Tet-On System

We have consistently offered our clients a specialized service for producing recombinant antibodies within their specified cells. The case study below exemplifies our process, focusing on a customer who was interested in rapidly obtaining purified recombinant anti-CD33 antibodies utilizing their proprietary DNA sequence.

Antibody-Producing Cell Screening:

The primary objective at this stage is to isolate high-capacity antibody-producing cells. After infection with high-titer lentivirus produced using the customer’s DNA sequence, the transduced cells underwent puromycin selection. Colonies of infected cells were then chosen specifically to identify those with high antibody-producing capacities. We use the culture medium from each cell colony and screen it with Western-blot (Figure 3A). Typically, after screening 25 to 30 colonies, we can establish a stable, high-producing cell line.

Purification of rAb and Gel Image Analysis:

Once we’ve identified high producing cells, the next step is the purification of the antibody. The success of this purification is then verified through a gel image stained with Coomassie blue, emphasizing the purified rAb after its treatment with DTT (Dithiothreitol) (Figure 3B). 

Functional Validation:

In this case, we produced a recombinant anti-human CD33 antibody. To assess its functionality, the antibody was fluorescently labeled and used to stain human AML cells provided by the client. The results confirm the functionality of the recombinant anti-CD33 antibody, given its robust binding affinity to the cells, which is known to exhibit surface CD33 expression based on separate staining with commercially available fluorescent anti-CD33 antibodies.