Gasdermin D limits inflammasome-dependent control of Toxoplasma gondii

Inflammasome activation is a central component of host defense against Toxoplasma gondii, yet the contribution of downstream plasma membrane damage pathways to protective immunity remains unclear. Here, we show that infection of primary macrophages with virulent type I T. gondii induces rapid NLRP3 inflammasome activation, leading to IL-1β release, membrane permeabilization, and cell death. Unexpectedly, although caspase-1/11 was required for parasite control, the pore-forming effector gasdermin D (GSDMD) limited host resistance. GSDMD-deficient macrophages and mice exhibited enhanced control of parasite replication, despite reduced cell death. Mechanistically, GSDMD deficiency resulted in increased early IL-1β release. Exogenous IL-1β restored parasite control in wild-type macrophages, indicating that early cytokine availability is a key determinant of resistance. Enhanced control in GSDMD-deficient cells was associated with increased NLRP3 inflammasome assembly and was partially reversed by pharmacological inhibition of NLRP3, supporting a role for early inflammasome signaling in parasite restriction. In contrast, NINJ1-deficient macrophages displayed impaired IL-1β release and increased parasite replication, indicating that GSDMD and NINJ1 play non-redundant roles during T. gondii infection. Pharmacological inhibition of GSDMD using disulfiram recapitulated the protective phenotype in both murine and human macrophages and reduced parasite burden in vivo, demonstrating that targeting GSDMD may represent a therapeutic strategy to enhance host control of intracellular pathogens. Together, these findings challenge the canonical view of the caspase-1-GSDMD axis as a linear pathway, demonstrating that these effectors instead exert opposing functions during T. gondii infection, with caspase-1 promoting host resistance while GSDMD counteracts it.