Work with confidence when you choose complement prepared by Pel-Freez, the industry leader in baby rabbit complement for vaccine development and now a source for guinea pig complement, and antibody-depleted human complement produced using a proprietary Pel-Freez separation process.

With a focus on delivering consistently-performing products, we tightly control and monitor every step of the production process in our ISO 9001-certified facility. But biological variability means that sometimes a specific lot doesn’t work for your application. When that happens, we work closely with you to ensure that your project needs are met.

Complement Product Categories

Don’t see what you need? We can customize our offering, whether it’s species, product scale, or something else. Just contact us and let us know how we can help.

Antibody Depleted
Human Complement

Save time and ensure reliable results with consistently produced human complement—bulk amounts available.

Poly bottle of antibody depleted human complement

Baby Rabbit

Conduct a range of vaccine development assays with consistently produced baby rabbit complement.

Two containers of baby rabbit complement

Guinea Pig

Get expertly prepared guinea pig complement obtained from healthy animals.

Bottle of guinea pig complement


Keep your research moving with dependable purified immunoglobulins from Pel-Freez.


Vaccine Development

Well known and widely used in the vaccine industry, Pel-Freez enables a range of safety and efficacy assays including:

  • Opsonophagocytic killing assays (OPKA)
  • Serum bactericidal assays (SBA)
  • Complement-dependent cytotoxicity assays (CDC)

With the ability to deliver bulk scales of consistently-performing human, rabbit and guinea pig complement, we can spare your teams the hassle of doing the preparation, maximizing efficiency, productivity, and consistency.

Frequently Asked Questions

Should I use human, rabbit or guinea pig complement for my application?

The WHO has accepted rabbit complement for use in a variety of vaccine efficacy tests and in most cases is a suitable alternative to human complement. Now that Pel-Freez has developed a large scale commercial of source antibody depleted human complement however, we encourage new and existing vaccine development programs to evaluate this product for suitability in their assay systems. Guinea pig complement is also a viable option for highly potent complement function.

Is complement activity affected by the antibody removal process?

The antibody removal process can result in decreased complement potency in hemolytic titer assays, however, we have optimized our process to limit the extent of this decrease. Each lot of complement is tested using the complement hemolytic titer assay at 50% dilution to ensure adequate functional activity.

How does freezing and thawing affect complement activity?

Multiple freeze-thaw cycles will result in reduced complement potency therefore we offer a variety of pack sizes to satisfy applications ranging from small scale assay development experiments to large scale clinical studies. We recommend limiting the number of freeze-thaw cycles and sub-aliquot whenever possible in order to extend the shelf life of all of our complement products.