应用噬菌体展示技术筛选人巨细胞病毒糖蛋白M新的中和抗原表位

人巨细胞病毒(HCMV)糖蛋白复合物Ⅱ包括两种蛋白，即糖蛋白M(gM)和糖蛋白N(gN)．尽管来自于HCMV阳性病人血清中的糖蛋白复合物Ⅱ的IgG抗体能够中和HCMV粒子，但迄今为止，还没有gM中和性抗原表位的相关研究．应用消减杂交技术，通过噬菌体肽库筛选获得gM抗原的一个表位，即MAD．MAD氨基酸序列与gM第32～38位序列高度同源．将MAD与钥孔血蓝蛋白偶联免疫小鼠可产生抗MAD多抗，该多抗不仅结合天然HCMV病毒粒子，而且特异结合重组表达的gM30～78多肽．ELISA结果表明MAD能够特异结合HCMV阳性的病人血清．病毒中和实验结果进一步证明抗MAD多抗能够抑制HCMV AD169株病毒感染人胚肺细胞．总之，MAD表位有可能成为HCMV病毒疫苗潜在的保护性抗原.

A Novel Neutralizing Epitope of Human Cytomegalovirus Glycoprotein M Screened by Phage Display

Human cytomegalovirus glycoprotein complex Ⅱ (gC Ⅱ ) consists of two glycoproteins, gM and gN. Although gC Ⅱ specific IgG purified from HCMV positive patient sera can neutralize HCMV, there has been no report on the generation of virus-neutralizing antibodies by immunizing with one epitope of gM. The epitope, termed MAD, was screened from random phage peptide library by subtractive strategy. The peptide sequence of MAD was highly homologous with 32~38 amino acids of HCMV gM. Mice immunized with MAD coupled with keyhole limpet hemocyanin (KLH) could produce specific antibodies against MAD, and the antibodies obtained could bind not only native HCMV particles, but also the recombinant gM30～78 peptide. ELISA analysis results showed that MAD could specifically bind HCMV-positive human serum samples. Virus-neutralizing assay results demonstrated that the antibodies against MAD could inhibit HCMV strain AD169 entering the human embryonic lung cells. The results suggested that MAD could be used as a new potential protective antigen in the development of HCMV vaccine.