Davila D R, Guilmette R A, Bice D E, Muggenburg B A, Swafford D S, Haley P J
Inhalation Toxicology Research Institute, Lovelace Biomedical and Environmental Research Institute, Inc., Albuquerque NM 87185.
Int J Radiat Biol. 1992 Jan;61(1):123-33. doi: 10.1080/09553009214550691.
Young Beagle dogs were exposed by inhalation to aerosols of 239PuO2 and observed for their lifespans as part of a large, ongoing study of the biological effects of inhaled radionuclides. The purpose of our study was to compare certain immune responses of the 239PuO2-exposed dogs at middle age (7-10 years old) and old age (12-14 years old), with those of unexposed, age-matched or young (3-4 years old) animals. Some of the aged, exposed dogs had developed lung tumours. Lymphocyte proliferative responses to phytohaemagglutinin (PHA) were lower in aged control dogs than in either young or middle-aged control dogs. Both aged and middle-aged, radiation-exposed dogs had decreased responses to PHA when compared to age-matched controls. Responses to concanavalin A (Con A) were not affected by age in control dogs, but tended to decrease in the oldest group of radiation-exposed dogs. Responses to both PHA and Con A were severely depressed in tumour-bearing dogs. The cytolytic activity of natural killer cells was not affected by age, radiation exposure, or tumour presence. We concluded that inhalation of 239PuO2 by young Beagle dogs resulted in an earlier-than-normal decrease in the ability of T cells to respond to mitogenic stimulation. In other words the depressed responses to PHA that were observed might represent radiation-induced, accelerated ageing of the T cell response.
作为一项正在进行的关于吸入放射性核素生物学效应的大型研究的一部分，幼年比格犬通过吸入239PuO2气溶胶进行暴露，并对其寿命进行观察。我们研究的目的是比较中年（7 - 10岁）和老年（12 - 14岁）的239PuO2暴露犬与未暴露的、年龄匹配或年轻（3 - 4岁）动物的某些免疫反应。一些老年的暴露犬出现了肺部肿瘤。老年对照犬对植物血凝素（PHA）的淋巴细胞增殖反应低于年轻或中年对照犬。与年龄匹配的对照犬相比，老年和中年的辐射暴露犬对PHA的反应均降低。对照犬对刀豆球蛋白A（Con A）的反应不受年龄影响，但在最老的一组辐射暴露犬中趋于降低。荷瘤犬对PHA和Con A的反应均严重降低。自然杀伤细胞的细胞溶解活性不受年龄、辐射暴露或肿瘤存在的影响。我们得出结论，幼年比格犬吸入239PuO2导致T细胞对有丝分裂原刺激的反应能力比正常情况更早下降。换句话说，观察到的对PHA反应降低可能代表辐射诱导的T细胞反应加速老化。
