Fcγ receptor-mediated phagocytosis pathway was involved in phagocytosis of mIgNA+ B lymphocytes from largemouth bass (Micropterus salmoides)

作者：Wu, Jing; Nie, Yifan; Wang, Jingya; Feng, Guoqing; Hao, Le; Ma, Yanping; Li, Yugu^*; Liu, Zhenxing^*

来源：Journal of Fish Biology, 2023, 102(1): 128-140.

DOI：10.1111/jfb.15246

• Fc gamma receptor-mediated phagocytosis
• innate immunology
• Micropterus solmoides
• mIgM(+) B lymphocytes
• mRNA-seq

The potential for phagocytosis has been proven in teleost B cells, but the research on the regulatory mechanism of phagocytosis remains lacking. In this study, three largemouth bass (Micropterus salmoides) (15 +/- 5 g) were injected intraperitoneally with Nocardia seriolae (10(5) CFU/100 mu l/fish) in vivo, and their spleen was collected at 72 h post-infection for mRNA-seq. After the de novo assembly of the paired-end reads, 73,622 unigenes were obtained. Gene expression profiling revealed that 2043 unigenes were differentially expressed after N. seriolae infection, comprising 1285 upregulated and 758 downregulated unigenes (q-value <0.05, log2FC > vertical bar 2 vertical bar) of which 181 genes were involved in phagocytosis. The Kyoto Encyclopaedia of Genes and Genomes (KEGG) analysis demonstrated that 12 differentially expressed genes (DEG) associated with phagocytosis were enriched in the Fc gamma receptor-mediated phagocytosis signalling pathway. In vitro, the phagocytic ability of mIgM(+) B lymphocytes was validated using indirect immunofluorescence assay (IIFA) and fluorescence activating cell sorter (FACS), and the phagocytosis rates of the mIgM(+) B lymphocytes incubated with a Lyn inhibitor had decreased from 18.533 +/- 6.00% to 11.610 +/- 4.236% compared with the unblocked group. These results suggested that the Fc gamma receptor-mediated phagocytosis signalling pathway had participated in the phagocytosis of B cells and provide further insight into the role of B cells in innate immunology.

• 单位
  广东省农业科学院; 华南农业大学