Clinical Laboratory, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
Infect Genet Evol. 2011 Dec;11(8):1940-50. doi: 10.1016/j.meegid.2011.08.015. Epub 2011 Aug 25.
Virus receptors and their expression patterns on the cell surface determine the cell tropism of the virus, host susceptibility and the pathogenesis of the infection. Feline thiamine transport protein 1 (fTHTR1) has been identified as the receptor for feline leukemia virus (FeLV) A. The goal of the present study was to develop a quantitative, TaqMan real-time PCR assay to investigate fTHTR1 mRNA expression in tissues of uninfected and FeLV-infected cats, cats of different ages, in tumor tissues and leukocyte subsets. Moreover, the receptor was molecularly characterized in different feline species. fTHTR1 mRNA expression was detected in all 30 feline tissues investigated, oral mucosa scrapings and blood. Importantly, identification of significant differences in fTHTR1 expression relied on normalization with an appropriate reference gene. The lowest levels were found in the blood, whereas high levels were measured in the oral mucosa, salivary glands and the musculature. In the blood, T lymphocytes showed significantly higher fTHTR1 mRNA expression levels than neutrophil granulocytes. In vitro activation of peripheral blood mononuclear cells with concanavalin A alone or followed by interleukin-2 led to a transient increase of fTHTR1 mRNA expression. In the blood, but not in the examined tissues, FeLV-infected cats tended to have lower fTHTR1 mRNA levels than uninfected cats. The fTHTR1 mRNA levels were not significantly different between tissues with lymphomas and the corresponding non-neoplastic tissues. fTHTR1 was highly conserved among different feline species (Iberian lynx, Asiatic and Indian lion, European wildcat, jaguarundi, domestic cat). In conclusion, while ubiquitous fTHTR1 mRNA expression corresponded to the broad target tissue range of FeLV, particularly high fTHTR1 levels were found at sites of virus entry and shedding. The differential susceptibility of different species to FeLV could not be attributed to variations in the fTHTR1 sequence.
病毒受体及其在细胞表面的表达模式决定了病毒的细胞嗜性、宿主易感性和感染的发病机制。已鉴定出猫硫胺素转运蛋白 1 (fTHTR1) 是猫白血病病毒 (FeLV) A 的受体。本研究的目的是开发一种定量的 TaqMan 实时 PCR 检测法，以研究未感染和 FeLV 感染的猫、不同年龄的猫、肿瘤组织和白细胞亚群中 fTHTR1 mRNA 的表达。此外，还对不同猫种的受体进行了分子表征。在所研究的 30 种猫组织、口腔黏膜刮取物和血液中均检测到 fTHTR1 mRNA 的表达。重要的是，fTHTR1 表达水平的显著差异依赖于与适当的参考基因进行归一化。在血液中检测到的水平最低，而在口腔黏膜、唾液腺和肌肉中检测到的水平最高。在血液中，T 淋巴细胞的 fTHTR1 mRNA 表达水平明显高于中性粒细胞。单独用刀豆蛋白 A 或用白细胞介素-2 激活外周血单个核细胞后，fTHTR1 mRNA 的表达短暂增加。在血液中，但不在检查的组织中，FeLV 感染的猫的 fTHTR1 mRNA 水平比未感染的猫低。在组织学上有淋巴瘤和相应的非肿瘤组织之间，fTHTR1 mRNA 水平无显著差异。fTHTR1 在不同的猫种（伊比利亚猞猁、亚洲狮和印度狮、欧洲野猫、猞猁和家猫）中高度保守。总之，尽管普遍存在的 fTHTR1 mRNA 表达与 FeLV 的广泛靶组织范围相对应，但在病毒进入和脱落的部位发现了特别高的 fTHTR1 水平。不同物种对 FeLV 的不同易感性不能归因于 fTHTR1 序列的变异。
