Polish Academy of Sciences, Witold Stefański Institute of Parasitology, Warsaw, Poland.
BIOMIBO, Warsaw, Poland.
PLoS One. 2020 Feb 6;15(2):e0228556. doi: 10.1371/journal.pone.0228556. eCollection 2020.
Invertebrates are becoming more popular models for research on the immune system. The innate immunity possessed by insects shows both structural and functional similarity to the resistance displayed by mammals, and many processes occurring in insect hemocytes are similar to those that occur in mammals. The humoral immune response in insects acts by melanization, clotting and the production of reactive oxygen species and antimicrobial peptides, while the cellular immunity system is based on nodulation, encapsulation and phagocytosis. An increasingly popular insect model in biological research is Galleria mellonella, whose larvae are sensitive to infection by the entomopathogenic fungus Conidiobolus coronatus, which can also be dangerous to humans. One group of factors that modulate the response of the immune system during infection in mammals are heat shock proteins (HSPs). The aim of this study was to investigate whether infection by C. coronatus in G. mellonella hemolymph is accompanied by an increase of HSP90, HSP70, HSP60 and HSP27. Larvae (five-day-old last instar) were exposed for 24 hours to fully-grown and sporulating fungus. Hemolymph was collected either immediately after termination of exposure (F24) or 24 hours later (F48). The concentration of the HSPs in hemolymph was determined using ELISA. Immunolocalization in hemocytes was performed using fluorescence microscopy and flow cytometry. HSP90, HSP70, HSP60 and HSP27 were found to be present in the G. mellonella hemocytes. HSP60 and HSP90 predominated in healthy insects, with HSP70 and HSP27 being found in trace amounts; HSP60 and HSP27 were elevated in F24 and F48, and HSP90 was elevated in F48. The fungal infection had no effect on HSP70 levels. These findings shed light on the mechanisms underlying the interaction between the innate insect immune response and entomopathogen infection. The results of this innovative study may have a considerable impact on research concerning innate immunology and insect physiology.
无脊椎动物正成为研究免疫系统的热门模型。昆虫所具有的先天免疫在结构和功能上与哺乳动物的抵抗力相似，昆虫血细胞中发生的许多过程与哺乳动物中发生的过程相似。昆虫的体液免疫反应通过黑化、凝结和产生活性氧和抗菌肽来发挥作用，而细胞免疫系统则基于结节、包裹和吞噬作用。在生物研究中，越来越受欢迎的昆虫模型是家蚕，其幼虫容易感染昆虫病原真菌球孢白僵菌，而该真菌对人类也可能有危险。在哺乳动物感染过程中调节免疫系统反应的一组因素是热休克蛋白 (HSP)。本研究的目的是研究家蚕血淋巴中感染球孢白僵菌是否伴随着 HSP90、HSP70、HSP60 和 HSP27 的增加。幼虫（五龄末）暴露于完全生长和产孢真菌中 24 小时。暴露结束后立即（F24）或 24 小时后（F48）收集血淋巴。使用 ELISA 测定血淋巴中 HSP 的浓度。使用荧光显微镜和流式细胞术在家蚕血细胞中进行免疫定位。在家蚕血细胞中发现 HSP90、HSP70、HSP60 和 HSP27。在健康昆虫中 HSP60 和 HSP90 占主导地位，痕量存在 HSP70 和 HSP27；在 F24 和 F48 中 HSP60 和 HSP27 升高，而在 F48 中 HSP90 升高。真菌感染对 HSP70 水平没有影响。这些发现揭示了先天昆虫免疫反应与昆虫病原感染之间相互作用的机制。这项创新研究的结果可能对先天免疫学和昆虫生理学的研究产生重大影响。
