Treatment with pUL11Fc affects phosphorylation of the regulatory tyrosines of Lck.

PBMC were incubated with anti-CD3 (OKT3) in the presence or absence of UL11Fc and Fc at the indicated concentrations for three days. Cells were then labelled extracellularly with anti-CD3 and anti-CD4 and intracellularly with anti-Lck pY505 or anti-Lck pY394. The experiment was repeated three times using cells from different donors. Mean fluorescence intensities are shown for Y505 (i) and Y394 (ii) phosphorylation of live CD3+CD4+ cells, fold increases in geometric mean fluorescent intensity normalised to anti-CD3 treated cells are indicated. A) depicts one representative experiment (values for UL11 treated cells). B) shows fold increases in phosphorylation over all three experiments for UL11Fc and Fc treated cells. Error bars indicate standard deviation. Statistical significance of differences between groups was determined by ANOVA. i)*p = 0.0014 for the difference in Y505 phosphorylation between pUL11Fc and Fc treated cells. ii)*p = 0.0043 for the difference in Y394 phosphorylation between pUL11Fc and Fc treated cells.