Figure 2.

PEGylated peptides efficiently activate antigen-specific CD4⁺ T cells in vivo. CFSE-labeled CD4⁺ T cells from DO11.10 mice were transferred into BALB/c mice. After 24 h recipients received i.v. PBS (control), indicated amounts of pOVA or equimolar amounts (based on peptide amount) of pOVA-PEG20, pOVA-PEG40 or pOVA-PEG-tetramer. 5 µg of pOVA are equivalent to 2.8 nM (and 250 µg/kg) per mouse. After 6 days, proliferation was assessed by flow cytometry (for representative dot plots, see Figure 4 ). Displayed is the mean x-fold CFSE dilution ± SD gated on OVA-TCR⁺ CD4⁺ splenocytes from at least two independent experiments. n = 4–6; PBS, n = 10.