A血型单克隆抗体的抗原结合部位结构多样性研究

应用杂交瘤技术，以Ａ型红细胞，Ａ１血型物质ＭＳＭ（Ａ１）和Ａ－ＲＢＣ＋ＭＳＭ（Ａ１）为免疫原，制备了一组抗人Ａ血型单克隆抗体：Ａ１２１８，Ｂ５７，ＤＥ９２３－Ｇ８，Ｄ２８６－Ｅ１２经Ｔａｋａｔｓｙ微量血细胞凝集试验证明：这组单抗仅能凝集Ａ１，Ａ２及ＡＢ型红细胞，不能凝集Ｂ，Ｏ型红细胞．采用ＥＬＩＳＡ定量抑制试验法，精确测定了它们抗原结合部位的结构，互补于Ａ活性寡糖。Ａ１２１８互补于具有双岩藻糖结构的Ａ活性五糖（Ａ－Ｐｅｎｔａ）；Ｂ５７，ＤＥ９２３－Ｇ８互补于具有单岩藻糖结构的Ａ活性六糖（Ａ－Ｈｅｘａ）；而Ｄ２８６－Ｅ１２则互补于具有单岩藻糖的Ａ活性四糖（Ａ－Ｔｅｔｒａ）．结果表明：血凝特异性相同的抗Ａ单抗，其抗原结合部位的结构可呈现多样性。即Ａ活性寡糖的糖基组成数目和含有岩藻糖数目均可不相同，各种抑制剂对不同单抗的抑制作用强弱也不相同。

Study on Structure Multiplicity of Combining Site of Monoclonal Antibody-Antigen to Blood Group A

Using hybridoma technique.a group of monoclonal antibodies type A to blood group A(A1218,B57,DE923-G8,and D286-E12) were prepared with type A erythrocytes,blood group substances A1 MSM(A1) and A-RBC MSM(A1) as antigens,respectively.It was demonstrated that they could only agglutinate A1-,A2-and AB-type erythrocytes,but could not agglutinate B-and O-type erythrocytes by Takatsy microtitration assays.The complemental structures of their antibody antigen combining sites were determined to be complementary to A-active oligosaccharides by ELISA quantitative inhibition assay.A1218 was complementary to A-Penta,having difucosyl structure.B57 and DE923-G8 were complementary to A-Hexa,having monofucosyl structure.D286-E12 was complementary to A-Tetra,having monofucosyl structure.The results showed that for the antibodies having some hemagglatination-specificity.complementary structures of their antibody-antigen combining sites appear in multiple forms.i.e.the oligosaccharide and fucosyl number in A-active-oligosaccharide may be different and the inhibition degree and inhibition order by A-active oligosaccharide are also not the same.