Autoantibody Formation and Mapping of Immunogenic Epitopes against Cold-Shock-Protein YB-1 in Cancer Patients and Healthy Controls

Abstract

Cold shock Y-box binding protein-1 participates in cancer cell transformation and mediates invasive cell growth. It is unknown whether an autoimmune response against cancerous human YB-1 with posttranslational protein modifications or processing develops. We performed a systematic analysis for autoantibody formation directed against conformational and linear epitopes within the protein. Full-length and truncated recombinant proteins from prokaryotic and eukaryotic cells were generated. Characterization revealed a pattern of spontaneous protein cleavage, predominantly with the prokaryotic protein. Autoantibodies against prokaryotic, but not eukaryotic full-length and cleaved human YB-1 protein fragments were detected in both, healthy volunteers and cancer patients. A mapping of immunogenic epitopes performed with truncated E. coli-derived GST-hYB-1 proteins yielded distinct residues in the protein N- and C-terminus. A peptide array with consecutive overlapping 15mers revealed six distinct antigenic regions in cancer patients, however to a lesser extent in healthy controls. Finally, a protein cleavage assay was set up with recombinant pro- and eukaryotic-derived tagged hYB-1 proteins. A distinct cleavage pattern developed, that is retarded by sera from cancer patients. Taken together, a specific autoimmune response against hYB-1 protein develops in cancer patients with autoantibodies targeting linear epitopes.

Close Links between Cold Shock Proteins and Cancer

“…They performed a systematic analysis of autoantibody formation directed against conformational and linear epitopes within the protein and detected autoantibodies against prokaryotic, but not eukaryotic full-length and cleaved human YB-1 protein fragments in both healthy volunteers and cancer patients. This study highlights the potential of using YB-1 autoantibodies as a diagnostic marker for cancer [1].…”

Human Autoantigen Atlas: Searching for the Hallmarks of Autoantigens

“…52 Belogurov et al's study found that serological AAbs to both myelin basic protein (MBP) protein and fragments (48−70 and 85−170) were significantly higher in multiple sclerosis (MS) patients than healthy controls. 48 Full-length and cleaved human YB-1 protein fragments of the Cold Shock Y-box Binding Protein-1 (YB-1) were also detected in healthy volunteers and cancer patients, 53 indicating that the AAbs could be produced to the protein fragments, which might be generated by protein degradation or synthesis.…”