Gut-mammary-sIgA axis and immunologic mechanisms induced by porcine epidemic diarrhea virus

Abstract:

Swine gut-mammary gland-sIgA (secretory IgA) axis is an immune route involving pregnant sows, which, once being infected or vaccinated by a gastroenteric route with an enteric pathogen can confer immune protection to their offspring against such pathogen through IgA contained in their colostrum or milk. The dynamic model of the axis is composed of complicated processes (e.g., invasion of pathogen, antigen presentation, activation of lymphocytes, homing of lymphocytes into intestine or mammary gland, and antibody secretion), which may be influenced or regulated by various factors such as virulence of pathogen, stage of pregnancy, and immune state of sow. The study about the axis model evoked by infection of porcine epidemic diarrhea virus (PEDV) can be used to explain the immune protection acquired through infection of virulent virus, while the design of vaccine and vaccination protocol depending on the model has not been satisfactory. This review summarized the studies about PEDV infection and host immune response and analyzed the key factors influencing the axis. it is suggested that more attention should be paid to functions of inactivated PEDV vaccine and specific IgG antibody though the immune axis, which is the most efficient mechanism for PEDV prevention.