Deckhut A M, Lippolis J D, Tevethia S S
Department of Microbiology and Immunology, Pennsylvania State University College of Medicine, Hershey 17033.
J Virol. 1992 Jan;66(1):440-7. doi: 10.1128/JVI.66.1.440-447.1992.
Simian virus 40 (SV40) tumor (T) antigen expressed in H-2b SV40-transformed cells induces the generation of Lyt-2+ (CD8+) cytotoxic T lymphocytes (CTL), which are involved in tumor rejection, in syngeneic mice. Five CTL recognition sites on T antigen have been described by using mutant T antigens. Four of the sites (I, II, III, and V) are H-2Db restricted and have been broadly mapped with synthetic peptides of 15 amino acids in length overlapping by 5 residues at the amino and carboxy termini. The goal of this study was to define the minimal and optimal amino acid sequences of T antigen which would serve as recognition elements for the H-2Db-restricted CTL clones Y-1, Y-2, Y-3, and Y-5, which recognizes sites I, II, III, and V, respectively. The minimal and optimal residues of T antigen recognized by the four CTL clones were determined by using synthetic peptides truncated at the amino or carboxy terminus and an H-2Db peptide-binding motif. The minimal site recognized by CTL clone Y-1 was defined as amino acids 207 to 215 of SV40 T antigen. However, the optimal sequence recognized by CTL clone Y-1 spanned T-antigen amino acids 205 to 215. The T-antigen peptide sequence LT223-231 was the optimal and minimal sequence recognized by both CTL clones Y-2 and Y-3. Site V was determined to be contained within amino acids 489 to 497 of T antigen. The lytic activities of CTL clones Y-2 and Y-3, which recognize a single nonamer peptide, LT223-231, were affected differently by anti-Lyt-2 antibody, suggesting that the T-cell receptors of these two CTL clones differ in their avidities. As the minimal and optimal H-2Db-restricted CTL recognition sites have been defined by nonamer synthetic peptides, it is now possible to search for naturally processed H-2Db-restricted epitopes of T antigen and identify critical residues involved in processing, presentation, and recognition by SV40-specific CTL.
在H-2b型猴病毒40（SV40）转化细胞中表达的SV40肿瘤（T）抗原，可在同基因小鼠体内诱导产生Lyt-2+（CD8+）细胞毒性T淋巴细胞（CTL），这些CTL参与肿瘤排斥反应。通过使用突变型T抗原，已确定了T抗原上的5个CTL识别位点。其中4个位点（I、II、III和V）受H-2Db限制，并且已使用长度为15个氨基酸、在氨基和羧基末端有5个残基重叠的合成肽进行了大致定位。本研究的目的是确定T抗原的最小和最佳氨基酸序列，这些序列将作为分别识别位点I、II、III和V的H-2Db限制型CTL克隆Y-1、Y-2、Y-3和Y-5的识别元件。通过使用在氨基或羧基末端截短的合成肽以及H-2Db肽结合基序，确定了这4个CTL克隆识别的T抗原的最小和最佳残基。CTL克隆Y-1识别的最小位点被定义为SV40 T抗原的氨基酸207至215。然而，CTL克隆Y-1识别的最佳序列跨越T抗原的氨基酸205至215。T抗原肽序列LT223-231是CTL克隆Y-2和Y-3识别的最佳和最小序列。已确定位点V包含在T抗原的氨基酸489至497内。识别单个九聚体肽LT223-231的CTL克隆Y-2和Y-3的裂解活性受抗Lyt-2抗体的影响不同，这表明这两个CTL克隆的T细胞受体亲和力不同。由于已通过九聚体合成肽确定了最小和最佳的H-2Db限制型CTL识别位点，现在有可能寻找T抗原天然加工的H-2Db限制型表位，并确定参与SV40特异性CTL加工、呈递和识别的关键残基。
