摘要：Immunoglobulins (Igs) are essential defending molecules in jawed vertebrates, playing significant roles in humoral and mucosal immunity in a specific and adaptive manner. Initially, Igs have only been well investigated in humans and mice. However, over the past two decades, comparative studies of Igs in animals other than humans and mice have uncovered knowledges that are remarkably different from what we have known of human or mouse Igs with regard to their structure, functions and diversity generating mechanism. These significant findings, on one hand, reflect the diversity of immune system in different species, and on the other hand, are highly possible to be used to develop new agents or methods in many fields including basic research, biomedicine or agriculture.