Schultz Jonathan H, Adema Coen M
Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA.
Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA.
Dev Comp Immunol. 2017 Oct;75:3-15. doi: 10.1016/j.dci.2017.03.013. Epub 2017 Mar 18.
Comparative immunology, studying both vertebrates and invertebrates, provided the earliest descriptions of phagocytosis as a general immune mechanism. However, the large scale of animal diversity challenges all-inclusive investigations and the field of immunology has developed by mostly emphasizing study of a few vertebrate species. In addressing the lack of comprehensive understanding of animal immunity, especially that of invertebrates, comparative immunology helps toward management of invertebrates that are food sources, agricultural pests, pathogens, or transmit diseases, and helps interpret the evolution of animal immunity. Initial studies showed that the Mollusca (second largest animal phylum), and invertebrates in general, possess innate defenses but lack the lymphocytic immune system that characterizes vertebrate immunology. Recognizing the reality of both common and taxon-specific immune features, and applying up-to-date cell and molecular research capabilities, in-depth studies of a select number of bivalve and gastropod species continue to reveal novel aspects of molluscan immunity. The genomics era heralded a new stage of comparative immunology; large-scale efforts yielded an initial set of full molluscan genome sequences that is available for analyses of full complements of immune genes and regulatory sequences. Next-generation sequencing (NGS), due to lower cost and effort required, allows individual researchers to generate large sequence datasets for growing numbers of molluscs. RNAseq provides expression profiles that enable discovery of immune genes and genome sequences reveal distribution and diversity of immune factors across molluscan phylogeny. Although computational de novo sequence assembly will benefit from continued development and automated annotation may require some experimental validation, NGS is a powerful tool for comparative immunology, especially increasing coverage of the extensive molluscan diversity. To date, immunogenomics revealed new levels of complexity of molluscan defense by indicating sequence heterogeneity in individual snails and bivalves, and members of expanded immune gene families are expressed differentially to generate pathogen-specific defense responses.
比较免疫学研究脊椎动物和无脊椎动物，最早将吞噬作用描述为一种普遍的免疫机制。然而，动物多样性的规模巨大，给全面研究带来了挑战，免疫学领域的发展主要侧重于对少数脊椎动物物种的研究。在解决对动物免疫缺乏全面了解的问题时，尤其是对无脊椎动物免疫的了解，比较免疫学有助于管理作为食物来源、农业害虫、病原体或疾病传播媒介的无脊椎动物，并有助于解释动物免疫的进化。初步研究表明，软体动物门（第二大动物门）以及一般的无脊椎动物具有先天性防御，但缺乏脊椎动物免疫学所特有的淋巴细胞免疫系统。认识到共同免疫特征和特定分类群免疫特征的现实，并应用最新的细胞和分子研究能力，对选定的双壳类和腹足类物种进行深入研究，不断揭示软体动物免疫的新方面。基因组学时代迎来了比较免疫学的新阶段；大规模的努力产生了首批完整的软体动物基因组序列，可用于分析免疫基因和调控序列的完整互补序列。由于成本较低且所需工作量较小，新一代测序（NGS）使个体研究人员能够为越来越多的软体动物生成大量序列数据集。RNA测序提供表达谱，有助于发现免疫基因，而基因组序列揭示了免疫因子在软体动物系统发育中的分布和多样性。尽管从头计算序列组装将受益于持续发展，自动注释可能需要一些实验验证，但NGS是比较免疫学的强大工具，尤其有助于增加对广泛的软体动物多样性的覆盖。迄今为止，免疫基因组学通过指出单个蜗牛和双壳类动物中的序列异质性，揭示了软体动物防御的新复杂程度，并且扩展免疫基因家族的成员差异表达以产生针对病原体的特异性防御反应。
