phase;

(2) accurately weighing PnPs, adding the PnPs into a mobile phase, dissolving, diluting with the mobile phase, and filtering to obtain a sample solution;

(3) selecting a plurality of glucan standard substances with different molecular weights, diluting the glucan standard substances to 1mg/ml by using a mobile phase, injecting a sample, analyzing by using liquid chromatography, and establishing a molecular weight standard curve and a regression equation;

(4) detecting and recording the sample under the same test condition, and calculating the molecular weight of the sample by using the established standard curve and regression equation.

Wherein the mobile phase is phosphate buffer solution, and the formula comprises 0.4g of sodium dihydrogen phosphate dodecahydrate, 6.0g of disodium hydrogen phosphate dihydrate and 9.0g of sodium chloride, and is prepared by adding deionized water to 1000 g.

Wherein, the chromatographic column used for the liquid chromatographic analysis is a silica gel chromatographic column, the chromatographic column is an analytical column of TSK G5000PWXL (7.8mm ID multiplied by 30cm) manufactured by TOSOH corporation of Japan, and the detection conditions of HPSEC-RI are as follows: the monitor temperature is 30 deg.C, the flow rate is 0.5ml/min, the molecular weight standard is prepared into 1mg/ml solution with mobile phase, 100 μ l of each solution is injected.

Wherein, the different viscosities of different serological type PnPs are diluted to 1mg/ml-0.02mg/ml by a mobile phase, the viscosity value of the solution is between 1.0 cp and 1.3cp, and the molecular weight is detected by high performance gel exclusion chromatography-differential refraction method (HPSEC-RI).

Among these, the method is applicable to all streptococcus pneumoniae PnPs.

Wherein, the streptococcus pneumoniae serotypes are PnPs with relatively small viscosity such as

types

1, 2, 4, 5, 6A, 6B, 7F, 8, 9N, 9V, 12F, 10A, 11A, 12F, 14, 15B, 17F, 18C, 19A, 19F, 20, 22F, 23F and 33F, and the viscosity is measured and should be between 1.0 and 1.3 cp.

Wherein, the streptococcus pneumoniae serotype 3 PnPs are diluted to 0.05 mg/ml-0.2 mg/ml, and the viscosity is detected to be between 1.0-1.3 cp.

Preferably, the detection method of the present invention comprises the following steps:

(1) preparing 0.1mol/L phosphate buffer solution as a mobile phase;

(2) accurately weighing PnPs, adding a mobile phase for dissolving for 12-24 hours, diluting with the mobile phase, wherein the concentration of polysaccharide is 0.2mg/ml, the concentration of type 3 polysaccharide is 0.05mg/ml, shaking up, filtering, and detecting the viscosity to be 1.0-1.3CP, namely a sample solution;

(3) selecting a plurality of glucan standard substances with different molecular weights, diluting the glucan standard substances to 1mg/ml by using a mobile phase, injecting a sample, analyzing by using liquid chromatography, and establishing a molecular weight standard curve and a regression equation; the detection conditions of the liquid chromatogram are as follows: the test temperature is 30 ℃, the mobile phase of the system is 0.1mol/L phosphate buffer solution, and the flow rate is 0.5 ml/min;

(1) formulating a mobile phase

0.1mol/L phosphate buffer solution, taking the preparation of 1000ml total solution as an example, the formula is that 0.4g of sodium dihydrogen phosphate dodecahydrate, 6.0g of disodium hydrogen phosphate dihydrate and 9.0g of sodium chloride are weighed, and deionized water is added to reach 1000 g.

(2) Establishing standard curve and regression equation

Preparing the molecular weight standard substance into a solution with the concentration of 0.2mg/ml by using a mobile phase, and respectively preparing the sample to be detected into corresponding concentrations by using the mobile phase, and sampling 100 mu l of the solution.

The HPSEC-RI detection conditions are as follows: the test temperature is 30 ℃, the mobile phase of the system is 0.1mol/L phosphate buffer solution, and the flow rate is 0.5 ml/min.

The peak-tip retention time of series of standard products with known molecular weights is detected by HPSEC-RI, the peak-tip retention time is taken as an abscissa, and a logarithmic value (lgMp) of each standard product is taken as an ordinate to establish a molecular weight distribution standard curve and a regression equation.

(3) Streptococcus pneumoniae capsular polysaccharide dilution

Dissolving PnPs12-24 h to be detected by using the diluent, uniformly mixing, and then diluting the polysaccharide solution by using a mobile phase until the polysaccharide concentration is 0.2mg/ml, and diluting the type 3 by using the mobile phase until the polysaccharide concentration is 0.05 mg/ml. The viscosity is measured by a viscometer, and the viscosity at 25 ℃ is 1.0-1.3 CP.

