CD228 His Tag Protein, Cynomolgus

CD228, also known as melanotransferrin, MELTF, or MFI2, is a tumor-associated antigen with two major isoforms: membrane-bound mMFI2 and soluble sMFI2. mMFI2 is regarded as a potential therapeutic target for solid tumors, while sMFI2 has diagnostic value in malignancies, Alzheimer’s disease, and arthritis. Functionally, CD228 is involved in tumorigenesis, angiogenesis, endothelial cell migration, plasminogen activation, and transport across the blood-brain barrier. In melanoma, however, MELTF/CD228 may act as a tumor suppressor: CRISPR/Cas9 knockout enhanced invasion, increased subcutaneous tumor burden about fourfold, and raised lung metastasis signals nearly 18-fold, whereas high MELTF expression correlated with longer patient survival. Clinically, its limited normal-tissue expression makes CD228 an attractive antibody-drug conjugate (ADC) target. The first reported anti-CD228 ADC, SGN-CD228A (humanized hL49-MMAE, glucuronide linker, DAR 8), showed potent activity in melanoma, triple-negative breast cancer, and squamous NSCLC patient-derived xenograft models and entered phase I (NCT04042480). Novel humanized Ab-2F6A1-VcMMAE (DAR 4.9) and SNAP-tag-based anti-CD228-AURIF conjugates also showed selective cytotoxicity and in vivo efficacy. These findings highlight the dual diagnostic and therapeutic potential of CD228, supporting further development of CD228-targeted agents for precision oncology.