Here we discuss whether N terminal sequencing is appropriate as one of the conventional control methods for monoclonal antibody products. We determined the N terminal sequences of two monoclonal antibody products targeting two antigens separately with both Edman degradation and mass peptide spectrometry. We also identified the characteristic peptide fragments with mass spectrometry. Furthermore, we analyzed their heterogeneity with ion exchange chromatography, capillary zone electrophoresis and Imaged Capillary Isoelectric Focusing. Edman degradation method showed that the N terminal 15 amino acids of heavy and light chains of the two monoclonal antibodies were identical. Peptide mass spectrometry demonstrated that T1 peptide fragments of heavy and light chains of the two antibodies were also the same. But in contrast, peptide mapping and the three analytical methods for heterogeneity analysis could effectively identify and differentiate the two antibodies. The N terminal sequences of two monoclonal antibodies are identical because the number of framework sequences of humanized or human monoclonal antibodies is relatively limited, so whether N terminal sequencing analysis could be regulated as one of the practical control methods should be carefully discussed. Our work also proves that the above analytical methods could combinatorially applied to the identification of monoclonal antibody products, and are more objective compared to N terminal sequencing.
Amino Acid Sequence ; Antibodies, Monoclonal ; isolation & purification ; Chromatography, Ion Exchange ; Humans ; Isoelectric Focusing ; Mass Spectrometry ; Peptide Mapping ; Peptides ; Sequence Analysis, Protein ; methods

Objective The present study investigated the expression of heat shock cognate protein 70 (Hsc70) in the synovial tissues and blood samples of patients with rheumatoid arthritis (RA) to determine the pathological role of this protein in the pathogenesis of the disease.Methods The expression of Hsc70 in synovial membranes was quantitatively analyzed by immunohistochemistry,real-time quantitative PCR and western blotting.The samples from osteoarthritis (OA) and ankylosing spondylitis (AS) were used as controls.The levels of Hsc70 in blood of patients with RA were determined using enzyme linked immunosorbent assay (ELISA) with the samples of the healthy subjects as controls.Statistical analysis was conducted with one-way ANOVA,LSD test and Spearmen's correlation.Results Immunohistochemistry showed that Hsc70 had significantly increased expression in synovial tissues of RA than in the samples of OA and AS.Real-time PCR and western blotting confirmed the above findings.ELISA detected significantly elevated level of Hsc70 in blood of patients with RA as compared with samples from the controls (P＜0.01).Conclusion The study suggests that the up-regulation of Hsc70 may be involved in the pathogenic process of RA.

Objective To determine the best endoscopic treatment for acute obstructive suppurative cholangitis (AOSC).Methods Data of 93 patients who were diagnosed as having AOSC in endoscopic center in the last three years were retrospectively analyzed.All patients were divided into three groups according to the different treatment methods:ENBD group,ENBD+ERBD group and double ERBD group.Postoperative temperature,bilirubin levels and mortality were compared.Results For patients with high level obstruction,incidence of fever in ENBD+ERBD group and double ERBD group were significantly higher than that of ENBD group (1/18 VS 4/10,P ＜ 0.05;0 VS 4/10,P ＜ 0.05).There were no significant differences in incidence of fever(1/18 VS 0) or bilirubin level decrease (17/18 VS 14/15) between ENBD+ERBD group and double ERBD group.For high level obstruction,if the patient had biliary imaging with contrast medium during operation,they would have higher incidence of high fever[(4/10 VS 3.45％ (1/28)] and mortality(3/11 VS 0),lower declining rate of bilirubin level [10/14 VS 96.55％(28/29)] than those without.Conclusion Both left and right hepatic ducts drainage should be recommended for high level biliary obstruction.During the operation,contrast medium should be limited to minimum dose,and should be avoided in high level obstruction cases.Air biliary imaging could be used when necessary.

Objective To evaluate the contrast enhanced perfusion pattern of PTC micro-vascular imaging (MVI) quantitatively.Investigate the correlation between PTC MVI features and CD34 micro-vascular density (MVD).Methods Thirty-nine pathological and clinical confirmed sporadic PTCs were evaluated with real-time gray-scale contrast-ernhanced micro-vascular imaging under a low mechanical index.The micro-bubble agent was SoneVue.Of the 39 PTCs,33 were classical PTCs,6 were PTC with follicular variant (FVPTC).The △ ROI,which is the subtraction of peak echo intensity between the lesion region of interest (ROI) and normal thyroid parenchyma ROI,was used to evaluate the perfusion characteristics of PTC MVI quantitatively.The paraffined specimens were selected for immunohistochemical (IHC) staining for CD3,and the correlation between △ ROI and the CD34 were evaluated.Results △ ROI was strongly correlated with the CD34 expression (P=0.000),significant differences were detected in the distribution pattern of △ ROI value among different CD34 expression levels,no overlapping of the mean △ ROI values and the 95％ confidence intervals was found among the 3 CD34 expression levels.The PTC MVI perfusion was classified into 3 patterns,low perfusion,focal perfiusion and high perfusion,on the basis of combining△ ROI values with the peak ehco pattem in time-intensity curve.Conclusions The △ ROI is strongly correlated with the CD34 expression in papillary thyroid cancer.It can be used for the quantitative evaluation ofPTC MVI pattem and intensity as an objective indicator.

