Mills K H, Skehel J J, Thomas D B
J Exp Med. 1986 Jun 1;163(6):1477-90. doi: 10.1084/jem.163.6.1477.
A panel of H-2k class II-restricted Th clones were established from individual CBA mice primed by infection with X31 influenza virus. 27 clones, which showed specific recognition of the HA surface glycoprotein, were all H3N2 subtype specific, in contrast to a T cell line which was crossreactive and which may have other specificities. 20 distinct HA-specific clones recognized a tryptic cleavage fragment of X31 consisting of residue 28-328 of HA1 (tops) which includes all the Ab-combining regions of the HA molecule. Seven other HA-specific clones failed to respond to either tops or to aggregate (the remainder of the virus after tryptic cleavage of tops). The specificity of these clones has been mapped, tentatively, to a conformational determinant in the interface antibody-binding region of the HA trimer. Analysis of the fine specificity of the HA-specific clones against a panel of H3N2 natural variant viruses isolated from major virus epidemics from 1968 to 1984 revealed a hitherto unrecognized diversity in T cell recognition of a HA. A total of 12 specificity groupings were evident, and varied from groups of clones that recognized all natural variants to one clone that responded only to isolates from 1968 to 1972. Six out of eight clones from a major specificity group, which failed to recognize variants TX/77, BK/79, or CN/84, responded to two overlapping peptides (48-68 and 53-87), corresponding to a region of HA1 that includes part of two antibody combining sites. An examination of the amino acid sequences of natural variant viruses from this region of HA revealed that residues Asn53 and Asn54 and/or Ile62 were critical for recognition by these clones. We conclude that recognition of HA by Th cells is not restricted to a limited number of epitopes in the conserved regions of the molecule, but is extremely diverse and includes specificities that map to variable antibody-combining regions of the molecule. In addition, the sensitivity of the T cell clones to the amino acid substitutions occurring in HA1 of natural variant viruses suggests that Th may play a role in the immune pressure for antigenic variation in the HA molecule.
从感染X31流感病毒致敏的个体CBA小鼠中建立了一组H-2k II类限制性Th克隆。27个对HA表面糖蛋白具有特异性识别的克隆均为H3N2亚型特异性，与之形成对比的是一个具有交叉反应且可能具有其他特异性的T细胞系。20个不同的HA特异性克隆识别X31的一个胰蛋白酶裂解片段，该片段由HA1的28 - 328位残基（顶部）组成，其中包括HA分子的所有抗体结合区域。另外7个HA特异性克隆对顶部片段或聚集物（顶部片段经胰蛋白酶裂解后的病毒剩余部分）均无反应。这些克隆的特异性已初步定位到HA三聚体界面抗体结合区域的一个构象决定簇。对一组针对1968年至1984年主要病毒流行中分离出的H3N2自然变异病毒的HA特异性克隆的精细特异性分析揭示了T细胞对HA识别中迄今未被认识到的多样性。总共出现了12种特异性分组，从识别所有自然变异体的克隆组到仅对1968年至1972年分离株有反应的一个克隆不等。来自一个主要特异性组的8个克隆中有6个不能识别变异体TX/77、BK/79或CN/84，但对两个重叠肽段（48 - 68和53 - 87）有反应，这两个肽段对应于HA1的一个区域，该区域包括两个抗体结合位点的一部分。对来自HA该区域的自然变异病毒的氨基酸序列检查发现，Asn53和Asn54残基和/或Ile62对这些克隆的识别至关重要。我们得出结论，Th细胞对HA的识别不限于分子保守区域中有限数量的表位，而是极其多样的，包括定位到分子可变抗体结合区域的特异性。此外，T细胞克隆对自然变异病毒HA1中发生的氨基酸取代的敏感性表明，Th可能在HA分子抗原变异的免疫压力中起作用。
