中文摘要：

目的：预测及鉴定尤文肉瘤EWS-FLI1融合蛋白的B淋巴细胞表位。方法：采用综合法预测EWS-FLI1蛋白的二级结构及B淋巴细胞表位,运用标准Fmoc方案合成预测的表位肽,HPLC和MS进行表位肽的纯度分析及分子量鉴定,ELISA法检测表位肽的抗原性,并测定表位肽特异性免疫血清效价,Western blot鉴定免疫血清与EWS-FLI1蛋白亲合力。结果：通过综合法预测得到3个高分值的B淋巴细胞表位,HPLC分析合成的表位肽纯度〉85%,MS鉴定表位肽的分子量无误,ELISA法检测证实3个B淋巴细胞表位肽均可获得强的抗原抗体反应,其中表位肽P2的抗原性最强,在1∶40时A450=2.46,达到最高,1∶10 240稀释后抗原抗体反应仍呈阳性;用这3个B淋巴细胞表位肽免疫新西兰兔也能获得理想的抗体效价,其中表位肽P2获得的抗体效价最高,1∶512 000稀释时A450=1.11;Western blot鉴定表位肽P1、P2免疫血清能够结合EWS-FLI1蛋白。结论：尤文肉瘤EWS-FLI1蛋白的B淋巴细胞表位肽P1、P2具有潜在的抗原性和免疫原性。

英文摘要：

Objective：To predict and identify the B-lymphocyte epitopes of Ewing＇s sarcoma EWS-FLI1 fusion protein.Methods：The secondary structure and B-lymphocyte epitopes of EWS-FLI1 protein were comprehensively predicted by comprehensive algorithm;epitope peptides were synthesized according to standard Fmoc proposal,purified by high performance liquid chromatography（HPLC） and identified by mass spectrometry（MS） to validate the molecular weight.Antigenicity of peptides and the sera titer of were evaluated by ELISA;the affinities of anti-peptides sera to EWS-FLI1 protein were identified by Western blot.Results：Three B-lymphocyte epitopes were screened out according to comprehensive algorithm.HPLC analysis confirmed the purity of any synthesized epitope peptides was more than 85% at least and MS analysis validated the molecular weights of them accorded respectively to their theoretical values.All three epitope peptides induced obvious antigen-antibody reactions,among which epitope peptide 2（P2） did the most;the Absorbance 450 nm at the time of P2 immunoreacting with rabbit antiserum after 3rd EWS-FLI1 immunization increased to the apical value of 2.46 at the reacting titer of 1∶40,and the immunoreaction was still positive at the dilution titer of 1∶10 240;the titer of all 3 epitope peptides antiserum could increased gradually with the continuous increasing times of immunization to New Zealand white rabbit.The Absorbance 450 nm at the time of P2 immunoreacting with rabbit antiserum after 4th P2 immunization was still 1.11 at the dilution titer of 1∶512 000.Western blot analysis confirmed that anti-P1 and anti-P2 rabbit sera could bind to EWS-FLI1 protein.Conclusion：The B-lymphocyte epitopes peptides（P1 and P2） derived from EWS-FLI1 fusion protein of Ewing＇s Sarcoma have potential antigenicity and immunogenicity.