Enhancement of CD8 T-cell function through modifying surface glycoproteins in young and old mice.

Previous work from our laboratory has shown that modifying cell surface glycosylation with either a Clostridium perfringens-derived sialidase (CP-Siase), or an O-linked glycoprotein endopeptidase (OSGE) can enhance the function of CD4 T cells from both young and old mice at multiple levels. Here we have re-assessed the effect of age on CD8 T-cell function, and examined the outcome of enzymatic treatment with CP-Siase and OSGE on its different aspects. Pre-treatment of CD8 T cells with either CP-Siase or OSGE led to a significant increase in anti-CD3-mediated Ca2+ response in both young and old mice. Pre-treated CD8 T cells from both age groups also displayed a significant increase in activation-induced CD69 and CD25 expression, and produced significantly higher amounts of interleukin-2 and interferon-gamma in comparison to their untreated counterparts. Furthermore, pretreatment with either enzyme enhanced granzyme B expression in CD8 T cells, and increased their cytolytic activity in vitro. These data support the notion that glycosylated surface proteins hinder CD8 T-cell activation and function in both young and old mice, and raise the possibility of significantly improving CD8 T cell function in older individuals through enzymatic alteration of surface glycoproteins.