Goday A, Simmonds H A, Morris G S, Fairbanks L D
Clin Exp Immunol. 1984 Apr;56(1):39-48.
Enzyme inhibitors used to simulate the inherited immunodeficiency diseases, adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) deficiency, have been assessed in cultured human lymphocytes. Only 2'-deoxycoformycin (dCF) completely inhibited ADA in T and B cells at concentrations in excess of 5 microM. Erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA) and 8-amino guanosine (8-NH2GR) did not inhibit ADA or PNP completely at any concentration. Detailed metabolic experiments comparing viability and deoxynucleotide accumulation showed that B cell lines of malignant origin also accumulated high levels of dATP from 2'-deoxyadenosine (dAR), and dGTP from 2'-deoxyguanosine (dGR) as effectively as T cells--even without inhibitors, however, dAR reduced cell viability only when ADA was inhibited by dCF, whilst dGR was equally toxic with or without inhibitor, even to a line which accumulated no dGTP. These experiments indicate that cultured lymphocytes, using either EHNA or 8-NH2GR as enzyme inhibitor, are not valid models of the toxicity to the immune system in inherited ADA or PNP deficiency. They demonstrate that the ability to accumulate high levels of dATP or dGTP is not exclusive to T cells and that the in vitro toxicity of dAR or dGR could relate to the use of excess substrate and/or accumulation in different nucleotide, not deoxynucleotide pools.
用于模拟遗传性免疫缺陷疾病——腺苷脱氨酶（ADA）和嘌呤核苷磷酸化酶（PNP）缺乏症的酶抑制剂，已在培养的人淋巴细胞中进行了评估。只有2'-脱氧助间型霉素（dCF）在浓度超过5 microM时能完全抑制T细胞和B细胞中的ADA。在任何浓度下，赤型-9-(2-羟基-3-壬基)腺嘌呤（EHNA）和8-氨基鸟苷（8-NH2GR）都不能完全抑制ADA或PNP。比较细胞活力和脱氧核苷酸积累的详细代谢实验表明，恶性起源的B细胞系也能像T细胞一样有效地从2'-脱氧腺苷（dAR）积累高水平的dATP，从2'-脱氧鸟苷（dGR）积累dGTP——然而，只有当ADA被dCF抑制时，dAR才会降低细胞活力，而无论有无抑制剂，dGR都具有同等毒性，甚至对一个不积累dGTP的细胞系也是如此。这些实验表明，使用EHNA或8-NH2GR作为酶抑制剂的培养淋巴细胞，不是遗传性ADA或PNP缺乏症对免疫系统毒性的有效模型。它们表明，积累高水平dATP或dGTP的能力并非T细胞所独有，并且dAR或dGR的体外毒性可能与过量底物的使用和/或在不同核苷酸而非脱氧核苷酸池中的积累有关。
