Fujiwara Megumi, Yonezawa Tomohiro, Arai Toshiro, Yamamoto Ichiro, Ohtsuka Hiromichi
Laboratory of Veterinary Biochemistry, Nippon Veterinary and Life Science University, Tokyo, Japan.
Laboratory of Large Animal Internal Medicine,
Vet Med (Auckl). 2012 Aug 24;3:79-84. doi: 10.2147/VMRR.S32590. eCollection 2012.
The immune system is considered to be affected by aging, which is linked to various immune pathogeneses. The purpose of this study was to determine age-associated changes in immune function of healthy dogs (beagles), specifically those of naive and memory T lymphocytes, based on cytokine synthesis.
Blood samples were obtained from 44 healthy beagles that were divided into three age-groups: young (<4 years), middle-aged (4-8 years), and older dogs (>8 years). Subpopulations of T lymphocytes were determined by flow cytometry. Transcriptional (mRNA) levels of cytokines were determined for primary-cultured leukocytes using quantitative real-time polymerase chain reaction.
There were negative correlations between dogs' ages and the number of peripheral blood mononuclear cells, T cells, and B cells. In particular, the number of naive CD4 CD45RA T cells and CD8 CD45RA T cells significantly decreased with age. The mRNA levels for interleukin (IL)-2, IL-2Rα, and interferon-gamma were significantly higher in young or middle-aged dogs ( < 0.05), whereas IL-4 mRNA expression was not significantly different over the different age-groups. IL-2Rγ mRNA expression tended to decrease with age.
Decreases of naive CD4 and naive CD8 T cells may be related to age-related immunosenescence in dogs. With regard to cytokine production, leukocyte IL-4 and IL-10 mRNA levels did not change with age, whereas IL-2, IL-2Rα, and IL-2Rγ mRNA levels decreased with age. These altered cytokine mRNA expression patterns may contribute to decreased naive T-cell function(s) with aging.
免疫系统被认为会受到衰老的影响，而衰老与多种免疫发病机制相关。本研究的目的是基于细胞因子合成，确定健康犬（比格犬）免疫功能与年龄相关的变化，特别是初始和记忆T淋巴细胞的变化。
从44只健康比格犬采集血样，这些犬被分为三个年龄组：年轻组（<4岁）、中年组（4 - 8岁）和老年组（>8岁）。通过流式细胞术确定T淋巴细胞亚群。使用定量实时聚合酶链反应测定原代培养白细胞中细胞因子的转录（mRNA）水平。
犬的年龄与外周血单核细胞、T细胞和B细胞数量呈负相关。特别是，初始CD4 CD45RA T细胞和CD8 CD45RA T细胞的数量随年龄显著减少。白细胞介素（IL）-2、IL-2Rα和干扰素-γ的mRNA水平在年轻或中年犬中显著更高（<0.05），而IL-4 mRNA表达在不同年龄组之间无显著差异。IL-2Rγ mRNA表达倾向于随年龄降低。
初始CD4和初始CD8 T细胞的减少可能与犬的年龄相关免疫衰老有关。关于细胞因子产生，白细胞IL-4和IL-10 mRNA水平不随年龄变化，而IL-2、IL-2Rα和IL-2Rγ mRNA水平随年龄降低。这些细胞因子mRNA表达模式的改变可能导致衰老过程中初始T细胞功能下降。
