Mucosal immunity in mollusks

The growing economical importance of mollusks has been associated with an increased awareness of, and attention to, infectious diseases affecting these animals. Of great concern is the fact that most studies on molluscan immunity focus on the circulating hemocytes and the humoral defense factors in the plasma while most relevant host-microbe interactions occur at mucosal interfaces. Mucus is produced from virtually all molluscan epithelia and plays an essential role in functions as diverse as lubrication, feeding, protection from environmental stress, and physical and biological barrier to infections. This chapter summarizes information available on the characteristics of mucosal tissues and mucus secretions in mollusks and on the their role in host-microbe interactions and overall animal health. Overall, current data underline the diversity and the dynamic nature of immune effectors associated with molluscan mucosal interfaces.