Creative Biolabs is a leading service provider of phage display antibody library construction and screening. In order to select antibodies with high affinity and specificity, we have developed a serial of biopanning methods, such as solid-phase selection, cell-based selection, and in vivo selection. Among of them, solution-sorting screening is an alternative selection method of great importance. Creative Biolabs developed an optimized procedure to selection custom antibody with antigen in solution.
The phage display library screening could be conducted on various antigen sources, such as purified antigens, cell lysates, whole cells, and tissues. Nowadays, selection on purified antigen remains the most feasible and effective approach. However, the effectiveness of this method depends on how the antigens are immobilized. The traditional solid-phase selection involves in the coating of antigens onto solid surfaces. The plastic surface such as microtiter plate or immunotube directly adsorbs the purified antigen, resulting in some conformational change of the protein to expose the hydrophobic interfaces toward the plastic. Although it is an effective method, it still cannot apply to all the targets. Some selected binders may not be able to bind the soluble conformation of the antigen. As an alternative, the in-solution panning approach introduces the target binding in solution, overcomes the problem of conformation changes when coating on the solid phase.
The process of solution-sorting screening
The soluble target will incubate with the phage display antibody library first. The target may include 6xHis, GST or MBP affinity tag, as well as labeled with biotin. Precise control of the antigen concentration could be obtained by using labeled antigens. Meanwhile, reducing the concentration of the antigen will allow the selection of phage antibodies with high affinity due to the higher stringency of the selection.
Following the incubation, the phage-antigen complex will be captured by either streptavidin, glutathione or nickel beads. Magnetic selection will be performed to enrich the bound phage antibodies. In order to avoid the fortuitous selection of phage antibodies that specifically bind the beads, a negative selection could be included with the phage incubating with beads in the absence of target. In this step, the supernatant will be collected for the next round of selection. With three rounds of selections, the binders can be enriched.
Figure. 1 Solution-sorting screening.
Creative Biolabs has extensive expertise in phage display and the proven records of generating high-affinity antibodies in a cost-effective and timely manner. Solution-sorting screening is advantageous in precise control of the antigen concentration and avoiding the possibility of the conformation change of the target antigen. Integrated with other advanced technologies, such as affinity maturation and antibody engineering, we are able to offer the most comprehensive screening services and tailored proposal to isolate desired binders from your interested phage display libraries.