Cross-protective TH1 immunity against Aspergillus fumigatus and Candida albicans

T cell-mediated heterologous immunity to different pathogens is promising for the development of immunotherapeutic strategies. Aspergillus fumigatus and Candida albicans, the 2 most common fungal pathogens causing severe infections in immunocompromised patients, are controlled by CD4+ type 1 helper T (T(H)1) cells in humans and mice, making induction of fungus-specific CD4+ T(H)1 immunity an appealing strategy for antifungal therapy. We identified an immunogenic epitope of the A fumigatus cell wall glucanase Crf1 that can be presented by 3 common major histocompatibility complex class II alleles and that induces memory CD4+ T(H)1 cells with a diverse T-cell receptor repertoire that is cross-reactive to C albicans. In BALB/c mice, the Crf1 protein also elicits cross-protection against lethal infection with C albicans that is mediated by the same epitope as in humans. These data illustrate the existence of T cell-based cross-protection for the 2 distantly related clinically relevant fungal pathogens that may foster the development of immunotherapeutic strategies.