Expression analysis of Igs and mucosal immune responses upon SVCV infection in common carp (Cyprinus carpio L.)

Sha Wu; Kaifeng Meng; Zhengben Wu; Ruhan Sun; Guangkun Han; Dacheng Qin; Yang He; Chuanjie Qin; Ping Deng; Jiafeng Cao; Wei Ji; Liqiang Zhang; Zhen Xu

doi:10.1016/j.fsirep.2021.100048

Expression analysis of Igs and mucosal immune responses upon SVCV infection in common carp (Cyprinus carpio L.)

Fish Shellfish Immunol Rep. 2021 Dec 24:3:100048. doi: 10.1016/j.fsirep.2021.100048. eCollection 2022 Dec.

Authors

Sha Wu¹, Kaifeng Meng¹, Zhengben Wu¹, Ruhan Sun¹, Guangkun Han¹, Dacheng Qin¹, Yang He², Chuanjie Qin², Ping Deng³, Jiafeng Cao¹, Wei Ji¹, Liqiang Zhang³, Zhen Xu⁴

Affiliations

¹ Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei 430070 China.
² Key Laboratory of Sichuan Province for Conservation and Utilization of Fishes resources in the Upper Reaches of the Yangtze River, Neijiang Normal University, Neijiang, Sichuan 641100, China.
³ Wuhan Academy of Agricultural Sciences, Wuhan, Hubei 430207, China.
⁴ State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China.

Abstract

The immunoglobulin (Ig) is a crucial component of adaptive immune system in vertebrates including teleost fish. Here complete cDNA sequence of IgD heavy chain gene from common carp (Cyprinus carpio) was cloned and analyzed. The full-length cDNA of IgD heavy chain gene contained an open reading frame (ORF) of 2460 bp encoding 813 amino acids. According to amino acids sequence, multiple alignment and phylogenetic analysis showed that carp Igs are closely related to those of Cyprinidae fish. Transcriptional expression of IgD as well as IgM, IgZ1 and IgZ2 showed similar expression patterns in different organs, this is, high expression level in systemic immune tissues (ie, head kidney, heart and spleen) and low expression in mucosal tissues (ie, gill, skin and gut). Following viral infection with spring viraemia of carp virus (SVCV), obvious pathological changes in skin, gill and gut mucosa and up-regulated expression of antiviral related genes in skin, gill, gut and spleen were observed, indicating that SVCV successfully infected common carp and activated the systemic and mucosal immune system. Interestingly, IgM showed a significant up-regulation only in systemic tissue (spleen), but not in mucosal tissues (gut, gills and skin), while increased expression of IgZ1 and IgZ2 was found in gut. In contrast, the expression of IgD increased significantly in spleen, gills and skin. These strongly suggest that fish Ig isotypes play different roles in mucosal and systemic immunity during viral infection. Common carp (Cyprinus carpio); Igs; Spring viraemia of carp virus (SVCV).