Larazotide vs Thymosin Alpha-1

Immune

Immune

Research Only

Research Only

Larazotide is proposed to act on the zonulin/tight-junction signaling pathway, interrupting the gliadin-triggered cascade: gliadin exposure leads to zonulin release, which signals (via proposed EGFR/PAR2 pathways) on intestinal epithelium, causing downstream phosphorylation and disassembly of tight-junction proteins (claudins, occludin, ZO-1) and actin/myosin cytoskeletal rearrangement, resulting in increased paracellular permeability. Larazotide is reported to block this pathway upstream of tight-junction opening, preserving barrier integrity locally in the gut lumen. It is not systemically absorbed; in a Phase 1 study, plasma larazotide concentrations were below the assay limit of detection at all timepoints across oral doses up to 36 mg, consistent with local luminal action rather than systemic exposure.

Tα1 acts primarily on dendritic cells and T-cells via Toll-like receptor signaling — TLR9-MyD88-IRF7 driving type I interferon, and TLR2-MyD88-NF-κB driving IL-12, TNF-α, and IL-6. It promotes dendritic cell maturation, T-cell differentiation and thymic output, enhances NK cell cytotoxicity, upregulates MHC class I expression, and induces indoleamine 2,3-dioxygenase (IDO) to balance inflammation with tolerance. Unlike broad cytokine stimulators, Tα1 is a context-dependent immunomodulator that can enhance deficient responses and restrain overactive ones.

Approximately 2 hours after SubQ administration