The Preparation And Partial Characteristic Analysis Of ¹³¹I Isotope Labeled GM-CSF

Objictive To exploit the techniques of producing ¹³¹I-GM-CSF,observe thespecific binding and specific cytotoxicity when ¹³¹I-GM-CSF acting with AML celllines;to investigate a brand new stratigy of targeted therapy through the mediation ofGMCSF/GMR system,provide the fundamental theory for the possible clinicalapplication in the future.Methods GM-CSF was labelled with ¹³¹I isotope by chloamin-T mothod,purified by column chromatography.¹³¹I-GM-CSF's radiochemical purity and stabilitywere detected by TCA settling method.TF-1,HL-60 and K562 cell sruface respectivelyhave a high,middle and low level of GMR.We respectively detected the uptakeefficiency of ¹³¹I-GM-CSF and Na¹³¹I by three cell lines,and respectively measuredGMR- mediated internalization.We used MTT assay to detect the survival rate andIC50 when ¹³¹I-GM-CSF,Na¹³¹I and GM-CSF respectively acted with three kinds ofleukemia cell lines with different level GMR.Resultsâ‘ The labelling rate of ¹³¹I-GM-CSF was 60～75%,avergae 65%,radiochemical purity was 98% on the first day,after 4-days storage at 4℃,itsradiochemical purity still remained over 85%.â‘¡Three cell lines had no uptake ofNa¹³¹I,and had various uptake of ¹³¹I-GM-CSF。From 30 min to 4 h,the uptake rate of¹³¹I-GM-CSF by TF-1 was 0.8533～1.4412% ,HL-60 group was 0.4368～0.8696%,K562 group was 0.0870～0.2406%.â‘¢The internalization of TF-1 was highest amongthree leukemic cell lines,Max 8.5%,Mix 20.2%.To HL-60 cell group,its maximuminternalization was 27.3%,minimum was 14.7%.K562 group was lowest,itsinternalization was about 2.8%～10.4%.â‘£When TF-1,HL-60 and K562 were respectively treated with ¹³¹I-GM-CSF,their IC50 were 6.98μci/ml,3.22μci/ml and9.85μci/ml,when treated with Na¹³¹I,there IC50 were 6.82μci/ml,11.03μci/ml and10.86μci/ml.When radioactive concentration was < 2.5μci/ml,the survival rate ofTF-1 when treated by ¹³¹I-GM-CSF was lower than when treated by Na¹³¹I(p<0.05);when radioactive concentration < 12.5μci/ml,the survival rate of HL-60 group whentreated by ¹³¹I-GM-CSF was lower than when treated by Na¹³¹I(p<0.05);the survivalrate of K562 group had no significant difference when treated by either ¹³¹I-GM-CSF orNa¹³¹I(p>0.05).Conclusionâ‘ We can obtain ¹³¹I-GM-CSF with high radiochemical purity,goodstability and high immunoactivity through chloamin-T method.â‘¡The cell lines withhigh level GMR can specifically uptake more ¹³¹I-GM-CSF and internalize more GMRthan ones with low level,which shows that ¹³¹I-GM-CSF can targetedly bind to celllines according to GMR expression level of cell surface.â‘¢Among some certainradioactive concentration,¹³¹I-GM-CSF has stronger cytotoxicity to leukemic cell lineswith high level than Na¹³¹I which showed that ¹³¹I-GM-CSF may be available intargeted therapy of AML.