Medical Mycology Unit, Department of Biology, National Institute for Cellular Biotechnology, National University of Ireland, Maynooth, Ireland.
Virulence. 2011 Sep-Oct;2(5):413-21. doi: 10.4161/viru.2.5.17811. Epub 2011 Sep 1.
Larvae of Galleria mellonella are useful models for studying the virulence of microbial pathogens or for evaluating the potency of antimicrobial agents. In this work we demonstrated that prior exposure of larvae to non-lethal doses of Aspergillus fumigatus conidia increases the resistance of larvae to a lethal dose (1 x 10⁷ 20 μl⁻¹) 24 h later. Exposure of larvae to a conidia concentration of 1 x 10⁴ 20 μl⁻¹ leads to an increase in haemocyte density but an inoculum of 1 x 10⁵ conidia leads to enhanced expression of antimicrobial peptides, increased binding of proteins (e.g. arylophorin, prophenoloxidase, apolipophorin ) to conidia and elevated hemocytes density. These results suggest that a low dose of conidia (1 x 10⁴) predominantly activates the cellular immune response but that a higher dose (1 x 10⁵) that is still not lethal activates a humoral immune response to the greatest extent. While insects have an immune system analogous to the innate immune response of mammals these results suggest that it is capable of assessing the extent of the microbial challenge and mounting a "proportionate" immune response, which may have important survival advantages.
家蚕幼虫是研究微生物病原体毒力或评估抗菌剂效力的有用模型。在这项工作中，我们证明了幼虫在接触非致死剂量的烟曲霉分生孢子后，24 小时后对致死剂量（1×10⁷20 μl⁻¹）的抵抗力增加。幼虫暴露于 1×10⁴个分生孢子/20 μl 的浓度下会导致血球密度增加，但接种 1×10⁵个分生孢子会导致抗菌肽表达增强，蛋白质（如芳基磷蛋白、原酚氧化酶、载脂蛋白）与分生孢子的结合增加，血球密度升高。这些结果表明，低剂量的分生孢子（1×10⁴）主要激活细胞免疫反应，但仍未致死的更高剂量（1×10⁵）最大限度地激活了体液免疫反应。尽管昆虫的免疫系统类似于哺乳动物的先天免疫反应，但这些结果表明，它能够评估微生物挑战的程度，并产生“相称”的免疫反应，这可能具有重要的生存优势。
