Forlenza Maria, de Carvalho Dias João D A, Veselý Tomas, Pokorová Dagmar, Savelkoul Huub F J, Wiegertjes Geert F
Department of Animal Sciences, Cell Biology and Immunology Group, Wageningen Institute of Animal Sciences, Wageningen University, PO Box 338, 6700 AH, Wageningen, The Netherlands.
Mol Immunol. 2008 Mar;45(6):1531-47. doi: 10.1016/j.molimm.2007.10.010. Epub 2007 Nov 19.
Mammalian naïve CD8+ T cells are activated by antigen (signal 1) and CD28 costimulation (signal 2) to undergo several rounds of cell division, but programming for survival, effector function and memory requires a third signal that can be provided by IL-12 and/or type I interferons. Functional studies indicate that the route of antigen presentation and costimulation are conserved from fish to mammals. However, the potential of IL-12 and IFN alpha beta to act as signal-3 cytokines in infections inducing a CTL response has not been examined in fish. We report the cloning of CD8 alpha and CD8 beta homologues, each present in duplicate copies and of two TCR-C alpha isoforms in European common carp. The identification of (cytotoxic) T cell marker sequences and the availability of sequences coding for the signal-3 cytokines in the same fish species, allowed us to investigate by RT-qPCR their kinetics of gene expression during viral and parasitic infection. Our results show that transcription of signal-3 cytokines occurred concomitantly with CD8 alpha beta up-regulation exclusively at 4 days post-primary viral infection. No regulation of IL-12 and IFN alpha beta was observed after parasitic infection. Our data provide evidences for an evolutionary conservation of function for IL-12 and IFN alpha beta to act as third signal during CTL activation. In addition, we suggest that a CD8 alpha 2/beta1 and a p35p40b association could be the preferred combinations for the formation of a functional CD8 co-receptor and an IL-12p70 heterodimer during viral infection. The relevance of our findings to future vaccination strategies in fish is discussed.
哺乳动物的初始CD8 + T细胞通过抗原（信号1）和CD28共刺激（信号2）被激活，从而进行几轮细胞分裂，但细胞存活、效应器功能和记忆的编程需要由IL - 12和/或I型干扰素提供的第三个信号。功能研究表明，从鱼类到哺乳动物，抗原呈递和共刺激的途径是保守的。然而，在鱼类中尚未研究IL - 12和IFNαβ在诱导CTL反应的感染中作为信号3细胞因子的潜力。我们报告了欧洲鲤鱼中CD8α和CD8β同源物的克隆，每种均有两个拷贝，以及两种TCR - Cα异构体。在同一鱼类物种中鉴定出（细胞毒性）T细胞标志物序列以及信号3细胞因子的编码序列，使我们能够通过RT - qPCR研究它们在病毒和寄生虫感染期间的基因表达动力学。我们的结果表明，信号3细胞因子的转录仅在初次病毒感染后4天与CD8αβ上调同时发生。寄生虫感染后未观察到IL - 12和IFNαβ的调节。我们的数据为IL - 12和IFNαβ在CTL激活过程中作为第三信号的功能进化保守性提供了证据。此外，我们建议CD8α2 /β1和p35p40b组合可能是病毒感染期间形成功能性CD8共受体和IL - 12p70异二聚体的首选组合。讨论了我们的发现与未来鱼类疫苗接种策略的相关性。
