Antigen-specific CD4+ T cell response analysis

These experiments were performed as previously described [14 (link),15 (link)] with slight modifications. Briefly, mice received intravenous (i.v.) transfer of CFSE-labeled, congenically marked 5×10⁵ TEα cells 1 day before or 13 days after the intradermal exposure to mRNA(eGFP)-LNP or PBS. One μg of anti-Langerin-Eα or PBS were administered i.v. on day 14. Mice were then sacrificed 4 days later and the skin draining lymph nodes (axillary and brachial) harvested. Single-cell suspensions were stained with fixable viability dye (Thermo Fisher), CD4 (GK1.5), and CD90.1 (OX-7). The antibodies were purchased from BioLegend.