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Adjuvants in Veterinary Vaccines: From Traditional to Innovative

Published: 2025-3-17 , Posted by: Vuroyal

In the field of veterinary vaccines, adjuvants are key components that enhance the immune response of vaccines. Adjuvants not only improve the efficacy of vaccines but also reduce the amount of antigen needed, thereby lowering the production costs of vaccines. This article will introduce some common adjuvants used in veterinary vaccines, particularly those based on saponins, and their applications in both commercial and research settings.

Traditional Adjuvants in Commercial Vaccines

Currently, most veterinary vaccines on the market use traditional adjuvants such as aluminum salts (e.g., aluminum hydroxide) and oil emulsions. These adjuvants perform well in enhancing the immune response of vaccines but have some limitations, such as strong local reactions or limited immune efficacy.

1、Bovine Respiratory Disease Vaccine (Pneumo-4)

Target Species: Cattle
Pathogens: Bovine Viral Diarrhea Virus (BVDV), Bovine Herpesvirus-1 (BoHV-1), Bovine Respiratory Syncytial Virus (BRSV), etc.
Adjuvants: Aluminum hydroxide gel or mineral oil
Characteristics: Widely used to control bovine respiratory diseases, some formulations combine aluminum salts and oil emulsions to enhance efficacy.

2、Pasteurella Multocida Vaccine

Target Species: Cattle, Poultry, Swine, Sheep
Pathogen: Pasteurella multocida
Adjuvants: Aluminum hydroxide (used in 57.8% of formulations), oil-based adjuvants (e.g., mineral oil)
Characteristics: Most commercial vaccines use aluminum hydroxide as an adjuvant, especially in cattle vaccines.

3、Newcastle Disease Vaccine (Inactivated)

Target Species: Poultry
Pathogen: Newcastle Disease Virus (NDV)
Adjuvants: Oil emulsion
Characteristics: Often combined with other antigens (e.g., H9 influenza), oil adjuvants enhance long-term immunity.

Novel Adjuvants in Vaccine Research

With advancements in vaccine technology, researchers are exploring novel adjuvants to improve vaccine efficacy, safety, and cost-effectiveness. Among these, saponins (such as Vet-Sap and QS-21) have garnered attention for their ability to enhance both humoral and cellular immune responses.

1、Bovine Viral Respiratory Vaccine (Pneumo-4 Variant)

Target Species: Cattle
Pathogens: BVDV, BoHV-1, BRSV, etc.
Adjuvants: Vet-Sap (saponin) combined with carbomer stabilizer
Research Progress: This vaccine induces immunity for approximately 9 months in cattle, reducing the need for frequent booster shots, and has milder local reactions compared to oil emulsions.

2、Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) Subunit Vaccine

Target Species: Swine
Pathogen: Recombinant PRRSV protein
Adjuvants: QS-21 (purified saponin) combined with liposomes
Research Progress: QS-21 outperforms aluminum hydroxide in inducing cross-protective immunity and has fewer side effects.

3、Avian Influenza (H5/H7) Nanoparticle Vaccine

Target Species: Poultry
Pathogen: Recombinant H5 or H7 hemagglutinin protein
Adjuvants: Vet-Sap combined with nanoparticles (e.g., ISCOMs)
Research Progress: Vet-Sap enhances CD8+ T cell responses, with lower injection site inflammation, making it suitable for highly pathogenic avian influenza.

4、Canine Leishmaniasis DNA Vaccine

Target Species: Dogs
Pathogen: Leishmania infantum antigen
Adjuvants: QS-21 combined with DNA plasmid delivery
Research Progress: QS-21 enhances the immune response to DNA-encoded antigens, promoting a Th1-biased immune response, suitable for the prevention of leishmaniasis.

Advantages and Challenges of Saponin Adjuvants

Advantages:

Dual Immune Stimulation: Saponins can activate both Th1 (cellular immunity) and Th2 (humoral immunity) responses, whereas traditional adjuvants like aluminum salts primarily activate Th2 responses.
Fewer Side Effects: Compared to oil emulsions, saponin adjuvants cause milder local reactions, making them suitable for companion animals and livestock.

Challenges:

Hemolytic Activity: Saponins have some hemolytic activity, which may damage red blood cells. Researchers are mitigating this side effect by combining saponins with liposomes or nanoparticles.
Sustainability: Overharvesting of Quillaja saponaria (the primary source of saponins) has raised sustainability concerns. Researchers are exploring alternative plant sources for saponins. Meanwhile, Desert King employs an integrated approach of forest management, selective technology, and plantations to ensure a continuous supply of products now and in the future. Additionally, they hold patents on methods for selecting superior saponin-based biomaterials, further expanding and securing available production to meet customer supply commitments—continuous innovation enhances the ability to deliver products on time and in quantity.

Future Trends in Novel Adjuvants

Multifunctional Adjuvants: Such as polyphosphazenes, which can act as both adjuvants and antigen delivery systems, reducing antigen usage and improving stability.
Precision Immunity: Using Toll-like receptor (TLR) agonists or nanotechnology to activate specific immune pathways (e.g., Th1 or cytotoxic T cell responses).
Innovative Delivery Methods: Oral and mucosal delivery are becoming research hotspots, simplifying large-scale vaccination.

Conclusion

As veterinary vaccine technology continues to advance, adjuvant research is also innovating. From traditional aluminum salts and oil emulsions to novel saponin adjuvants, researchers are striving to develop more effective and safer vaccine formulations. In the future, with the development of multifunctional adjuvants and precision immunity technologies, veterinary vaccines will better serve the health of livestock and companion animals.

If you are interested in specific research progress on a particular vaccine or adjuvant, feel free to leave a comment for discussion!

References:

This article is based on veterinary vaccine research data up to March 3, 2025.