Potency Test Service of Influenza Vaccines
Creative Biolabs is committed to providing customers with one-stop vaccine development services. We are proficient in the design and evaluation of vaccines against a wide range of diseases and pathogens. In terms of vaccine potency testing, we can perform internationally recognized vaccine potency testing tests and design specific detection methods.
Background
Influenza viruses can accumulate mutations in their key parts or continually evolve by exchanging entire genome fragments. Therefore, the WHO needs to review the circulating influenza viruses every year and update the strains in the vaccine as needed. Vaccine developers and producers then prepare influenza vaccines based on published strains that are prevailing this year. This reality complicates the production and evaluation of influenza vaccines, makes it difficult to assess the effectiveness of vaccines, and also makes attempts to establish effective and consistent potency assays difficult. It is currently determined that the key target of the protective immune response triggered by influenza vaccine immunization is hemagglutinin (HA), and neuraminidase (NA) may also play a role.
Single Radial Immunodiffusion (SRID) Testing Services
Single radial immunodiffusion (SRD or SRID) was established, validated, and replaced agglutination assays in the 1970s to detect antigen content in influenza vaccines. Two reagents are required to perform SRID, one is an antibody that reacts with the test strain, and the other is a reference antigen of known potency with homology to the exact strain used in the vaccine. Briefly, the assay is carried out by digging wells in an agarose plate containing the appropriate concentration of antibody, then placing the serially diluted test antigen into the well. The antigen diffuses until it reaches an area equal to the antibody dilution, where a precipitation loop is formed. The excess antibody is washed away and plate is air-dried as well as stained, and the size of the loop is observed and measured. The higher the antigen content, the larger the loop area.
The SRID test is a common potency testing in the influenza vaccine industry. It is widely used to determine the efficacy of hemagglutinin content in the final vaccine product. It measures the antigens that are most relevant for protection and are in the natural conformation. In addition, SRD has been used for decades, so there is a lot of historical data and experience for reference, which is very valuable in such a complex field as influenza vaccine.
Fig.1 SRID assay of influenza haemagglutinin. (Philip D. Minor, 2014)
NA Activity Testing Services
More and more evidence shows that the immunity against NA induced by neuraminidase (NA) in influenza vaccine can reduce the shedding of influenza virus, remit the severity of influenza disease, and even have a strong impact on the prognosis. Recent studies have also shown that broadly reactive antibodies against NA can offer protection against a range of influenza subtypes. However, the content of NA in influenza vaccines is largely unregulated and unknown. Therefore, with the continuous deepening of influenza research and the gradual understanding of the role of NA in influenza vaccines, the determination of NA potency in influenza vaccines has become an important content in the development and evaluation of influenza vaccines. Enzyme activity is often used to verify the presence of NA in influenza vaccines. Creative Biolabs uses the MUNANA (2’-(4-methylumbelliferyl)-a-D-N-acetylneuraminic acid) test to detect NA activity in influenza vaccines. The activity of a sample can be calculated by cleaving a sialic acid-containing compound into a fluorescent product and measuring the rate of fluorescence accumulation. In addition, we have also developed immunochemical-based methods to detect NA potency in influenza vaccines.
Creative Biolabs provides a full range of technical support for vaccine developers, including the most important aspect of vaccine evaluation-potency testing. For influenza vaccine potency testing, we can provide industry-accepted SRID tests and also offer complementary NA activity testing services to complete your vaccine data.
Reference
- Philip D. Minor; (2014). “Assaying the Potency of Influenza Vaccines.” Vaccines (Basel). 3(1): 90-104.
All of our products can only be used for research purposes. These vaccine ingredients CANNOT be used directly on humans or animals.