Teleost fish IgM+ plasma-like cells possess IgM-secreting, phagocytic, and antigen-presenting capacities

作者：Liting Wu, Yanjian Yang, Along Gao, Jun Li, Jianmin Ye · 发表于：Frontiers in Immunology · 年份：2022 · DOI：10.3389/fimmu.2022.1016974 · 被引用次数：29 · 研究领域：Aquaculture disease management and microbiota、Invertebrate Immune Response Mechanisms、T-cell and B-cell Immunology

Plasma cells are terminally differentiated antibody-secreting B lymphocytes that contribute to humoral immunity by producing large numbers of antibodies. Increasing evidence suggests that teleost fish B cells share certain characteristics with mammalian B1 B cells, including antibody-secreting, phagocytic, and antigen-presenting capacities. However, the difference between mature B cells and plasma cells remains unclear. In this study, we found that, based on their light-scattering characteristics, tilapia anterior kidney (AK) leukocytes can be categorized into two IgM + B-cell subsets: the lymphoid (L) gate and granulocyte–monocyte/macrophage (G-M) subsets. G-M gate cells are more numerous than L-gate cells and have higher mean fluorescence, but lower forward scatter and side scatter. We analyzed the morphological and ultrastructural features of sorted IgM + cells and found that L-gate IgM + cells have a high nucleus–cytoplasm ratio and lymphocyte-like morphology, whereas G-M gate IgM + cells have a small nucleus, more abundant endoplasmic reticulum, and a larger number of mitochondria, and have a plasma cell-like or macrophage-like morphology. To further characterize the cell types, we examined the specific patterns of expression of B-cell- and T-cell-related genes. We found that B-cell-specific genes were expressed by both L-gate and G-M gate IgM + cells, and that G-M gate IgM + cells secreted extremely high levels of IgM. However, T-cell-related genes were highly expressed...