Anti-Carcinoembryonic antigen monoclonal antibody, clone NM12F13

Background Intraperitoneal malignant cells detection in patients with gastric cancer is associated with a significant decrease in overall survival. The overall accuracy of cytological examination of peritoneal lavages, however, is quite low, and intraperitoneal recurrence has been observed even in patients with negative cytology. Immunocytochemistry and molecular techniques have been investigated to improve high-risk patients' identification with variable results. The aim of this study was to compare the performance of different laboratory methods applied to peritoneal washing, to improve the cytological identification of malignant cells. Methods We prospectively evaluated 21 patients who underwent surgery and peritoneal lavage for gastric cancer. Among them, 18 had negative cytology and three were positive for malignant cells. For each patient, immunohistochemistry with BerEP4 antibody was performed on seriate sections of cellblock preparation at different levels, using the method reported for sentinel nodes in other types of cancer. Paired frozen quotes of washing fluids were evaluated by qRT-PCR with primer for mRNA of Ceacam5. Results In 4 of 18 patients with previous negative routine cytology, isolated neoplastic cells in seriate sections of the cellblock inclusion have been found. Results showed to be coherent with molecular analysis for CEA mRNA. Conclusion The sensitivity and specificity of peritoneal washing analyses should be notably improved by immunohistochemistry applied to multilevel cellblock sectioning. The method is less expensive and more widely applicable than molecular analysis, in each laboratory setting. This approach allows detection of minimum peritoneal seeding in patients with gastric cancer.

Background: Yeast surface display (YSD) has proven to be a versatile platform technology for antibody discovery. However, the construction of antibody Fab libraries typically is a tedious three-step process that involves the generation of heavy chain as well as light chain display plasmids in different haploid yeast strains followed by yeast mating. Results: Within this study, we aimed at implementing a focused Golden Gate Cloning approach for the generation of YSD libraries. For this, antibodies heavy and light chains were encoded on one single plasmid. Fab display on yeast cells was either mediated by a two-directional promoter system (2dir) or by ribosomal skipping (bicis). The general applicability of this methodology was proven by the functional display of a therapeutic antibody. Subsequently, we constructed large antibody libraries with heavy chain diversities derived from CEACAM5 immunized animals in combination with a common light chain. Target-specific antibodies from both display systems were readily obtained after three rounds of fluorescence activated cell sorting. Isolated variants exhibited high affinities in the nanomolar and subnanomolar range as well as appropriate biophysical properties. Conclusion: We demonstrated that Golden Gate Cloning appears to be a valid tool for the generation of large yeast surface display antibody Fab libraries. This procedure simplifies the hit discovery process of antibodies from immune repertoires.