Noppen C, Schaefer C, Zajac P, Schütz A, Kocher T, Kloth J, Heberer M, Colonna M, De Libero G, Spagnoli G C
Department of Surgery, University of Basel, Switzerland.
Eur J Immunol. 1998 Apr;28(4):1134-42. doi: 10.1002/(SICI)1521-4141(199804)28:04<1134::AID-IMMU1134>3.0.CO;2-G.
C-type lectin-like inhibitory receptors are heterodimers consisting of CD94 and NKG2-A-B molecules expressed on NK cells and on a subset of activated T lymphocytes. Their inhibitory effects on NK cytotoxicity and on the NK-like activity of T cell clones have been demonstrated, but no data are currently available on antigen-specific class I-restricted cytotoxic T lymphocytes (CTL). We have generated a panel of HLA-A2.1-restricted CTL clones directed against a nonapeptide derived from a melanoma-associated antigen, dopachrome tautomerase (TRP-2). All clones were CD8+ and TCR alphabeta+. About half of them expressed a CD94bright phenotype, whereas the remaining were CD94dim. Only the CD94bright CTL expressed the NKG2-A-B gene, consistent with the expression of a C-type, lectin-like, inhibitory CD94/NKG2-A-B heterodimer. Both CD94bright and CD94dim clones appeared to require similar amounts of synthetic epitope sensitizing target cells. Addition of anti-CD94 mAb resulted in a significant increase of specific killing by CD94bright, but not by CD94dim clones in the presence of suboptimal concentrations of peptide, whereas, when optimal amounts were used, the mAb did not induce a significant modulation of the cytotoxicity. Antigen-induced inward [Ca2+]i fluxes were unaffected, but an enhancement of TCR down-modulation could be observed in the presence of anti-CD94 mAb at high concentration of antigenic peptide. The analysis of the TCR-Vbeta repertoire of the CTL clones by RT-PCR and immunofluorescence revealed that all clones regardless of CD94 phenotype shared Vbeta22 expression. Most importantly, sequence analysis showed that they all expressed identical Vbeta22 TCR rearranged with Jbeta2.1 and Cbeta2. Taken together, these data indicate that different expression of functionally active lectin-like inhibitory receptors can be detected in CTL clones sharing identical TCR sequence and peptide specificity.
C型凝集素样抑制性受体是异二聚体，由表达于自然杀伤细胞（NK细胞）和一部分活化T淋巴细胞上的CD94和NKG2 - A - B分子组成。它们对NK细胞毒性以及T细胞克隆的NK样活性的抑制作用已得到证实，但目前尚无关于抗原特异性I类限制性细胞毒性T淋巴细胞（CTL）的相关数据。我们已构建了一组针对源自黑色素瘤相关抗原多巴色素互变异构酶（TRP - 2）的九肽的HLA - A2.1限制性CTL克隆。所有克隆均为CD8 + 且TCRαβ + 。其中约一半表现为CD94高表达表型，而其余的为CD94低表达。只有CD94高表达的CTL表达NKG2 - A - B基因，这与功能性C型凝集素样抑制性CD94 / NKG2 - A - B异二聚体的表达一致。CD94高表达和CD94低表达的克隆似乎都需要相似量的合成表位来致敏靶细胞。添加抗CD94单克隆抗体导致在肽浓度次优的情况下，CD94高表达克隆的特异性杀伤显著增加，但CD94低表达克隆则不然；而当使用最佳量的肽时，该单克隆抗体并未引起细胞毒性的显著调节。抗原诱导的内向[Ca2 + ]i通量未受影响，但在高浓度抗原肽存在的情况下，抗CD94单克隆抗体存在时可观察到TCR下调增强。通过逆转录聚合酶链反应（RT - PCR）和免疫荧光对CTL克隆的TCR - Vβ谱进行分析，结果显示所有克隆无论CD94表型如何均共同表达Vβ22。最重要的是，序列分析表明它们均表达与Jβ2.1和Cβ2重排的相同Vβ22 TCR。综上所述，这些数据表明在具有相同TCR序列和肽特异性的CTL克隆中可检测到功能性凝集素样抑制性受体的不同表达。
