MUC5AC and infection: Such glycans can be further modified by processes such as fucosylation, sialylation and sulphation, which play a major role in the structure and function of the mucin.5, 7 It is clear that given such combinatorial variety, the glycans decorating any given mucin will vary in length, sequence and composition, which is key to their orchestration of the immune response to infection and their protection of the underlying epithelium against mechanical and chemical stress.10