人乳头瘤病毒6b型晚期蛋白L_2免疫反应表位的确定

Mapping the Immunoreactive Epitope Encoding Sequence of HPV6b L_2 ORF

人乳头瘤病毒（ＨＰＶ）含有２个晚期开放读码框（ＯＲＦ），Ｌ＿２ＯＲＦ编码的蛋白具有型特异性。本研究用能表达产生完整ＨＰＶ６ｂＬ＿２蛋白的质粒ｐ６ｂＬ＿２ＮＸ，采取核酸外切酶Ⅲ定向连续次级克隆的方法，制备了一系列一端逐渐删切的ＤＮＡ片段，诱生一组从Ｃ端至Ｎ瑞依次减少的Ｌ＿２蛋白与相应血清作免疫印迹实验，最小的仍保持阳性反应的多肽即含有抗原表位，实验结果ＨＰＶ６ｂＬ＿２蛋白的核酸编码区位于５４８１－５５０６之间，其相应氨基酸序列是ＥＰＧＩＮＰＴＱ。

PV contains two late open reading frames. T he L_2 protein encoded by L_2 ORF possesestype-specific antigenicity. To map the immunoreactive epitope of HPV 6b L_2,a L_2 expressionplasmid p6bL_2 NX was used.Plasmid p6b L_2 NXK was made by adding K pnI linker intopolylinker of p6bL_2 NXK. Unidirectional 3’ to 5’deletions were made in the HPV 6b L_2 ORFinsert of p6b L_2 NXK by using exonuclease Ⅲ and nuclease S_1.The deleted plasmids ex-pressed a set of carboxy to amino terminus truncated fusion proteins. Region containing theimmunoreactive epitope was mapped by determing retained reactivity of the deleted fusionproteins with sera in Western immunoblot assays. The related plasmids were sequuenced.The immunoreactive epiutope was located at 5481-5506 nts region,and the correspondingpepude was EPGINPTQ.