SG-3-05429

SG-3-05429 is an investigational **microbiome-derived peptide** immuno-oncology agent from Second Genome. Publicly available preclinical disclosures indicate it emerged from optimization of the earlier peptide SG-3-0020, which was identified from *Bifidobacterium breve* proteins screened for T-cell activating activity. In vitro, the parent program increased effector cytokine secretion and PD-1 expression in activated human T cells, and SG-3-05429 was selected as the highest-potency engineered peptide for follow-up mechanistic work. The precise molecular target has not been publicly disclosed beyond description as a transmembrane glycoprotein of the immunoglobulin superfamily, so the exact target-level mechanism remains unclear. Available pipeline sources describe the asset as preclinical and being developed for neoplasms.