The role of lysozyme and complement in the antibacterial activity of zebrafish (Danio rerio) egg cytosol

Most fish embryos develop in an aquatic environment full of potential pathogens. How fish embryos survive pathogenic attacks before the maturation of their own immunocompetence remains poorly understood. Here we demonstrated that bacteriolytic mechanism contributed to the antibacterial activity of zebrafish egg cytosol. In addition, the maternal lysozyme in the egg cytosol plays a key role in the bacteriolytic activity of the zebrafish eggs, which can be significantly stimulated by the cooperation with complement. This is the first report providing the evidence for the functional role of the maternal lysozyme and its cooperation with complement in fish eggs.