Kulkarni A B, Morse H C, Bennink J R, Yewdell J W, Murphy B R
Respiratory Viruses Section, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892.
J Virol. 1993 Jul;67(7):4086-92. doi: 10.1128/JVI.67.7.4086-4092.1993.
The M2 protein of respiratory syncytial virus (RSV) is a protective antigen in H-2d, but not H-2b or H-2k mice. None of the other RSV proteins, excluding the surface glycoproteins that induce neutralizing antibodies, is protective in mice bearing these haplotypes. Thus, the M2 protein stands alone as a nonglycoprotein-protective antigen of RSV. The M2 protein is a target for murine Kd-restricted cytotoxic T lymphocytes (CTLs), and the resistance induced by infection with a vaccinia virus-RSV M2 (vac-M2) recombinant is mediated by CD8+ CTLs. Since the nonameric consensus sequence for H-2 Kd-restricted T-cell epitopes and the amino acid sequence of the M2 protein of subgroup A and B strains of RSV are known, the present study sought to identify the specific epitope(s) on the M2 protein recognized by CD8+ CTLs. This was done by examining the ability of four predicted Kd-specific motif peptides present in the M2 amino acid sequence of an RSV subgroup A strain to sensitize target cells for lysis by pulmonary or splenic CTLs obtained from mice infected with RSV or vac-M2. The following observations were made. First, two of the four peptides sensitized target cells for lysis by pulmonary or splenic CTLs induced by infection with either vac-M2 or RSV. Second, one of the two peptides, namely the 82-90 (M2) peptide, sensitized targets at a very low peptide concentration (10(-10) to 10(-12) M). Third, cold-target competition experiments revealed that the predominant CTL population induced by infection with vac-M2 or RSV recognized the 82-90 (M2) peptide, and this CTL population appeared to recognize the 71-79 (M2) peptide in a cross-reactive manner. Fourth, CTL recognition of targets sensitized with either the 71-79 (M2) or the 82-90 (M2) peptide was Kd restricted. Fifth, CTLs induced by infection with RSV subgroup A or B strains recognized the two M2 peptides. The findings suggest that the M2 protein of RSV contains an immunodominant Kd-restricted CTL epitope consisting of amino acid residues 82 to 90 (SYIGSINNI), which are shared by subgroup A and B RSVs.
呼吸道合胞病毒（RSV）的M2蛋白在H-2d小鼠中是一种保护性抗原，但在H-2b或H-2k小鼠中则不是。除了诱导中和抗体的表面糖蛋白外，其他RSV蛋白在携带这些单倍型的小鼠中均无保护作用。因此，M2蛋白是RSV唯一的非糖蛋白保护性抗原。M2蛋白是小鼠Kd限制性细胞毒性T淋巴细胞（CTL）的靶标，牛痘病毒-RSV M2（vac-M2）重组体感染诱导的抗性由CD8 + CTL介导。由于已知H-2 Kd限制性T细胞表位的九聚体共有序列以及RSV A组和B组毒株M2蛋白的氨基酸序列，本研究旨在鉴定CD8 + CTL识别的M2蛋白上的特定表位。这是通过检测RSV A组毒株M2氨基酸序列中存在的四种预测的Kd特异性基序肽使靶细胞对从感染RSV或vac-M2的小鼠获得的肺或脾CTL裂解敏感的能力来完成的。得出了以下观察结果。首先，四种肽中的两种使靶细胞对由vac-M2或RSV感染诱导的肺或脾CTL裂解敏感。其次，两种肽中的一种，即82-90（M2）肽，在非常低的肽浓度（10^-10至10^-12 M）下使靶细胞敏感。第三，冷靶竞争实验表明，由vac-M2或RSV感染诱导的主要CTL群体识别82-90（M2）肽，并且该CTL群体似乎以交叉反应方式识别71-79（M2）肽。第四，CTL对用71-79（M2）或82-90（M2）肽致敏的靶标的识别是Kd限制性的。第五，由RSV A组或B组毒株感染诱导的CTL识别这两种M2肽。这些发现表明，RSV的M2蛋白含有一个免疫显性的Kd限制性CTL表位，由氨基酸残基82至90（SYIGSINNI）组成，A组和B组RSV共有。
