Role of mucosal IgA antibodies as novel therapies to enhance mucosal barriers.

To prevent infection, the experience of the recent severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) pandemic has led to recognition of the importance of not only vaccines but also the strengthening of mucosal barriers by secretory immunoglobulin A (IgA). Strong mucosal barrier provided by IgA is also possible to prevent allergies and chronic inflammatory conditions in the intestinal tract, since it can protect foreign enemies or antigens at the first line of defense before their invasion. Therefore, it is important to understand the role of IgA antibodies secreted by the mucosa of the body. In this section, we discuss the role of mucosal IgA antibodies in relation to three disease states: control of intestinal microbiota, protection against infection, and allergy. In addition, we provide the evidence in which the quality as well as the quantity of IgA is critical for disease prevention. Therefore, we discuss about novel strategies to enhance mucosal barriers by induction of high-quality IgA.