A llama was immunized with the HER2-expressing ovarian cancer cell line SKOv3 and a sdAb phage display library was built and used to perform biopannings. The first round of selection was performed on a purified recombinant HER2 ectodomain fused to a human Fc portion (HER2-Fc) followed by a second round on an HER2-positive SKBr3 cell line. After selection, 188 clones were screened and 92 clones were found to be positive by ELISA on HER2 positive cells. Twenty clones were analyzed by sequencing, and all of them corresponded to a unique clone named C7b.
