When people think of laboratory mice, many picture the classic “white lab mouse.” But the mice used in modern biomedical research are far more than just any mouse grabbed for an experiment — and the most common, most widely used category is the SPF-grade mouse.
1. What does “SPF” mean?
SPF stands for Specific Pathogen Free, meaning “free of specific pathogens.” More precisely, an SPF-grade mouse is not free of all microorganisms; rather, it does not carry the specific pathogenic microorganisms and parasites that national standards designate as being highly harmful to animal health or clearly capable of interfering with scientific research.
This is the most easily confused point: SPF mice are not the same as germ-free mice. Germ-free mice must have no detectable microorganisms either inside or outside the body, whereas SPF mice only need to be free of the specific pathogens on the regulated list. The control standard for germ-free animals is generally stricter.
China’s current standard, GB 14922—2022 Laboratory Animals — Microbiological and Parasitological Grades and Monitoring, divides laboratory animal microbial control into three grades: conventional, SPF, and germ-free.
2. Why use SPF mice instead of conventional mice?
Because latent infections can quietly alter the immune system, inflammatory responses, tumor growth, or drug metabolism. Using SPF-grade mice makes the animal background more uniform, experimental data more stable, and results across different laboratories easier to compare.
3. What kind of environment do SPF-grade mice live in?
SPF-grade mice are typically housed in a barrier environment, commonly using individually ventilated cages (IVCs). Air is passed through high-efficiency filtration, and feed, water, bedding, and any items entering the barrier undergo corresponding treatment. Personnel generally must change clothes, change shoes, or wear dedicated protective suits and pass through air showers before entry.
This is not about keeping the mice “fastidiously clean,” but about:
- Reducing the entry of external pathogens
- Maintaining a stable microbial background in the animals
- Minimizing the interference of environmental fluctuations on experiments
- Ensuring greater comparability of results across batches and laboratories
GB 14925—2023 Laboratory Animals — Environment and Facilities sets requirements for temperature, humidity, ventilation, pressure differentials, air cleanliness, ammonia concentration, and noise in barrier environments.
4. VeloGene Biotechnology: Quality Backed by the MingCeler Laboratory Animal Center
VeloGene Biotechnology, a wholly-owned subsidiary of Guangzhou MingCeler Biotech, generates its custom mouse models in the high-standard facilities of the parent company. The MingCeler Laboratory Animal Research Center operates on a barrier-plus-IVC model. The barrier area is equipped with a quarantine room, a clean item receiving room, a clean item storage room, an operating room, and multiple independent housing rooms. The quarantine room, operating room, and housing rooms are all furnished with laminar flow hoods to ensure aseptic operating conditions. For biocontainment, standard operating procedures covering personnel access, item entry, animal handling, facility and equipment management, and early-warning mechanisms have been implemented, with staff training and strict assessment. Most non-autoclavable items are sent to a dedicated irradiation company for sterilization. An annual animal quality monitoring plan has been established, along with clear requirements for animal entry qualification.