Why is it necessary to perform in vivo detection of exogenous viruses?
In the system of viral safety evaluation for biological products, in vivo animal inoculation is a long-established and mature non-specific detection method. It involves inoculating the test sample into sensitive laboratory animals or chicken embryos, utilizing the animal's intact life system and immune response to reveal potential infectious viral contamination. While next-generation sequencing (NGS) and other molecular methods have been accepted by some regulations as modern alternatives with technological advancements, the classic in vivo method, due to its unique biological detection principles, still holds an important position in pharmacopoeias of many countries worldwide and remains one of the cornerstone methods for viral safety evaluation.
Core technology: In vivo inoculation method for animals and chicken embryos
In vivo inoculation in animals and chicken embryos is an in vivo detection technique that utilizes a live host system for broad-spectrum virus screening. Its core principle is as follows: the sample to be tested is inoculated into a susceptible animal host (puppy, adult rat, guinea pig, rabbit, or chicken embryo) via multiple routes (intracerebral, peritoneal, yolk sac, allantoic cavity, etc.). If an infectious virus is present in the sample, it can replicate within the host and produce direct pathogenic effects (characteristic clinical symptoms, histopathological damage, or death). By closely monitoring and recording animal survival rates, the presence of infectious live viruses in the sample can be demonstrated indirectly. This method can detect viruses that are difficult to proliferate in in vitro cell culture or do not produce typical lesions (such as certain enteroviruses and arboviruses), thus serving as a crucial regulatory supplement to in vitro virus screening systems.
In the current global regulatory system for biological products, the application logic of in vivo inoculation has undergone profound changes, and its core requirements can be summarized as follows :
The release of the Chinese Pharmacopoeia (2025 edition) marks a key shift: the animal inoculation method has moved from "mandatory testing" to a "risk-based strategy." The regulations emphasize the need for risk assessment in conjunction with cell and process considerations, and open up alternative pathways such as validated methods like NGS. They also impose stricter requirements on key parameters (such as the 28-day observation period) to achieve precise and efficient virus safety control.
Once the method is determined, special attention must be paid to the differences in operational details across different regulatory systems. Major global pharmacopoeias (such as ChP, USP, EP) have specific regulations regarding key technical parameters such as animal age, weight, number, route of administration, and observation period. The protocol design must strictly adhere to the latest regulations applicable to the target market to achieve precise compliance adaptation.
Reference information: The target viral lineages listed are excerpted from Table 5 (In vivo virus screening test) of USP-NF General Rules <1237> "Virus Detection Methods".
Core Technologies: Antibody Production Assays (MAP, RAP, and HAP)
Antibody production assays (MAP/RAP/HAP) are in vivo specific screening methods for known viroginseng groups of a specific species. The core principle is as follows: the sample to be tested is inoculated into a susceptible host animal that is specific pathogen-free (SPF). If the sample contains active virus or viral antigens, a specific humoral immune response will be elicited in the host. After a prescribed observation period (usually 28 days or longer), the presence of specific antibodies against the target virus in the animal's serum is detected. The detection of serum antibodies is direct evidence of the presence of infectious virus or immunogenic viral components in the sample.
Reference: The viral lineages listed in the table below are derived from the ICH Q5A(R2) guideline (Table 3) and cover the main target viruses that the guideline requires screening
Our company provides you with professional services
Our testing system strictly adheres to mainstream international standards such as the Chinese Pharmacopoeia, USP, EP, and ICH. We have mature compliance solutions and successful cases to support simultaneous registration and application in multiple regions, including China, the US, and Europe, paving the way for your products' efficient globalization.
We offer professional risk assessment and strategy planning services. Based on the latest regulations, we systematically analyze your cell history and manufacturing processes, scientifically demonstrate and customize the optimal detection pathway (traditional in vivo method/NGS/combination validation) to help you achieve the best balance between compliance reliability and R&D efficiency.
We operate both mature, classic in vivo testing platforms and proven modern platforms such as NGS. We can develop testing strategies tailored to the product's stage and risk characteristics, such as using NGS for efficient initial screening followed by in vivo confirmation, providing you with flexible and reliable dual technical support.
We have established a rigorous animal supply chain system, carefully selecting SPF-grade mice, rats, hamsters, guinea pigs, and chicken embryos as animal models to ensure that their strains, ages, and weights meet the requirements of multiple national pharmacopoeias. The entire process is led by a team of senior experts, from inoculation and observation to pathological analysis, ensuring precise procedures and reliable data.
We rigorously adhere to international guidelines for comprehensive methodological validation to ensure the scientific validity and compliance of our methods. We provide one-stop, full-cycle project management, from sample receipt and experimental execution to report issuance, ensuring efficient response and smooth project progress.
We have established a complete quality system that complies with GMP and ALCOA+ principles, ensuring full traceability of the experimental process. Through professional multi-level data auditing and a robust deviation control (CAPA) mechanism, we fundamentally guarantee data integrity and high-quality project delivery.
We stay up-to-date with global regulatory updates, leveraging cutting-edge technology platforms, rigorous quality systems, and a team of experienced experts to provide comprehensive viral safety solutions for your biopharmaceuticals. We safeguard innovation with science and ensure safety with professionalism.
For testing solutions or detailed interpretations of methodological differences in pharmacopoeias of various countries, please feel free to contact us.