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Introduction to Vaccine Adjuvants
Vaccine adjuvants are a class of substances that can non-specifically modify or enhance the body’s antigen-specific immune response, thereby playing a supportive role in vaccination. Adjuvants help induce long-lasting and efficient specific immune responses, ultimately improving the body’s protective immunity.
Also known as immunomodulators or immune enhancers, adjuvants are additives used in vaccines. When administered before or together with an antigen, they can enhance the immune response to the antigen or alter the type of immune response generated. Adjuvants are considered non-specific immune enhancers and are not antigenic themselves. An ideal adjuvant not only strengthens the immune response, but also enables the body to achieve optimal protective immunity.
As research into immunological adjuvants continues to advance, new types of adjuvants are constantly being identified. Common vaccine adjuvants can generally be classified into the following categories:
Aluminum-based adjuvants, oil emulsion adjuvants, microbe-derived adjuvants, propolis adjuvants, levamisole adjuvants, liposomal adjuvants, traditional Chinese medicine-derived adjuvants, and small peptide adjuvants.
Functions of Adjuvants:
(1) Convert non-antigenic substances into effective antigens;
(2) Enhance circulating antibody levels or induce more effective protective immunity;
(3) Alter the type of circulating antibodies produced;
(4) Enhance the capacity for cell-mediated hypersensitivity responses;
(5) Induce experimental autoimmunity or other types of hypersensitivity disorders;
(6) Protect antigens—especially DNA and RNA—from enzymatic degradation in vivo.
In the preparation of hydrophilic vaccine adjuvants, it is often necessary to increase sample concentration and remove specific ions through buffer exchange in order to improve downstream process efficiency.
For example, traditional aluminum hydroxide adjuvant preparation is mainly achieved by precipitation. The core step involves adding an alkaline solution to an aluminum salt solution under controlled conditions to generate aluminum hydroxide precipitates. The overall process typically includes centrifugation, washing, and suspension preparation.
Conventional aluminum-based adjuvants are often purified by dialysis to remove unreacted salt and alkaline solutions. However, dialysis is time-consuming and inefficient. In addition, batch-to-batch stability is often insufficient, and issues such as aggregation and sedimentation may occur, affecting product shelf life and clinical safety.
By contrast, the use of tangential flow filtration at this stage not only improves process efficiency, but also enables scalable production. As a result, tangential flow products have been widely used in the development and manufacturing of vaccine adjuvants.
Case Studies of Cobetter Tangential Flow Products in Vaccine Adjuvant Preparation
1. Tangential Flow Filtration of Aluminum Hydroxide Adjuvant
Aluminum hydroxide [Al(OH)₃] was prepared through the chemical reaction of AlCl₃·6H₂O and NH₃·H₂O, producing particles with a size of 6–8 μm. During preparation of the target material, NH₄⁺ and Cl⁻ ions are introduced simultaneously and need to be removed in the downstream process.
A Cobetter hollow fiber filter with a 750 kDa MWCO and 1.0 mm fiber ID (Part No.: HFEPI07501030P) was used for diafiltration to remove NH₄⁺ and Cl⁻ ions.
After diafiltration and concentration, the residual levels of NH₄⁺ and Cl⁻ ions in the process fluid were tested and found to meet the required standards.
2. Tangential Flow Filtration of Saponin Adjuvant
For the QS-21 triterpenoid saponin vaccine adjuvant, the sample remains structurally stable in solution as micellar aggregates. A Cobetter PES ultrafiltration TFF cassette with a 10 kDa MWCO (Part No.: UFELA0010002P) was used for concentration and diafiltration of the intermediate product.
After concentration and diafiltration, the solution reached the target concentration and the required buffer was successfully exchanged, while product recovery met process requirements.
3. Tangential Flow Filtration of Cytokine-Based Adjuvants
For GM-CSF adjuvants (molecular weight 14.5 kDa), a Cobetter PES ultrafiltration cassette with a 5 kDa MWCO (Part No.: UFELA0005010P) was used for ultrafiltration concentration of the intermediate product.
After concentration using the Cobetter TFF cassette, the solution reached the target concentration, and the product yield met process requirements.
In summary, this series of experimental cases demonstrates that Cobetter tangential flow filtration products deliver outstanding overall performance in ultrafiltration steps during vaccine adjuvant preparation. They not only maintain high and stable flux, effectively improving processing efficiency, but also achieve excellent target component recovery. Combined with superior cassette recovery performance, long-term operational costs are significantly reduced. These attributes make Cobetter TFF products a reliable and efficient technological choice for adjuvant production. As a trusted partner in the vaccine industry, Cobetter remains committed to providing one-stop solutions covering filtration, separation, purification, and single-use solutions for various adjuvants and solutions.
