ABSTRACT
Objective:To prepare monoclonal antibodies specifically against an immunogenic fragment in ectodomain of prostate-specific membrane antigen ( PSMA ).Methods: An polypeptide immunogenic fragment in the ectodomain of PSMA was predicted by biological information technology,and then it was expressed prokaryotically.BALB/c mice were immunized with the prokar-ytically expressed recombinant polypeptide antigen,to prepare the monoclonal antibodies specifically against an immunogenic fragment in ectodomain of PSMA by hybridoma technology,purification of monoclonal antibody by affinity chromatography,characterization of the monoclonal antibodies by Western blot.The radioimmunoimaging in prostate cancer model was performed by using the labeled McAb.Results:Throught the software analysis,we got the antigen fragment in the ectodomain of PSMA containing 310aa sequences higher specificity, artificially synthesized gene sequence of the region, and constructed a prokaryotic expression vector pET-32a-r-ectodomain-PSMA,by prokaryotic expression we obtained the 50 kD target antigen,after hybridization,the three positive hybridoma cell lines (5E6,4A5 and 4D7) were selected by ELISA using target antigen,the isotypes of 5E6 and 4A5 were IgG2a,the isotypes of 4D7 were IgG1,the titer of three monoclonal antibodies was above 1∶256 000.Western blot results showed that the prepared monoclonal anti-bodies could binding specifically to the antigen in the ectodomain of PSMA.Radioimmunoimaging in prostate cancer animal model results further confirm that the prepared monoclonal antibodies could combinate with the antigen in the ectodomain of PSMA in the animal body, and make the tumor imaging.Conclusion: The prepared monoclonal antibodies can specifically recognizes the PSMA antigen,which laid the foundation for the immunodiagnosis and immunotherapy of prostate cancer.
ABSTRACT
To investigate the risk of papillary thyroid carcinoma (PTC) in patients with nontoxic multinodular goiter (MNG) compared to that in patients with solitary nodule (SN).From Jan 2006 to Dec 2011,761 patients underwent thyroid surgery were included in the retrospective study.According to pathology,patients were subdivided into two groups,MNG and SN.Preoperative thyroid profiles were correlated with patients' postoperative diagnoses.In whole group,the risk of PTC was significantly lower in MNG than in SN (7.09％ vs 15.58％,P =0.000 9).In patients with nontoxic multinodular goiter,the risk of PTC was lower compared to that of those with SN.
ABSTRACT
Objective To study the binding performance of 99Tcm labeled anti-human prostatic specific membrane antigen (PSMA) monoclonal antibody J591 (99Tcm-J591) and prostate cancer cells in vitro,the biodistribution and SPECT imaging of 99Tcm-J591 in nude mice bearing human prostate cancer in vivo.Methods The monoclonal antibody J591 was labeled with 99Tcm by improved Schwarz method.Labeled antibody was purified by Sephadex G-50.The labeling efficiency and radiochemical purity were measured by paper chromatography and trichloroacetic acid method.The binding performance of J591 and prostate cancer cells was measured by flow cytometry in vitro.The nude mice bearing PSMA-positive C4-2 prostate carcinoma xenografts served as experiment group,mice bearing PSMA-negative PC3 tumors served as control group.6.2-8.5 MBq of 99Tcm-J591 (25 μg) was intravenously injected into mice.Gamma imaging was performed 2,6,12 and 24 h after injection,T/NT was calculated by ROI technique.After scanned 12 h post injection,4 mice of the experiment group and 5 mice of the control group were sacrificed and the tracer in vivo biodistribution was measured by gamma-counting,and the ％ ID/g was calculated.Two-sample t test was carried out to validate significant difference of ％ID/g between two groups.Results The labeling efficiency and radiochemieal purity of 99Tcm-J591 were (78.9±6.2)％ and (92.3±5.1)％,respectively,and the specific activity of 99Tcm-J591 was 68.7 MBq/mg.The antibody J591 and 99Tcm-J591 could strongly combine with PSMA-positive C4-2 cells in vitro,and didn't combine with PSMA-negative PC3 cells in vitro.SPECT imaging results showed that radioactive concentration was obvious in tumor 6 h post injection,the concentration scope became large and the tumor image was clear 12 h post injection.T/NT was 1.9±1.1 at 2 h,4.3±1.8 at 6 h,5.6±2.7 at 12 h,1.4±0.6 at 24 h,respectively.In the control group,no radioactivity concentration was found in tumor,and T/NT was less than 2.The biodistribution results showed that ％ID/g of tumor tissue was 20.1±5.2 in the experiment group and 5.8±2.6 in the control group,and there was significant difference (t=5.37,P＜0.001).No significant tracer uptake occurred in other tissues and organs between the two groups (all t＜ 1.98,all P＞0.05).Conclusion The immunoactivity,characteristics of biodistribution and tumor targeting property of monoclonal antibody J591 show promising future and potential values in diagnosis and therapy of prostate cancer.