biostudies-literatureMa ZYFundamental Research Funds for the Central UniversitiesNational Natural Science Foundation of ChinaNational Key Research and Development Program of China873982https://www.ebi.ac.uk/biostudies/studies/S-EPMC8977587biostudies-literatureUnknown13The complement system is an important part of the immune system of teleost fish. Besides, teleost B cells possess both phagocytic activity and adaptive humoral immune function, unlike mammalian B1 cells with phagocytic activity and B2 cells specific to adaptive humoral immunity. However, the cross talk between complement system and phagocytic B cells in teleost fish still requires elucidation. Here, we show that, unlike tetrapods with a single <i>C3</i> gene, nine <i>C3</i> genes were identified from the grass carp (<i>Ctenopharyngodon idella</i>) genome, named <i>C3.1</i>-<i>C3.9</i>. Expression analysis revealed that C3.1 is the dominant C3 molecule in grass carp, for its expression was significantly higher than that of the other C3 molecules both at the mRNA and protein levels. The C3a Frontiers in immunologyComplement C3a Enhances the Phagocytic Activity of B Cells Through C3aR in a Fish.PMC897758731972824, 316021842018YFD09005052662018QD053Li WSMa ZYLi JZhang XJHu YZZhang YALiang JXSun YWu CSfalseComplement C3a Enhances the Phagocytic Activity of B Cells Through C3aR in a Fish.The complement system is an important part of the immune system of teleost fish. Besides, teleost B cells possess both phagocytic activity and adaptive humoral immune function, unlike mammalian B1 cells with phagocytic activity and B2 cells specific to adaptive humoral immunity. However, the cross talk between complement system and phagocytic B cells in teleost fish still requires elucidation. Here, we show that, unlike tetrapods with a single <i>C3</i> gene, nine <i>C3</i> genes were identified from the grass carp (<i>Ctenopharyngodon idella</i>) genome, named <i>C3.1</i>-<i>C3.9</i>. Expression analysis revealed that C3.1 is the dominant C3 molecule in grass carp, for its expression was significantly higher than that of the other C3 molecules both at the mRNA and protein levels. The C3a 2022-01-01T00:00:00Z20222026-05-31T21:03:01.718Z2025-02-19T04:22:34.04ZS-EPMC89775873538670410.3389/fimmu.2022.873982