HSL175

HSL175 is a **mouse monoclonal antibody (IgG3, κ)** that specifically targets human **L1 cell adhesion molecule (L1CAM)**, a protein overexpressed in small cell lung cancer (SCLC), particularly in the SCLC-N (NEUROD1-dominant) subtype. HSL175 is internalized by L1CAM-positive cells upon binding. It has been used as the antibody backbone in antibody–drug conjugate (ADC) research, where it is conjugated to cytotoxic agents (e.g., DT3C, a recombinant diphtheria toxin derivative) to selectively kill cancer cells through antigen-mediated internalization and subsequent induction of apoptosis. HSL175 was developed in-house at Sapporo Medical University and represents a tool for targeted therapy, with demonstrated preclinical efficacy against SCLC cell lines.