Application of Cobetter ViruClear™ Virus Removal Filters in the Production Process of Herpes Vaccine

Herpes zoster is caused by the varicella-zoster virus. Infection with this virus during childhood leads to chickenpox, and after recovery, the virus remains dormant in the nerve ganglia. When individuals age, experience fatigue, or have weakened immune systems, the virus may be "reactivated," spreading along nerve fibers to the skin and causing clusters of blisters and severe pain. Vaccination is key to preventing herpes zoster. This article will briefly introduce the application of Cobetter's virus removal filters in the production process of the herpes zoster vaccine.

Production Process of Herpes Vaccine

In the last century, attenuated virus vaccines were widely used. Currently, the mainstream involves recombinant protein vaccines, which are produced using highly mature and safe technologies. In addition, newer types such as mRNA herpes zoster vaccines are currently under clinical research. Taking the CHO cell-based recombinant herpes vaccine as an example, it can produce antigens with a structure most similar to the natural form and optimal immunogenicity. At the same time, it relies on a mature, stable, and scalable industrial production process, ensuring high quality, high yield, and feasibility for global supply.

The products expressed by CHO cells are first subjected to depth filtration to obtain the supernatant. This is followed by anion exchange chromatography to capture the target protein. After buffer exchange, hydrophobic interaction chromatography is used for intermediate purification, and cation exchange chromatography is employed for polishing to remove process-related and product-related impurities.

Chromatography Purification Process of Recombinant Herpes Zoster Vaccine

Virus filtration, as the most critical virus removal step in the entire process, is typically placed after the polishing step. However, considering the properties of the target protein and the purification steps it undergoes, the virus filtration of the recombinant protein for the herpes vaccine faces challenges such as low protein concentration, slow flow rate, and rapid flux decay. Without changing the whole process, there is a high demand for the fouling resistance of the virus filters, needing extensive screening experiments to identify the most suitable filters.

Case Study of Virus Filtration in the Production Process of Herpes Zoster Vaccine

Filtration Performance of Cobetter PNY＋ViruClear VF Plus Filters

(Protein solution: ~1.5g/L   Filtration pressure: 30psi)

Experimental Conclusion:

In this case, a combination of PNY and ViruClear filters was employed in series. The target protein was relatively easy to filter, enabling the maintenance of a stable flux. 

Filtration Performance of Cobetter PDT＋ViruClear VF Plus Filters

(Protein solution: 2~3g/L   Filtration pressure: 30psi)

Experimental Conclusion:

In this case, the use of PNY + ViruClear in series filtration resulted in continuous flux decay. Further process optimization requires the adoption of PDT + ViruClear VF Plus. However, it should be noted that depth filtration-based virus removal protective filters may exhibit potential adsorption effects, leading to low protein/antigen yield.

Filtration Performance of Cobetter PNY＋ViruClear VF Plus/RCH Filters

(Protein solution: 0.1~1.0g/L   Filtration pressure: 30psi)

Experimental Conclusion:

If the target protein itself has strong hydrophobicity and the buffer components contain special ingredients such as stabilizers, it may lead to excessively rapid flux decay. In this case, after switching to the ViruClear RCH virus removal filter with regenerated cellulose membrane, the flux can be maintained at a stable level both before and after filtration.

Case Study Summary

1.The ViruClear PNY filter (Nylon membrane) is recommended as a pre-filter for virus removal, as it effectively adsorbs hydrophobic impurities without significantly impacting protein or antigen yield.

2.The ViruClear VF Plus filter (PES membrane) is suitable for rocombinant target protein with low concentration and weak hydrophobicity. If higher loading capacity is required, ViruClear VF Plus X filter (PES) is recommended.

3.The ViruClear RCH filter (RC membrane) is suitable for target protein with high concentration and strong hydrophobicity which are prone to fouling.

With a large amount of collaborations with clients on filtration processes for recombinant CHO-expressed herpes zoster vaccines, Cobetter has accumulated substantial case studies for virus filtration steps, supporting customers in scaling up to hundred-liter production, completing VC validation for IND and BLA submissions, and ultimately establishing a platform-based virus filtration process solution.