Page 44 - 《水产学报》2025年第6期

雷丽娜，等 水产学报, 2025, 49(6): 069403

Molecular cloning and expression analysis of IgMH and MHCⅡβ genes in
the spotted sea bass (Lateolabrax maculatus)

1,2
3
1,2*
1,2
1,2
LEI Lina , GAO Qian , WANG Wei , SUN Zhaosheng , LUO Zhang , LIU Qigen 1,2
1. Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education,
Shanghai Ocean University, Shanghai 201306, China;
2. International Research Center for Marine Biosciences, Ministry of Science and Technology,
Shanghai Ocean University, Shanghai 201306, China;
3. Tianjin Key Lab of Aqua-ecology and Aquaculture, College of Fisheries,
Tianjin Agricultural University, Tianjin 300384, China

Abstract: To gain a deeper comprehension of the adaptive immune mechanism involved in disease prevention and control of
Lateolabrax maculatus, this study employed RT-PCR and RACE techniques to clone the immunoglobulin M heavy chain
(IgMH) and Major histocompatibility compatibility complex β (MHCⅡ β). Additionally, real-time fluorescence quantitative
PCR (qPCR) was utilized to examine the expression distribution in different tissues of spotted sea bass, along with the altera-
tions in mRNA levels following LPS, Poly (I: C) stimulation, and Edwardia tarda infection. Finally, the expression of recom-
binant proteins IgMH, IgMCH 1-2 , and MHCⅡ β was achieved by constructing prokaryotic recombinant expression plasmids
IgMH-pET21d, IgMCH 1-2 -pET21d, and MHCⅡ β-PET21d. The proteins were obtained through molecular sieve chromato-
graphy, and anti IgMH Polyclonal antibodies of L. maculatus were successfully prepared. The results indicated that the full
length cDNA of IgMH and MHCⅡ β in L. maculatus were 1 977 bp and 1 242 bp, respectively. The genes IgMH and MHCⅡ β
exhibit high expression in immune-related tissues, including gills, spleen, and head kidney. LPS and Poly (I:C) stimulation and
delayed Edwardsiella artificially infected L. maculatus led to significant changes in the expression levels of these two genes in
gill, spleen and head and kidney, indicating that both IgMH and MHCⅡ β participated in the anti-infection immune response of
L. maculatus. Additionally, immunoblotting analysis demonstrated that anti-IgM Polyclonal antibodies display strong reactiv-
ity with the entire serum of L. maculatus, weak reactivity with Siniperca chuatsi, and no reactivity with Micropterus salmoides
and Cienoyharyngodoni della. It is speculated that the reaction intensity reflects the genetic relationship between species. In
summary, this study successfully accomplished the cloning of the complete sequences of IgMH and MHCⅡ β genes, followed
by the expression of recombinant IgMH and MHCⅡ β proteins. Additionally, the production of Anti-IgM polyclonal antibody
was achieved. The findings of this study provided evidence supporting the involvement of IgMH and MHCⅡ β in the immune
response of L. maculatus. Furthermore, these results established a solid groundwork for future investigations on immune regula-
tion and disease prevention and control strategies for L. maculatus.
Key words: Lateolabrax maculatus; IgMH; MHCⅡ β; expression regulation; protein purification
Corresponding author: GAO Qian. E-mail: qgao@shou.edu.cn
Funding projects: National Key Research and Development Program of China (2018YFD0900605)

https://www.china-fishery.cn 中国水产学会主办 sponsored by China Society of Fisheries
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