Objective To investigate the efficacy of endoscopy for the treatment of benign biliary stricture after biliary surgery.Methods The clinical data of 127 patients with benign biliary stricture after biliary surgery at the First Hospital of Lanzhou University from January 2007 to December 2011 were retrospectively analyzed.According to the Bismuth classification,there were 60 patients with type Ⅰ,35 with type Ⅱ,21 with type Ⅲ and 11 with type Ⅳ.The efficacies of endoscopy for the treatment of biliary stricture with different Bismuth subtypes were analyzed.Results The location and severity of biliary stricture were confirmed by endoscopic retrograde cholangiopancreatography (ERCP) + cholangiography.Sixteen patients ( including 7 with type Ⅲ and 9 with type Ⅳ) were transferred to surgical treatment due to severe biliary stricture.A total of 111 patients underwent endoscopic treatment successfully,with the success rate of 87.4％ (111/127).The success rates of endoscopy for the treatment of patients with Bismuth Ⅰ,Ⅱ,Ⅲ and Ⅳ biliary strictures were 95％ (57/60),86％ (30/35),9/14and 1/2,respectively.Twenty-nine patients were implanted with retrievable metallic biliary stent,and 82 were implantated with plastic biliary stent.Of the 111 patients,only 6 patients were complicated by acute pancreatitis,and they were cured by conservative treatment.The alleviative rates of yellow skin and icteric sclera,tenderness and distending pain of right upper quadrant,fever were 73％ (81/111 ),83％ (74/89),90％ (73/81 ) and 89％(68/76) at 1 week after treatment,and they were 88％ (98/111),91％ (81/89),94％ (76/81) and 92％(70/76) at 8 weeks after treatment.The efficacy of endoscopy was good in 97 patients and poor in 14 patients,and the 14 patients were converted to open surgery.The symptoms including yellow skin and icteric sclera,tenderness and distending pain of right upper quadrant,fever were completely alleviated at postoperative month 6.Conclusion Endoscopic treatment for benign biliary stricture is safe and effective.

ObjectiveTo investigate the treatment of Mirizzi syndrome (MS) by ERCP、laparoscopy and choledochoscopy. MethodsIn this study 12 cases were confirmed intraoperatively as with MS from July 2005 to June 2009. Patients were treated by ERCP,laparoscopy and choledochoscopy according to the Csendes Classification. ResultThere were 7 MS patients complicating common bile duct stones among all 12 MS cases.There were 8 cases of Type Ⅰ Csendes MS,3 cases of Type Ⅱ and 1case of Type Ⅲ.11cases were treated by the ERCP、laparoscopy and choledochoscope.4 cases was treated by primary closure of common bile duct in laparoscopy,all the patients were cured.The case of type Ⅲ with T tube placed for stone caused bile duct injury had no stricture of the common bile duct as demonstrated by postoperative follow-up cholangiography.ConclusionsERCP,laparoscopy and choledochoscopy are effective for the treatment of Mirizzi syndrome.

Objective To analyze the differences of size and charge heterogeneities between origi-nal humanized anti-TNF-αantibody and four similar biotherapeutic products ( SBP ) .Methods The size exclusion chromatography ( SEC-HPLC ) and weak cation exchange chromatography ( WCX-HPLC ) were used to analyze the size and charge heterogeneities , respectively.Carboxypeptidase B (CpB) treatment was employed to analyze the source of charge heterogeneity of the antibody products .Results Four SBPs showed the same pattern with the originator in SEC-HPLC, and no significant difference with the percentage of mono-mer was observed .The percentages of the aggregates of SBP-3 and SBP-4 were a little higher than those of the originator .The charge distribution of SBPs was significantly different from the originator ′s, especially in the basic region .The results from the samples treated with CpB indicated that the difference of charge distri -bution in the basic region might be caused by the C-terminal lysine variants .Conclusion Four SBPs showed similar size heterogeneity with the originator , but significant differences with charge heterogeneity were observed among them .The study suggested that more attention should be paid to the charge heterogene -ity analysis of the biosimilar products .

