Aldrich C J, DeCloux A, Woods A S, Cotter R J, Soloski M J, Forman J
Department of Microbiology, University of Texas Southwestern Medical Center at Dallas 75235-9048.
Cell. 1994 Nov 18;79(4):649-58. doi: 10.1016/0092-8674(94)90550-9.
Recognition of the class Ib antigen Qa-1 by a portion of alloreactive cytotoxic T lymphocyte (CTL) clones requires that the target cell express a second gene, termed Qa-1 determinant modifier (Qdm). We show that Qdm is identical to most D allele genes, excepting Dk, and that a nonamer peptide derived from D alloantigens restores CTL recognition on cells that lack the Qdm-encoded determinant. The equivalent Dk peptide has an Ala-->Val interchange at P3 and requires approximately 4 logs more peptide than the AlaP3 peptide for target cell lysis. Two of five CTL clones, not dependent on Qdm for target cell recognition, also recognize the Qdm peptide as well as the ValP3 variant. Although the Qdm peptide spans residues 3-11 from the leader, it requires the Tap transporters for its expression. Thus, the response against this class Ib molecule provides a tool for dissecting alloreactivity as well as pathways for antigen presentation.
一部分同种异体反应性细胞毒性T淋巴细胞（CTL）克隆对Ib类抗原Qa-1的识别要求靶细胞表达另一个基因，称为Qa-1决定簇修饰因子（Qdm）。我们发现Qdm与大多数D等位基因相同，但不包括Dk，并且源自D同种异体抗原的九聚体肽可恢复缺乏Qdm编码决定簇的细胞上的CTL识别。等效的Dk肽在P3处有一个丙氨酸到缬氨酸的互换，并且与丙氨酸P3肽相比，靶细胞裂解所需的肽量大约多4个对数。五个CTL克隆中有两个不依赖Qdm进行靶细胞识别，它们也识别Qdm肽以及ValP3变体。尽管Qdm肽跨越前导序列的3至11位残基，但它的表达需要Tap转运体。因此，针对这种Ib类分子的反应为剖析同种异体反应性以及抗原呈递途径提供了一个工具。
