Abstract
Invasive candidiasis, primarily caused by Candida albicans, represents the most common fungal disease among hospitalized patients and poses a significant threat to human health. Intrinsic or acquired immunosuppression serves as a critical risk factor predisposing individuals to this disease, while simultaneously reducing the efficacy of conventional antifungal therapies and worsening clinical outcomes. Given the central role of immune dysfunction in the pathogenesis of invasive candidiasis, immunotherapeutic strategies hold substantial promise. We targeted dectin-1, the primary pattern recognition receptor for β-1,3-glucan, by engineering XJ104, a bispecific T-cell engager that fuses dectin-1 to the light chains of an anti-CD3 monoclonal antibody. This construct is designed to bridge Candida β-1,3-glucan with CD3 on T cells, thereby inducing anti-Candida immunity. Our results demonstrate that XJ104 exhibits high specificity for β-1,3-glucan and activates effector cells in a Candida-dependent manner in vitro. In murine models, XJ104 enhances Th1 and Th17 responses and confers significant protection against both C. albicans and non-albicans infections. Crucially, CD3+ T-cell depletion and cytokine neutralization abolished this protection, confirming the T-cell-dependent protective efficacy of XJ104. These results establish that enhancing the endogenous T-cell function represents an effective strategy against invasive candidiasis. In conclusion, our study presents a novel therapeutic approach that bridges T cells and Candida pathogens, promoting robust Candida-specific immunity and controlling invasive infections caused by Candida spp. These findings underscore the potential of XJ104 as a clinically promising immunotherapy for the treatment of invasive candidiasis.