Department of Entomology, University of Georgia, Athens, GA, USA.
Arch Insect Biochem Physiol. 2011 Apr;76(4):185-94. doi: 10.1002/arch.20394. Epub 2011 Jan 19.
Ecological immunity studies in invertebrates, particularly insects, have generated new insights into trade-offs between immune functions and other physiological parameters. These studies document physiologically directed reallocations of immune costs to other high-cost areas of physiology. Immunosenescence, recognized as the age-related deterioration of immune functions, is another mechanism of radically altering immune systems. We investigated the hypothesis that aging brings on immunosenescence in adult males of the cricket, Gryllus assimilis. Our data show that the intensity of melanotic nodule formation decreased with adult age from after 3-week post-adult emergence. Circulating hemocyte populations similarly decreased from about 5,000 hemocytes/µl hemolymph to about 1,000 hemocytes/µl hemolymph. The numbers of damaged hemocytes in circulation increased from less than 10% at 1-week post-adult emergence to approximately 60% by 3-week post-adult emergence. The composition of hemocyte types changed with age, with increasing proportions of granulocytes and decreasing proportions of plasmatocytes. The declines in nodule formation were not linked to the adult age of sexual behaviors, which begin shortly after entering adulthood in this species. We infer that age-related senescence, rather than cost reallocations, may account for observed declines in various parameters of immune functions in insects, as seen in other animals.
无脊椎动物，尤其是昆虫的生态免疫研究为免疫系统功能与其他生理参数之间的权衡关系提供了新的认识。这些研究记录了生理上的免疫成本再分配到其他高成本的生理领域。免疫衰老，即与年龄相关的免疫系统功能恶化，是另一种改变免疫系统的机制。我们研究了这样一个假设，即衰老会导致蟋蟀成年雄性个体的免疫衰老。我们的数据表明，黑色素结节形成的强度随着成年后出现后的第 3 周而逐渐降低。循环血细胞数量也从约 5000 个血细胞/µl 血液下降到约 1000 个血细胞/µl 血液。循环中受损血细胞的数量从成年后出现后第 1 周的不到 10%增加到第 3 周的约 60%。血细胞类型的组成随年龄而变化，粒细胞的比例增加，浆细胞的比例减少。结节形成的下降与性行为的成年年龄无关，在该物种中，性行为在成年后不久就开始了。我们推断，与年龄相关的衰老，而不是成本再分配，可能是昆虫各种免疫功能参数下降的原因，就像在其他动物中看到的那样。
