A synthetic pentapeptide derived from splenic tissue that modulates immune function and enhances NK cell activity.
Splenopentin (SP-5) is a synthetic pentapeptide (Arg-Lys-Glu-Val-Tyr) originally identified in splenic tissue extracts. It represents the immunologically active portion of a larger spleen-derived peptide called splenin. The spleen plays a critical role in filtering blood, recycling iron, and housing immune cells — and spleen-derived peptides have been studied for their immunomodulatory properties.
Splenopentin enhances natural killer (NK) cell cytotoxicity, promotes T-cell proliferation, and modulates macrophage function. It appears to normalize immune responses — enhancing function when suppressed and moderating it when hyperactive — a hallmark of true immunomodulators versus simple immunostimulants.
Interest in splenopentin comes from the broader field of organ-specific bioregulatory peptides, alongside thymic peptides (thymosin alpha-1, thymulin) and pineal peptides (epithalon, pinealon).
Preclinical studies demonstrate splenopentin enhances NK cell activity by 30-50% in immunosuppressed models. It restores T-cell proliferative responses after chemotherapy or radiation-induced immunosuppression. In tumor models, splenopentin showed anti-tumor immune enhancement.
Clinical data is extremely limited. Most research originates from Eastern European and Russian institutions. The peptide is part of the Khavinson bioregulator peptide framework but has received less attention than thymic or pineal peptides.
📚 Key Reference: PMID: 2437141 (splenopentin immunomodulation)
Very limited human data. Preclinical safety appears acceptable. As a small bioregulatory peptide, toxicity risk is theoretically low. Consult your provider.
NOT FDA-approved. Research use only. Limited availability.