Generation of a scFv Derived from an IgM-Producing Hybridoma for the Detection of REST Expression in Premalignant Lesions and Invasive Squamous Cell Carcinoma.

Cervical cancer (CC) can be prevented through continuous screening and the timely detection of cervical intraepithelial neoplasia (CIN) using immunohistochemistry techniques to identify biomarker expressions. In a previous study, we proposed nuclear REST loss as a biomarker in precancerous lesions and CC; however, no validated antibodies are available for detecting REST in cytology or cervical tissues. Although we have developed an IgM-type anti-REST monoclonal antibody capable of detecting REST in liquid-based cytology cells, it was not useful for the detection of REST in cervical tissues by immunohistochemistry. The main objective of this study is to generate single-chain variable fragments (scFvs) for the clinical evaluation of REST in cervical tissues from women with CIN and CC. Using RNA from an IgM-producing hybridoma anti-REST, we conducted RT-PCR and PCR to obtain the coding sequences for the variable regions of the heavy and light chains. These sequences were joined with a linker to create a single-chain antibody. The scFv was then cloned into the pSyn1 vector, expressed in E. coli TG1, and purified through chromatography. Subsequently, it was characterized using immunological methods to assess its biological activity and employed to evaluate REST expression in cytological samples and cervical tissues. The anti-REST scFv represents an innovative detection tool that retains the antigen recognition of the parental IgM while overcoming its size limitation, enabling tissue penetration and detection of REST in cervical samples. Its application facilitates the identification of REST in cervical samples, reinforcing REST's potential as a diagnostic biomarker for CC and CIN.