Better protection by saliva as we age

Better protection by saliva as we age

from UCLA 

Recently studies discovered that important changes in saliva happen as we age. But first what is saliva. Saliva is a secretion found in the oral cavity. It is required for many things. It initiates digestion, helps maintain teeth, is necessary for oral homeostasis, and has antimicrobial properties. Saliva is approximately 94% water the rest is an interesting mix of molecules. Many of the minor constituents have biologic activity required for the roles that saliva plays.

One of the major changes recently discovered is that as we age the glycoproteins that are expressed change. One change is that older people express glycoproteins with more terminal alpha 2-3/6-linked sialic acid residues¹. These sialic acid residues bind the hemagglutinin(HA) on the surface of viral particles. This provides protection against influenza. Qin et. al.¹ showed that the binding of the virus particles to the glycoprotein increases  and that the composition of glycoproteins changes to a mixture that has more binding sites as we age. This shows that even though as we age our immune system declines in effectiveness we have other protective mechanisms that continue to protect and even improve in their effectiveness as we age. 

1. Yannan Qin, Yaogang Zhong, Minzhi Zhu, Liuyi Dang, Hanjie Yu, Zhuo Chen, Wentian Chen, Xiurong Wang, Hua Zhang, and Zheng Li Age- and Sex-Associated Differences in the Glycopatterns of Human Salivary Glycoproteins and Their Roles against Influenza A Virus
   Journal of Proteome Research 2013 12 (6), 2742-2754