Pel-Freez now offers pooled and single donor lyophilized human complement. We have made lyophilized rabbit complement for years; this applies the same process to our native and antibody-depleted human complement, so you get a freeze-dried product that keeps its activity without the frozen storage and dry-ice shipping.
If you already use our liquid antibody-depleted human complement, or buy it elsewhere, here is what changes with the lyophilized version.
What lyophilization does for you
Freeze-drying removes at least 95% of the water from the serum, which stops the degradation that makes liquid complement so fragile. Three practical things follow from that.
Shipping gets simpler, because liquid complement has to travel on dry ice under strict temperature control. The lyophilized product ships on standard cool packs, with fewer carrier restrictions, and it takes up less space in your freezer when it arrives.
Storage gets easier too: lyophilized complement is stable in a standard laboratory freezer at −20 °C; it does not need the −70 °C ultra-low freezer that liquid complement does. Activity holds over long storage and the product tolerates transport and temperature swings far better.
You also control the concentration, since reconstituting in less than the labeled volume gives you a more concentrated complement, so you can hit the activity your protocol needs without extra dilution steps, and use one product across several assays.
Quality testing
Like our liquid human complement, the lyophilized products are sourced from consenting donors at FDA-licensed centers in the United States. Each donor unit is screened for pathogens per FDA guidelines, with non-reactive or negative results for every test performed.
In processing we filter the complement through a 0.2 micron filter, verify complement activity (CH50), and confirm a final moisture content below 5% by gravimetric testing. Antibody-depleted lyophilized complement also goes through HPLC testing for residual immunoglobulin. Our pooled triple-depleted human complement, for example, contains less than 3.5% residual IgG, less than 3.5% IgM and less than 3.5% IgA.
Reconstituting and storing it
Bring the vial to room temperature, then add sterile water equal to the volume on the product label for a 1:1 reconstitution. Using less water than the label volume raises the potency, which is handy for applications that need more complement activity. Either way, test the reconstituted complement under your own assay conditions before you rely on the dilution.
To avoid clumping, let the powder dissolve gradually or invert the vial gently rather than stirring or vortexing straight away.
Once reconstituted, split anything you will not use immediately into small aliquots and store them at −70 °C. Hydrated complement is very heat-sensitive, so thaw on ice or in a cold water bath, never refreeze a thawed aliquot, and discard what is left after use.
Lyophilization is not new to us
We have supplied freeze-dried biological reagents for vaccine R&D, in vitro diagnostics and other biopharma and life science work for years, and we offer custom lyophilization services up to 250 L per batch.
“Pel-Freez's IgG/IgM depleted human complement has been essential for complement-dependent bactericidal assays in my lab. The material is of the highest quality, with minimal lot-to-lot variation. This reagent has saved us considerable time and expense. Pel-Freez's human complement will be invaluable for any lab or company developing vaccines that rely on complement activation for efficacy.”
Dr. Sanjay Ram, Professor, University of Massachusetts Medical School
Explore the lyophilized complement products, or contact us if you would like to trial a vial against your current liquid lot.