ALTERATIONS IN CELL-SURFACE CARBOHYDRATES ON T-CELLS FROM VIRALLY INFECTED MICE CAN DISTINGUISH EFFECTOR MEMORY CD8(+) T-CELLS FROM NAIVE CELLS/

Glycosylation changes on surface molecules of T cells affect cell traf ficking and function and may be useful in discriminating between naive , effector, and memory T cells, To analyze oligosaccharide structures on T cells activated in vivo, we examined alterations in sialic acid r esidues on T cells following infection of mice with lymphocytic chorio meningitis (LCMV), vaccinia virus, and vesicular stomatitis virus, We found that the majority of CD8 T cells from mice acutely infected with these viruses showed increased binding to peanut agglutinin (PNA), Al l of the PNA(high)CD8 T cells from infected mice were CD44(high), indi cating that glycosylation changes were occurring on activated T cells, There was also an increase in the PNA(high)CD4 T cell population in v irally infected mice, Increased PNA binding to activated CD8 T cells c orrelated with higher endogenous neuraminidase levels in these cells, This higher neuraminidase activity most likely contributed to the PNA( high) phenotype by cleaving sialic acid residues off the core-1 O-glyc ans or glycoproteins destined for the cell surface. A PNA(high)CD8 T c ell population persisted in immune mice that had cleared the LCMV infe ction, When spleen cells from immune mice were sorted into PNA(high) a nd PNA(low) populations, >95% of the LCMV-specific memory CD8 T cells segregated with the PNA(high) population. This shows that virus-specif ic memory CD8 T cells remain hyposialylated and can be distinguished f rom naive CD8 T cells based on PNA binding, Thus, PNA can be used as a marker for Ag-experienced T cells.