At present, in the production of animal vaccines, in order to reduce production costs, minimize purification losses of biological products, reduce the risk of interference or differences caused by uncertain protein or serum components, and improve the safety of biological products, serum-free culture media are mostly used.

However, during use, some viruses, such as foot-and-mouth disease virus, sometimes have the problem of good cell growth but low virus production. To overcome this problem, many manufacturers still add low concentration serum of 1% -3% during the virus production process.

If the impact of different components in serum on virus replication can be analyzed clearly, that is, which components promote virus replication and which components inhibit it, then adding serum components that promote virus replication in vaccine production and removing those that inhibit virus replication can effectively improve vaccine production.

For this reason, four mixed components (S1, S2, S3 and S4) in the serum were separated by affinity gel chromatography column from Ruite Biology, and virus culture experiments were carried out to observe the effect of the above different components on virus replication efficiency by cultivating insect baculovirus.

【1】 Observation of virus replication results through speckle experiment

Through speckle measurement experiments, it was found that compared with FBS, the number of speckles significantly increased when the concentration of S1 sample was above 1.3%. The number of speckles in sample S2 did not increase, but instead decreased. When the concentration of S3 sample is above 2.5%, the number of speckles significantly increases, while there is no significant increase in S1. There was no significant difference in the number of speckles in sample S4. The results are shown in Table 1 and Figures 1-5.

【2】 Fluorescence intensity observation of virus replication results

By observing the fluorescence intensity with the naked eye, it was found that compared with FBS, the fluorescence intensity of S1 sample significantly increased with increasing concentration. The fluorescence intensity of sample S2 did not increase. When the concentration of S3 sample is above 2.5%, the fluorescence intensity is significantly enhanced. The fluorescence intensity of sample S4 did not show significant changes. The results are shown in Figures 6-10.

【3】 Flow cytometry detection of virus replication results

Through flow cytometry detection, it was found that compared with FBS, the number of viruses in S1 samples significantly increased when the concentration was above 1.3%. The number of viruses in the S2 sample did not significantly increase. When the concentration of S3 sample is above 2.5%, the fluorescence intensity significantly increases. The above experiment confirms that S4 does not have a significant promoting effect on virus replication, so no flow cytometry was performed. The results are shown in Figures 11-13.

【 Conclusion 】

1. When the concentration of serum sample S1 is above 1.3%, it promotes the replication of BAC;

2. S2 did not have a promoting effect, but instead showed inhibition as the concentration of S2 increased;

3. When the concentration of S3 is above 2.5%, it also has a significant promoting effect;

4. The promoting effect of S4 is not significant.

In summary, compared with the original fetal bovine serum, adding a single serum component S1 has a more significant effect on improving the replication of BAC virus.

【 Discussion 】

The above study isolated different components from fetal bovine serum and observed their effects on virus replication, preliminarily confirming that the isolated component S1 has a significant promoting effect on insect baculovirus replication. As for whether this component has the same promoting effect on the replication of other viruses, Ruite Biology will further verify it in the future. The above research results, "The Effect of Different Components of Fetal Bovine Serum on Insect Baculovirus Replication," have been published in the 2nd issue of the Chinese Journal of Veterinary Medicine in 2019 (2019, 53 (2): 11-16). Click on 'View Original Text'.