Naptumomab estafenatox (ABR-217620) is a fusion protein that combines an anti-5T4 antibody with a SEA/E-120 superantigen, categorized as a tumor targeting superantigen (TTS). It has potential applications in lung cancer research [1].

Naptumomab estafenatox (0.001-10000 pM; 4 hours) exhibits EC50 values against Staphylococcal enterotoxin A (SEA)-mediated T cell responses in Caki-2 and Raji cells of 20 and 30000 pM, respectively [1]. For SEA/E-120 mediated T cell responses, its EC50 values are 0.1 and 100000 pM for the same cell lines [1]. Additionally, naptumomab estafenatox (1 pM-1 μM; 4 days) promotes human lymphocyte proliferation in a dose-dependent manner [1]. Cell Proliferation Assay [1] Cell Line: Human peripheral blood mononuclear cell (PBMC) line Concentration: 1 pM-1 μM Incubation Time: 4 days Result: Induced proliferation of human PBMCs in a dose-dependent way, requiring higher concentrations compared to SEA wt (C242Fab-SEA) and anatumomab mafenatox.

Naptumomab estafenatox (0.016 mg; intravenous injection, once daily for 8 days) exhibits antitumor activity in immunodeficient mice with Calu-1 tumors [1]. Animal Model: SCID mice implanted with Calu-1 tumors and injected with PBMCs [1]. Dosage: 0.016 mg via intravenous administration for 8 consecutive days. Result: Notably decreased tumor mass.