What is Heat Inactivated FBS

What does heat inactivation remove?

Heat inactivation specifically destroys the complement system — a cascade of ~30 proteins in serum that collectively lyse foreign cells via the membrane attack complex (MAC). In cell culture, bovine complement can non-specifically lyse human cells (particularly lymphocytes and other immune cells) or interfere with virus neutralisation assays where complement-dependent neutralisation would add to antibody-dependent neutralisation.

When is HI-FBS needed?

• Embryo culture (IVF): HI-FBS at 5–10% is standard for bovine, equine and porcine embryo culture — complement activity can damage blastomeres
• PBMC and immune cell assays: Human lymphocytes are sensitive to bovine complement lysis — use HI-FBS or switch to human AB serum
• Virus neutralisation assays: Prevents complement-dependent neutralisation from confounding antibody-mediated neutralisation
• Mycoplasma-free culture: Heat inactivation does NOT kill mycoplasma — use PCR-tested FBS instead

When is HI-FBS NOT needed?

For routine mammalian cell line culture (HeLa, A549, CHO, HEK293, MCF-7), heat inactivation is unnecessary and slightly reduces growth-promoting activity. Standard FBS is preferred for general cell culture.

Key Facts

• Heat inactivation is performed at exactly 56°C for 30 minutes — higher temperatures or longer times denature albumin and growth factors, reducing biological activity
• The primary target is complement proteins (C1q, C3, C4, C5) — the classical complement cascade is heat-labile and inactivated at 56°C
• Heat inactivation does NOT remove: endotoxin, IgG, mycoplasma, viruses, growth factors (minor reduction), or albumin
• HI-FBS is standard for: embryo culture (bovine, equine, porcine IVF), PBMC assays, virus neutralisation assays, and any application where complement-mediated lysis of target cells would confound results
• Heat inactivation slightly reduces growth-promoting activity — some cell lines grow slower in HI-FBS vs standard FBS
• Not required for most routine cell culture — only use when complement activity is a documented problem for your specific assay

Further Reading

• What is FBS?
• Animal Reproduction & IVF Serum Guide
• FBS Portfolio — All Grades

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