Abstract

Lv Blimp1 is identified as a key stress-responsive factor regulating macrophage-like phagocyte function in shrimp hemolymph. • Lv Blimp1 interacts with Lv Hes1 to form a transcriptional complex and coordinate antibacterial immunity. • Lv Blimp1 deficiency impairs shrimp phagocytosis and bacterial resistance, providing a vital target for disease-resistant breeding. B-lymphocyte-induced maturation protein 1 (Blimp1) is a highly conserved transcription factor that governs cell fate specification in metazoan. In this study, we identified Lv Blimp1 as a stress-responsive protein in shrimp hemolymph. Functional knockdown assays revealed that Lv Blimp1 silencing significantly impaired cellular immunity, as evidenced by reduced total hemocyte counts, decreased hemocyte viability and phagocytic efficiency, accompanied by elevated intracellular ROS levels and diminished lysozyme expression. Fluorescence activated cell sorter (FACS) analysis demonstrated that Lv Blimp1 is predominantly enriched in phagocytic hemocytes. Comparative transcriptomic profiling and qPCR validation further demonstrated that depletion of Lv Blimp1 downregulated the expression of key marker genes associated with shrimp macrophage-like phagocytes, including CHF , NPC2 , NLRP3 , Casp1 , zfh1 , and CHIT1 . Mechanistically, co-immunoprecipitation assays confirmed that Lv Hes1 physically interacts with Lv Blimp1 and is functionally associated with the regulation of a set of common immune genes. Functional ablation of either Lv Hes1 or Lv Blimp1 in shrimp hemocytes compromised host antibacterial defense. These two TFs synergistically regulated the expression of key genes including CIB1 and IMC1 . Taken together, our data indicate that Lv Blimp-1 and Lv Hes1 synergistically regulate shrimp macrophage-like phagocyte activity.