Eukaryotic ribosome display for antibody discovery: A review

Monoclonal antibody biologics have significantly transformed the therapeutic landscape within the biopharmaceutical industry, partly due to the utilisation of discovery technologies such as the hybridoma method and phage display. While these established platforms have streamlined the development process to date, their reliance on cell transformation for antibody identification faces limitations related to library diversification and the constraints of host cell physiology. Cell-free systems like ribosome display offer a complementary approach, enabling antibody selection in a completely in vitro setting while harnessing enriched cellular molecular machinery. This review aims to provide an overview of the fundamental principles underlying the ribosome display method and its potential for advancing antibody discovery and development.

Ribosome display and selection of single-chain variable fragments effectively inhibit growth and progression of microspheres in vitro and in vivo

Distinguishing the surface markers of cancer stem cells (CSCs) is a useful method for early diagnosis and treatment of tumors, as CSCs may participate in tumorigenesis and metastasis by migrating into the circulatory system. However, the potential targets of CSCs are expressed at low levels in the natural state and are always changing. Thus, dynamic screening has been reported to be an effective measure for exploring CSC markers. In recent years, diverse single-chain variable fragments (scFvs) have been widely used in immunotherapy. In this study, we determined that the scFvs, screened using RD, had a high affinity to microspheres and could inhibit their progression. We also observed that the selected scFvs underwent evolution in vitro, and antitumor-associated proteins were successfully expressed. Combined with chemotherapy, the scFvs had a synergistic effect on the inhibition of the microspheres' progression in vitro and in vivo, which could be ascribed to their high affinity for stem-like cells and the inhibition of the microspheres' collective behaviors. In addition, proteins inhibiting CD44⁺ /CD24⁺ and MAPK were involved. Our data indicated that dynamic screening of the scFvs in a natural state was of great significance in the inhibition of the microspheres in vitro and in vivo.

Adding Functions to Biomaterial Surfaces through Protein Incorporation

The concept of biomaterials has evolved from one of inert mechanical supports with a long-term, biologically inactive role in the body into complex matrices that exhibit selective cell binding, promote proliferation and matrix production, and may ultimately become replaced by newly generated tissues in vivo. Functionalization of material surfaces with biomolecules is critical to their ability to evade immunorecognition, interact productively with surrounding tissues and extracellular matrix, and avoid bacterial colonization. Antibody molecules and their derived fragments are commonly immobilized on materials to mediate coating with specific cell types in fields such as stent endothelialization and drug delivery. The incorporation of growth factors into biomaterials has found application in promoting and accelerating bone formation in osteogenerative and related applications. Peptides and extracellular matrix proteins can impart biomolecule- and cell-specificities to materials while antimicrobial peptides have found roles in preventing biofilm formation on devices and implants. In this progress report, we detail developments in the use of diverse proteins and peptides to modify the surfaces of hard biomaterials in vivo and in vitro. Chemical approaches to immobilizing active biomolecules are presented, as well as platform technologies for isolation or generation of natural or synthetic molecules suitable for biomaterial functionalization.

Characterization of Anti-Citrinin Specific ScFvs Selected from Non-Immunized Mouse Splenocytes by Eukaryotic Ribosome Display

Single chain variable fragments (scFvs) against citrinin (CIT) were selected from a scFv library constructed from the splenocytes of non-immunized mice by an improved eukaryotic ribosome display technology in this study. Bovine serum albumin (BSA)/ CIT-BSA and ovalbumin (OVA)/ CIT-OVA were used as the antigens to select specific anti-CIT scFvs. Eukaryotic in situ RT-PCR method was used to recover the selected mRNA after every affinity selection. After six rounds of ribosome display, expression vector pTIG-TRX carrying specific scFv DNAs were constructed and transformed into Escherichia coli BL21 (DE3) for protein expression. Thirteen positive clones were selected out of which three (designated 23, 68 and 109) showed high binding activity and specificity to CIT by indirect ELISA, while no clone showed binding activity with carrier proteins. The three scFvs showed high specificity to CIT and the cross reactivity with other mycotoxins was below 0.01% as determined by indirect competitive ELISA. These specific scFvs offer a potential novel immunoassay method for CIT residues. This study confirmed the effectiveness of the improved eukaryotic ribosome display system and could be used as a reference for the selection of scFvs specific to other small molecules using ribosome display.

Biotechnology techniques for the development of new tumor specific peptides

Peptides, proteins and antibodies are promising candidates as carriers for radionuclides in endoradiotherapy. This novel class of pharmaceuticals offers a great potential for the targeted therapy of cancer. The fact that some receptors are overexpressed in several tumor types and can be targeted by small peptides, proteins or antibodies conjugated to radionuclides has been used in the past for the development of peptide endoradiotherapeutic agents such as (90)Y-DOTATOC or radioimmunotherapy of lymphomas with Zevalin. These procedures have been shown to be powerful options for the treatment of cancer patients. Design of new peptide libraries and scaffolds combined with biopanning techniques like phage and ribosome display may lead to the discovery of new specific ligands for target structures overexpressed in malignant tumors. Display methods are high throughput systems which select for high affinity binders. These methods allow the screening of a vast amount of potential binding motifs which may be exposed to either cells overexpressing the target structures or in a cell-free system to the protein itself. Labelling these binders with radionuclides creates new potential tracers for application in diagnosis and endoradiotherapy. This review highlights the advantages and problems of phage and ribosome display for the identification and evaluation of new tumor specific peptides.

Grading the commercial optical biosensor literature-Class of 2008: 'The Mighty Binders'

Optical biosensor technology continues to be the method of choice for label-free, real-time interaction analysis. But when it comes to improving the quality of the biosensor literature, education should be fundamental. Of the 1413 articles published in 2008, less than 30% would pass the requirements for high-school chemistry. To teach by example, we spotlight 10 papers that illustrate how to implement the technology properly. Then we grade every paper published in 2008 on a scale from A to F and outline what features make a biosensor article fabulous, middling or abysmal. To help improve the quality of published data, we focus on a few experimental, analysis and presentation mistakes that are alarmingly common. With the literature as a guide, we want to ensure that no user is left behind.

Selection of anti-sulfadimidine specific ScFvs from a hybridoma cell by eukaryotic ribosome display

BACKGROUND

Ribosome display technology has provided an alternative platform technology for the development of novel low-cost antibody based on evaluating antibiotics derived residues in food matrixes.

METHODOLOGY/PRINCIPAL FINDINGS

In our current studies, the single chain variable fragments (scFvs) were selected from hybridoma cell lines against sulfadimidine (SM(2)) by using a ribosome library technology. A DNA library of scFv antibody fragments was constructed for ribosome display, and then mRNA-ribosome-antibody (MRA) complexes were produced by a rabbit reticulocyte lysate system. The synthetic sulfadimidine-ovalbumin (SM(2)-OVA) was used as an antigen to pan MRA complexes and putative scFv-encoding genes were recovered by RT-PCR in situ following each panning. After four rounds of ribosome display, the expression vector pCANTAB5E containing the selected specific scFv DNA was constructed and transformed into Escherichia coli HB2151. Three positive clones (SAS14, SAS68 and SAS71) were screened from 100 clones and had higher antibody activity and specificity to SM(2) by indirect ELISA. The three specific soluble scFvs were identified to be the same molecular weight (approximately 30 kDa) by Western-blotting analysis using anti-E tag antibodies, but they had different amino acids sequence by sequence analysis.

CONCLUSIONS/SIGNIFICANCE

The selection of anti-SM(2) specific scFv by in vitro ribosome display technology will have an important significance for the development of novel immunodetection strategies for residual veterinary drugs.