(4) Molecular weight detection

The HPSEC-RI detection conditions comprise that the test temperature is 30 ℃, the mobile phase of the system is 0.1mol/L phosphate buffer solution, the flow rate is 0.5ml/min, the peak tip retention time of a sample to be detected is detected and recorded under the same test conditions with the standard substance, the lgMp of the sample is calculated by applying the established standard curve and a regression equation, and the corresponding molecular weight is obtained in step .

The detection method of the invention has the beneficial effects that: the conventional HPSEC-RI method does not consider the influence of viscosity factors when detecting PnPs, and has larger errors.

Compared with the existing method, the detection method provided by the invention has the characteristics of high accuracy, good repeatability, good stability and the like.

Drawings

FIG. 1 is a graph of the molecular weight standards of example 1.

Figure 2 is a GPC diagram of serotype 8 PnPs diluted to different concentrations in example 1.

FIG. 3 is a GPC chart of serotype 3 PnPs diluted to different concentrations in Experimental example 1.

Detailed Description

The invention is further illustrated in by the following specific examples, which are not intended to be limiting of the invention.

Materials referred to in the following examples:

streptococcus pneumoniae capsular polysaccharide

Streptococcus pneumoniae

types

1, 2, 3, 4, 5, 6A, 6B, 7F, 8, 9N, 9V, 12F, 10A, 11A, 12F, 14, 15B, 17F, 18C, 19A, 19F, 20, 22F, 23F and 33F for a total of 24 serotypes of PnPs.

Reagent and instrument

Viscometer, electronic balance, high-phase liquid chromatograph, diluent and mobile phase, and dextran standard.

Example 1:

1) instrument and reagent

Model JA2003 electronic balance was purchased from Shunhui scientific instruments, Inc., Shanghai; DV2T type viscometer available from BROOK FIELD Inc., spindle model number CPA-40Z; e2695 high performance liquid system pump, Waters 2414 differential refractometer, available from Waters; high performance liquid chromatography columns were TSK PWXL Guard column and TSK G5000PWXL (7.8 mmID. times.30 cm) analytical column from TOSOH corporation of Japan.

Reagent: sodium dihydrogen phosphate dodecahydrate, disodium hydrogen phosphate dihydrate, sodium chloride, dextran Standards were purchased from Waters Corporation and American Polymer Standards Corporation.

0.1mol/L phosphate buffer solution is prepared by weighing 0.4g of sodium dihydrogen phosphate dodecahydrate, 6.0g of disodium hydrogen phosphate dihydrate and 9.0g of sodium chloride, and adding deionized water to 1000 g.

2) Preparation of type 8 serum PnPs analysis sample

Accurately weighing 50mg of 8-type serum PnPs, adding 10ml of mobile phase to dissolve for 18 hours, and diluting a sample to 2mg/ml, 0.4mg/ml and 0.08mg/ml by using the mobile phase, wherein the specific concentration is shown in Table 1; shaking, filtering, and detecting viscosity to be 1.0-1.3CP to obtain sample solution;

3) detection of serum type PnPs of Streptococcus pneumoniae type 8

Detecting and recording the peak retention time of a sample to be detected, calculating lgMp of the sample by using an established standard curve and a regression equation, and obtaining the viscosity of the PnPs sample with the corresponding molecular weight (Mp) of 2mg/ml to be 1.50CP, wherein the viscosity is beyond the viscosity detection range, the molecular weight (Mp) result is slightly small, the viscosity of the PnPs sample without 0.4mg/ml and 0.08mg/ml is between 1.0 and 1.3CP, the average molecular weight (Mp) of the two results is 1488KD, and a GPC chart of the PnPs type 1.8 shown in a table is shown in a figure 3.

TABLE 1 results of viscosity and Mp values for serotype 19 type A PnPs

Example 2:

1) instrument and reagent

2) Preparation of 33F type serum PnPs analysis sample

Accurately weighing 50mg of 33F type serum PnPs, adding 10ml of mobile phase to dissolve for 16 hours, diluting the sample to 0.2mg/ml by using the mobile phase, and detecting the viscosity to be 1.0-1.3CP to obtain a test solution;

3) detection of Streptococcus pneumoniae type 33F serous PnPs

Detecting and recording the peak retention time of the sample to be detected, calculating the lgMp of the sample by using the established standard curve and regression equation, and obtaining the corresponding molecular weight (Mp) of the sample, continuously detecting for 2 times, averaging the two results, and then obtaining the molecular weight (Mp) of 2766KD, which is shown in Table 2.

TABLE 2 results of viscosity and Mp values of PnPs of serotype 33F

Test example 1: comparative experiment

Compared with the existing method, the detection method provided by the invention has the advantages that the sample loading concentration is fixed when the molecular weight of the PnPs is detected by the existing HPSEC-RI method, the concentrations used in different laboratory detections are not completely the same, but the viscosity of different serotype PnPs is greatly different, the same serotype PnPs and different batches have definite difference, and the viscosity has a great influence on the molecular weight detected by the HPSEC-RI method in the experiment.