Objective To compare the capability of capillary electrophoresis-sodium dodecyl sul-fate ( CE-SDS) and size exclusion-high performance liquid chromatography ( SE-HPLC) for analysis of size heterogeneity of monoclonal antibody products .Methods The size heterogeneity of one humanized anti-VEGF monoclonal antibody was analyzed by using non-reduced and reduced CE-SDS, and conventional , de-natured and denatured reduced SE-HPLC.Results The percentage of aggregates detected by non-reduced CE-SDS (0.82%±0.01%) was equal to that by using denatured SE-HPLC (1.05%±0.02%), but it was significantly lower than that by using conventional SE-HPLC analysis (5.08%±0.10%).With regard to fragments analyzed with non-reduced antibodies, its percentage was (7.12±0.04)% measured by non-re-duced CE-SDS analysis that was significantly higher than that by conventional SE -HPLC analysis (0.02%± 0.01%) and denatured SE-HPLC analysis (0.62%±0.01%).Using reduced antibodies , the percentage of fragments was (3.19±0.50)%tested by reduced CE-SDS analysis that was significantly higher than that by using denatured reduced SE-HPLC analysis (0.07%±0.01%).Conclusion Conventional SE-HPLC was more objective than CE-SDS for content analysis of aggregates , as both the covalent and non-covalent forms of aggregates could be detected .Non-reduced CE-SDS could demonstrate the content of clips , while reduced CE-SDS showed the degraded fragments .Therefore, CE-SDS had an advantage over conventional SE-HPLC for content analysis of fragments .The use of the two analytical methods in combination provided solid techni-cal supports for the quality control of size heterogeneity of monoclonal antibodies .

The biological activity of ADCC by anti-CD20 monoclonal antibody was determined by BioGlo™ Luciferase Assay System using Jurkat/NFAT-luc+FcγRIIIa cell line as effector cell and WIL2-S cell line as target cell. The developed method was verified for specificity, precision and accuracy. Anti-CD20 monoclonal antibody showed a dose-response mode by the developed method, and the determination result complied with the following four-parameter equation: y = (A-D)/[1 + (X/C)(B)] + D. The optimized parameters of the method were determined including the antibodies diluted concentration (18,000 ng·mL(-1)), dilution rate (1:5), the ratio of effector cell and target cell (6:1), and induction time (6 h). The values of eight independent tests have passed a statistical test for curve regression analysis, linear or parallelism, which showed the method possessed good specificity. Four different dilute groups of recovery rates sample were determined for 3 times, and the result showed mean relative potencies of (44.39±3.93)%, (72.74±2.78)%, (128.28±7.01)% and (168.19±2.70)% respectively, with a variation coefficient of less than 10%, and the recoveries of (88.78±7.85)%, (96.99±3.70)%, (102.63±5.61)% and (112.12±1.80)% respectively. A novel reporter gene method for determination of biological activity of ADCC by anti-CD20 monoclonal antibody was successfully developed, which showed strong specificity, good reproducibility and high accuracy, and might be used routinely.

Objective To investigate the efficacy of combined application of laparoscope and multiple endoscopes for the treatment of extra-hepatic bile duct stones.Methods The clinical data of 3780 patients with extra-hepatic bile duct stones who were admitted to the First Hospital of Lanzhou University from March 1998 to June 2010 were retrospectively analyzed.According to the condition of bile duct stones,laparoscope,choledochoscope and duodenoscope were applied separately or combinately.All patients were divided into A,B and C groups.Patients in group A were treated by laparoseopy,choledochoscopy or duodenoscopy;patients in group B were treated by choledochoscopy+duodenoscopy.duodenoscopy+laparoscopy or laparoscopy+choledochoscopy;patients in group C were treated by laparoscopy+duodenoscopy+choledochoscopy.The efficacies of different treatment approaches were analyzed by comparing the results of imaging examination and follow-up.Results The curative rate and complication rate of the group A were 89.54%(1276/1425)and 6.73%(86/1276),respectively.Of the 149 patients in the group A who were failed in the treatment,83 patients were transferred to the group B,and 66 patients were transferred to the group C.The curative rate and complication rate of the group B(including 83 patients transferred from the group A)were 95.93%(1719/1792)and 4.07%(70/1719),respectively,and 73 patients who were failed in the treatment were transferred to the group C.The curative rate and complication rate of the group C(including 139 patients transferred from the group C)were 99.75%(783/785)and 0.26% (2/783),respectively,and 2 patients who were failed in the treatment received open surgery.Conclusion Combined application of laparoscope and endoscopes could raise the success rate of stone clearance and decrease the postoperative complications.