Flu

Biography

Biography: Zheng Li

Abstract

Recent studies have elucidated that expression of certain glycoproteins in human saliva are increased or decreased according to age, meanwhile, human saliva may inhibit viral infection and prevent viral transmission. We find that seven lectins (e.g., MAL-II and SNA) show significant age differences among children, adults, and elderly individuals. Interestingly, we observe that healthy elderly individuals have the strongest resistance to influenza A virus mainly by presenting more terminal α2-3/6-linked sialic acid residues in their saliva, which bind with the influenza viral hemagglutinations. However, it is often noted that hospitalizations and deaths after an influenza infection mainly occur in the elderly population living with chronic diseases, such as diabetes and cancer. We find that the expression level of the terminal α2-3-linked sialic acids of elderly individuals with type 2 diabetes mellitus and liver disease are down-regulated significantly, and the terminal α2-6 linked sialic acids are up-regulated slightly or had no significant alteration. But, in the saliva of patients with gastric cancer, neither sialic acid is significantly altered. These findings may reveal that elderly individuals with chronic diseases, such as diabetes and liver disease, might be more susceptible to the avian influenza virus due to the decreased expression of terminal α2-3-linked sialic acids in their saliva.Our findings imply that the expression level of terminal α2-3 or α2-6-linked sialic acids in human saliva is a risk factor that could be a biomarker to distinguish those patients who are at a greater risk for infection with the avian or human influenza viruses.