Healthy human donors have preexisting immunity to the rAls3p-N vaccine protein. A, Serum samples from 13 donors were tested in immunoglobulin (Ig) G, IgG1, IgG2, IgG3, and IgG4 enzyme-linked immunosorbent assays to quantify rAls3p-N titers. Bars denote median titers. B, Peripheral blood mononuclear cells (PBMCs) from healthy human donors produce interferon (IFN)–γ and interleukin (IL)–17 in response to the rAls3p-N protein and to pre-germinated, heat-killed Candida albicans. Results from 14 donors are shown in both graphs. Spots from each well were normalized per 105 PBMCs. Bars denote median values. *P <.05 versus media; **P <.05 versus both rAls3p-N and media. C, Supernatants from 6 donor PBMCs were assayed for cytokines by Cytometric Bead Array. Bars denote median values. *P <.05 versus media control.