Diversity and multiple functions of lectins in shrimp immunity

Lectins play important roles in many biological processes, including protein trafficking, cell signaling, pathogen recognition, as effector molecules, and so on, because of their capacity to bind carbohydrates. Presently, seven groups of lectins have been identified in shrimp: C-type, L-type, P-type, M-type, fibrinogen-like domain lectins, galectins, and calnexin/calreticulin. These lectins have different structures, diverse expression patterns, and multiple functions in the shrimp immune response. This review summarizes the research progress and analyzes the diversity of shrimp lectins, focusing mainly on the C-type lectin family. Shrimp C-type lectins show considerable diversity in their domain architectures, sugar substrates, tissue distributions, expression patterns responding to pathogen challenge and functions in shrimp immunity.