This test example simulates the prior HPSEC-RI assay with different loading concentrations of type 3 serum PnPs, and compares it with the results of the invention with increased viscosity control. In the range of 0.25-2.0mg/ml, the viscosity value is 1.45-5.54CP, the difference of the HPSEC-RI method in the detection of the molecular weight Mp value of PnPs is large, and the RSD value is 23.01%; in the range of 0.03125-0.125mg/ml, the viscosity value is in the control range (1.0-1.3CP), the HPSEC-RI method has no obvious difference in the result of detecting the molecular weight Mp value of PnPs, and the RSD value is 1.19%. See table 5. According to the invention, viscosity control is added in the sample dilution process, so that the accuracy of the HPSEC-RI method in detecting PnPs is improved.

1) Instrument and reagent

2) Preparation of type 3 serum PnPs analysis sample

Accurately weighing 50mg of 3-type serum PnPs, adding 10ml of mobile phase to dissolve for 18 hours, diluting a sample from 5mg/ml to 0.03125mg/ml by using the mobile phase, wherein the specific concentration is shown in Table 3; then, the sample is diluted to 0.05mg/ml by using the mobile phase, and 10 parts of the sample are respectively marked as type 3-sample 1 to type 3-sample 10, which is shown in a table 4; shaking, filtering, and detecting viscosity to be 1.0-1.3CP to obtain test solution;

3) detection of streptococcus pneumoniae serotype 3 PnPs

Detecting and recording the peak retention time of the sample to be detected, calculating the lgMp of the sample by using the established standard curve and regression equation, and obtaining the corresponding molecular weight, wherein the difference between different concentrations of the molecular weight (Mp) of the sample is large, the detection Mp is not obviously different when the concentration is reduced to be below 0.125mg/ml, the corresponding viscosity is 1.26CP, and the table 3 shows that the viscosity is high.

4) Precision survey

The results of examining 10 different samples of the same batches of type 3 show that the method detects serotype 3 PnPs with the concentration of 0.05mg/ml, the viscosity of 1.20 to 1.23, the difference of the results of the molecular weight Mp is small, the RSD value is 1.29 percent, and the precision is good, which is shown in Table 4.

TABLE 3 results of viscosity and Mp values for serotype 3 PnPs

TABLE 4 results of measuring viscosity and Mp values of 0.05mg/ml serotype 3 PnPs

Test example 2: screening experiments

The invention has the core point that the viscosity of a detection sample is controlled within range by dilution, so that the detection result is more accurate, the most preferable detection method is obtained by detecting the Mp values of different viscosities of 24 serotype PnPs and screening, the viscosity of the detection sample is controlled within 1.0-1.3CP, and the method has high result accuracy, good repeatability and good stability.

Taking type 1 PnPs, type 3 PnPs and type 19A PnPs as examples, the viscosity of polysaccharide samples of three serotypes is reduced along with the reduction of concentration, the Mp value is increased along with the reduction of viscosity when the viscosity is more than 1.3, and the viscosity is not obviously changed between 1.0 and 1.3 CP. Calculating the precision, the concentration interval of 1 type PnPs viscosity between 1.0 and 1.3 is 0.03125 to 0.5mg/ml, and the RSD value is 1.84 percent; the viscosity of the type 3 PnPs ranges from 1.0 to 1.3, the concentration range is 0.03125 to 0.125mg/ml, and the RSD value is 1.19 percent; the viscosity of the 19A type PnPs ranged from 1.0 to 1.3 at a concentration ranging from 0.03125 to 0.5mg/ml, and the RSD value was 4.85%, as shown in Table 5. Therefore, it is the most preferable method to control the viscosity of the test sample to 1.0 to 1.3.

TABLE 51 type PnPs, 3 type PnPs, and 19A type PnPs viscosity and Mp value results

