In the March issue of Immunity, Zajonc, Wilson, and their colleagues describe the crystal structure of a CD1a lipopeptide complex, which illustrates how peptide sequences can be presented to and recognized by T cells. The cover shows CD1a+ monocyte-derived dendritic cells (red) infected with M. tuberculosis expressing green fluorescent protein. During intracellular infection, M. tuberculosis produced dideoxymycobactin lipopeptides that trigger a T cell response mediated by CD1a presentation (ribbon diagram). Immunofluorescence images contributed by Carme Roura-Mir from the Branch Moody lab, and Immunity cover image courtesy of Cell Press.