Kuwano K, Scott M, Young J F, Ennis F A
Department of Medicine, University of Massachusetts Medical School, Worcester 01655.
J Immunol. 1988 Feb 15;140(4):1264-8.
Influenza H1 subtype-specific CTL can be induced by secondary stimulation of a hybrid protein of the first 81 amino acids of the viral NS1 non-structural protein and the HA2 subunit of A/Puerto Rico/8/34(H1N1) hemagglutinin. In addition, a derivative of this protein with 65 amino acids deleted from the N-terminal end of HA2 can also generate H1 subtype-specific CTL in bulk cultures. CTL clones established by stimulation with the derivative protein demonstrated cross-reactive lysis of target cells infected with virus strains of the H1 and H2 subtypes. Cold target competition experiments with CTL clones as effectors demonstrated that the Ag specificity between these two hybrid proteins is identical. Adoptive transfer of the CTL clone significantly reduced virus titers in the lungs of mice infected with the virus strains of the H1 or H2 subtype but not those infected with the H3 subtype virus in vivo, which reflects the in vitro CTL clone activity. These experiments demonstrate that an epitope on the hemagglutinin that is conserved on virus strains of the H1 and H2 subtypes induces a protective CTL response. These results suggest an alternative approach for developing influenza vaccines by using conserved antigenic sites on the hemagglutinin HA2 subunit to avoid the problem of frequent antigenic mutations of the HA1 subunit antibody binding sites.
甲型流感病毒H1亚型特异性细胞毒性T淋巴细胞（CTL）可通过对病毒非结构蛋白NS1的前81个氨基酸与A/波多黎各/8/34（H1N1）血凝素的HA2亚基的杂合蛋白进行二次刺激来诱导产生。此外，该蛋白的一种衍生物，其HA2的N末端缺失65个氨基酸，在批量培养中也能产生H1亚型特异性CTL。用该衍生物蛋白刺激建立的CTL克隆对感染H1和H2亚型病毒株的靶细胞表现出交叉反应性裂解。以CTL克隆作为效应细胞的冷靶竞争实验表明，这两种杂合蛋白之间的抗原特异性是相同的。在体内，CTL克隆的过继转移显著降低了感染H1或H2亚型病毒株小鼠肺内的病毒滴度，但对感染H3亚型病毒的小鼠则无此作用，这反映了体外CTL克隆的活性。这些实验表明，H1和H2亚型病毒株血凝素上保守的一个表位可诱导产生保护性CTL反应。这些结果提示了一种开发流感疫苗的替代方法，即利用血凝素HA2亚基上保守的抗原位点，以避免HA1亚基抗体结合位点频繁发生抗原变异的问题。
