C-myc标记肽对单链抗体与抗原结合活性的影响

目的 探讨在不同的免疫学检测方法中，与单链抗体相连的亲和标记肽对单链抗体与抗原结合活性的影响。方法 在制备“VH-连接链-VL”型结构抗乙酰胆碱受体单链抗体时，将c-myc标记肽与单链抗体的VL连接，应用先将抗c-myc抗体固定单链抗体的固相放射免疫测定法、直接将单链抗体与乙酰胆碱受体结合的液相放射免疫测定法，分别测定单链抗体与乙酰胆碱受体的结合活性。结果 在固相放射免疫测定法中，单链抗体不能与乙酰胆碱受体结合；在液相放射免疫测定法中，单链抗体则能与乙酰胆碱受体结合。结论 在应用不同的免疫学检测方法中，与单链抗体相连的c-myc标记肽可影响单链抗体与抗原的结合活性。

Effects of c-myc tag on binding activity of single chain antibody fragments to antigens

Objective To investigate the affects of affinity tag on binding activity of single chain variable fragment (ScFv) to antigen using different immunological assays. Methods A c-myc tag was conjugated to C-terminus of V L in the V H-linker-V L of ScFv against acetylcholine receptor (AChR). Solid phase radioimmunoassay (SPRIA), in which the ScFv was first caught by fixed anti-c-myc antibody, and radioimmunoassay (RIA), in which the ScFv was directly bound to AChR, were used to determine the binding activity of the ScFv to AChR. Results The ScFv could not bind to AChR in SPRIA, whereas it was able to bind to AChR in RIA. Conclusion Affinity tag conjugated to ScFv may interfere with the binding activity of ScFv to antigen in different immunological assays.