MYD88 and viral infectious disease: Since one of the hallmarks of mucosal immunity is the production of secretory IgA, which acts to prevent bacterial and viral infection, and since CTB is capable of inducing specific IgA [47–51] by synergism with MyD88-dependent TLR signals which selectively imprint a IgA-inducing capacity in nonmucosal DCs [52], we studied this immunoglobulin in CTB-Fim2-immunized mice and verified that mice administered CTB-Fim2 elicited specific Fim2-IgA in BAL.