Cysteine Reactivity Profiling Identifies Host Regulators of <i>Mycobacterium tuberculosis</i> Replication in Human Macrophages

Innate immune cells, such as monocytes and macrophages, provide the earliest defense against intracellular pathogen infection by initiating signaling pathways and restricting pathogen replication. However, the full complement of proteins that mediate cell-autonomous immunity remains incompletely defined. Here, we applied cysteine-directed activity-based protein profiling (ABPP) to map proteome-wide cysteine reactivity changes in THP-1 monocytes and primary human monocyte-derived macrophages during <i>Mycobacterium tuberculosis</i> (Mtb) infection. Across both cell types, we quantified 148 cysteine residues with altered reactivity. Knockdown of a subset of proteins harboring infection-induced reactivity significantly altered Mtb replication in THP-1 monocytes, linking proteins with reactive cysteines to antimicrobial defense. These data define previously unrecognized host protein changes during Mtb infection and provide a resource for investigating post-translational events that regulate innate immune responses to intracellular bacteria.