Human CSPG4 peptide

The chondroitin sulphate proteoglycan 4 (CSPG4), also known as high molecular weight-melanoma associated antigen (HMW-MAA), is a tumor-associated antigen that is expressed in more than 85% of surgically removed melanoma lesions but has restricted distribution in normal tissues. The diagnostic and therapeutic value of CSPG4 drives a need for sensitive and low-cost detection approaches. To this end, we developed a polyaniline/graphene oxide nanocomposite (PANI@GO) that was electrochemically codeposited on indium tin oxide (ITO) electrode. Glutaraldehyde mediated the covalent immobilization of CSPG4 specific antibody mAbD2.8.5 to construct a CSPG4 immunosensor using cell culture media and cell lysate as samples. The fully assembled impedimetric immunosensor was used to detect CSPG4 in CSPG4-positive cell lines M14/CSPG4 and MV3. No impedance signal changes could be observed from CSPG4-negative cell lines M14 and mAbMk2-23 showing the specificity of the CSPG4-impedimetric immunosensor. This low-cost, simple, and label-free analytical method is an alternative to enzyme-linked immunosorbent assay and flow cytometry in screening of CSPG4 in complex biological samples.

Reactivation of functionally-impaired anticancer T cells by programmed cell death protein 1 (PD-1) and programmed cell death receptor ligand-1 (PD-L1)-blocking antibodies shows prominent therapeutic benefit in advanced melanoma and patients with non-small cell lung cancer. However, current PD-L1-blocking antibodies lack intrinsic tumor selectivity. Therefore, efficacy may be reduced resulting from on-target and off-tumor binding to PD-L1-expressing normal cells. This may lead to indiscriminate activation of antigen-xperienced T cells, including those implicated in autoimmune-related adverse events. To direct PD-L1 blockade to chondroitin sulfate proteoglycan 4 (CSPG4)-expressing cancers and to reactivate anticancer T cells more selectively, we constructed bispecific antibody PD-L1xCSPG4. CSPG4 is an established target antigen that is selectively overexpressed on malignant melanoma and various other difficult-to-treat cancers. PD-L1xCSPG4 showed enhanced capacity for CSPG4-directed blockade of PD-L1 on cancer cells. Importantly, treatment of mixed cultures containing primary patient-derived CSPG4-expressing melanoma cells and autologous tumor-infiltrating lymphocytes with PD-L1xCSPG4 significantly enhanced activation status, IFN-gamma production, and cytolytic activity of anticancer T cells. In conclusion, tumor-directed blockade of PD-L1 by PD-L1xCSPG4 may improve efficacy and safety of PD-1/PD-L1 checkpoint blockade for treatment of melanoma and other CSPG4-overexpressing malignancies.