The sea cucumber Apostichopus japonicus is one of the most valuable sea food in East Asian countries due to its superior nutritive and medicinal properties. However, various diseases in A. japonicus aquaculture caused by bacteria, viruses, and protozoa were frequently observed, limiting the development of this industry. The immune competence of host appears to be determined by both genetics and environmental factors, including gender, age, and diet. However, the comprehensive difference in immunity between female and male A. japonicus is still not clear.