Inhibitory Effects of Circulating Natural Autoantibodies to CD47-derived Peptides on Oral Squamous Cell Carcinoma Cells

Abstract

Natural autoantibodies serve as an important anti-tumorigenic system due to its immune surveillance function. The present study aims to investigate whether circulating natural IgG autoantibodies against cluster of differentiation 47 (CD47) could suppress the proliferation of oral squamous cell carcinoma (OSCC) cells. Three OSCC cell lines were used for this study. The expression of fourteen tumor related genes including CD47 were tested. OSCC cells were grown, respectively, with 20% human plasma positive and negative for anti-CD47 IgG. Cell proliferation, apoptosis and invasion/metastasis were examined. The results showed that CD47 presented highest expression among all 14 genes detected in OSCC cells. Plasma anti-CD47 IgG significantly inhibited the viability of all three OSCC cell lines. The proportions of apoptotic cells were remarkably higher in OSCC cells treated with anti-CD47 IgG-positive plasma than those treated with IgG-negative plasma. Furthermore, the cell invasion/metastasis was attenuated evidently with the attribution of plasma anti-CD47 IgG. In conclusion, natural autoantibodies against CD47 may be a potential target for OSCC immunotherapy.