Claims

The method for detecting the molecular weight of pneumococcal capsular polysaccharide includes the following steps of preparing a mobile phase, accurately weighing PnPs, adding the PnPs into the mobile phase, dissolving, diluting with the mobile phase, filtering to obtain a sample solution, selecting a plurality of glucan standard products with different molecular weights, diluting to 1mg/ml with the mobile phase, injecting samples, analyzing by liquid chromatography, establishing a molecular weight standard curve and a regression equation, detecting and recording the sample under the same test conditions, and calculating the molecular weight of the sample by using the established standard curve and regression equation.
2. The method of claim 1, wherein: the mobile phase is phosphate buffer solution, and taking the total solution amount of 1000ml as an example, the formula is that 0.4g of sodium dihydrogen phosphate dodecahydrate, 6.0g of disodium hydrogen phosphate dihydrate and 9.0g of sodium chloride are weighed, and deionized water is added to reach 1000 g.
3. The method of claim 1, wherein: the chromatographic column used for the liquid chromatographic analysis is a silica gel chromatographic column, the chromatographic column is an analytical column of TSK G5000PWXL (7.8mm ID multiplied by 30cm) manufactured by TOSOH corporation of Japan, and the detection conditions of HPSEC-RI are as follows: the monitor temperature is 30 deg.C, the flow rate is 0.5ml/min, the molecular weight standard is prepared into 1mg/ml solution with mobile phase, 100 μ l of each solution is injected.
4. The method of claim 1, wherein: diluting to 1mg/ml-0.02mg/ml by mobile phase according to different viscosities of different serotype PnPs to make the viscosity value of the solution between 1.0-1.3cp, and detecting the molecular weight by high performance gel exclusion chromatography-differential refraction method (HPSEC-RI).
5. The method of claim 1, wherein: this method is applicable to all streptococcus pneumoniae PnPs.
6. The method of claim 4, wherein: the streptococcus pneumoniae serotypes are 1 type, 2 type, 4 type, 5 type, 6A type, 6B type, 7F type, 8 type, 9N type, 9V type, 12F type, 10A type, 11A type, 12F type, 14 type, 15B type, 17F type, 18C type, 19A type, 19F type, 20 type, 22F type, 23F type and 33F type which are diluted to 0.2 mg/ml-2 mg/ml, and the viscosity is detected to be 1.0-1.3 cp.
7. The method of claim 4, wherein: the streptococcus pneumoniae serotype 3 PnPs are diluted to 0.05 mg/ml-0.2 mg/ml, and the viscosity is detected to be between 1.0-1.3 cp.
8. The method of claim 1, comprising the steps of:

(1) preparing 0.1mol/L phosphate buffer solution as a mobile phase;

(2) accurately weighing PnPs, adding a mobile phase for dissolving for 12-24 hours, diluting with the mobile phase, wherein the concentration of polysaccharide is 0.2mg/ml, the concentration of type 3 polysaccharide is 0.05mg/ml, shaking up, filtering, and detecting the viscosity to be 1.0-1.3CP, namely a sample solution;

(3) selecting a plurality of glucan standard substances with different molecular weights, diluting the glucan standard substances to 1mg/ml by using a mobile phase, injecting a sample, analyzing by using liquid chromatography, and establishing a molecular weight standard curve and a regression equation; the detection conditions of the liquid chromatogram are as follows: the test temperature is 30 ℃, the mobile phase of the system is 0.1mol/L phosphate buffer solution, and the flow rate is 0.5 ml/min;

(4) detecting and recording the sample under the same test condition, and calculating the molecular weight of the sample by using the established standard curve and regression equation.
9. The method of claim 1, comprising the steps of:

(1) formulating a mobile phase

0.1mol/L phosphate buffer solution, taking the preparation of 1000ml total solution as an example, the formula is that 0.4g of sodium dihydrogen phosphate dodecahydrate, 6.0g of disodium hydrogen phosphate dihydrate and 9.0g of sodium chloride are weighed, and deionized water is added to reach 1000 g;

(2) establishing standard curve and regression equation

Preparing the molecular weight standard substance into a solution with the concentration of 0.2mg/ml by using a mobile phase, and respectively preparing the sample to be detected into corresponding concentrations by using the mobile phase, and sampling 100 mu l of the solution;

the HPSEC-RI detection conditions are as follows: the test temperature is 30 ℃, the mobile phase of the system is 0.1mol/L phosphate buffer solution, and the flow rate is 0.5 ml/min;

detecting series of standard products with known molecular weight by HPSEC-RI, establishing a molecular weight distribution standard curve and a regression equation by taking the peak retention time as an abscissa and taking a logarithmic value (lgMp) of each standard product as an ordinate;

(3) streptococcus pneumoniae capsular polysaccharide dilution

Dissolving PnPs12-24 h to be detected by using the diluent, uniformly mixing, and then diluting the polysaccharide solution by using a mobile phase until the polysaccharide concentration is 0.2mg/ml, and diluting the type 3 by using the mobile phase until the polysaccharide concentration is 0.05 mg/ml. Detecting viscosity with viscometer, wherein the viscosity at 25 deg.C should be 1.0-1.3 CP;

(4) molecular weight detection

The HPSEC-RI detection conditions comprise that the test temperature is 30 ℃, the mobile phase of the system is 0.1mol/L phosphate buffer solution, the flow rate is 0.5ml/min, the peak tip retention time of a sample to be detected is detected and recorded under the same test conditions with the standard substance, the lgMp of the sample is calculated by applying the established standard curve and a regression equation, and the corresponding molecular weight is obtained in step .