CD19 and infection: As shown in Fig. 1A, despite the presumed broad cellular tropism of VV and related viruses, rMVA-GFP did not infect all subsets of splenocytes to an equivalent extent, but rather demonstrated a striking preference for professional APC populations, with CD11c+ DCs being the most susceptible targets for MVA infection in the spleen (31.2 ± 2.9% GFP+), followed by CD11b+ CD11c- macrophages (20.1 ± 2.8% GFP+) and CD19+ B cells (8.5 ± 2.1% GFP+).