About Bacterial Toxins

Bacterial toxins have been used over a wide range of applications based on their unique properties.  Cholera toxin B subunit and a pertussis toxin mutant can be used as vaccine carrier proteins or adjuvants to promote stronger immune responses to target polysaccharides or peptides in order to improve vaccine efficacy.  More notably, botulinum neurotoxins have been extensively used in clinical studies for many different benefits from cosmetic to treating hyperhidrosis or migraines.

List Biological Laboratories has extensive experience in producing custom GMP bacterial products for our clients, particularly but not limited to GMP botulinum neurotoxins.  We are a premier GMP Contract Manufacturing Organization (CMO), manufacturing products for both Phase 1 and Phase 2 clinical trials.  For over 2 decades, we have gained experience in developing scalable purification processes to produce GMP product that is compliant with GMP regulations.  The product is purified from pure cell culture using the most stringently tested reagents, packaged, then, per client request, lyophilized for storage.  Any of our current products can be produced as GMP, but List Labs also can develop purification plans for any bacterial protein of your choice.

Background on Bacterial toxins

Toxins produced by bacteria are typically of high molecular weight and have antigenic and enzymatic properties.  Bacterial toxins promote infection and disease by directly damaging host tissues and by disabling the immune system. Some bacterial toxins, such as Botulinum neurotoxins, are the most potent natural toxins known.  Other examples of toxins include Tetanus toxin produced by Clostridium tetani which leads to a fatal condition known as tetanus in many vertebrates (including humans) and invertebrates or Staphylococcal entertoxin B which is responsible for food poisoning in humans.  List Labs has experience with the production of a wide variety of toxins including:

  • Alpha Toxin
  • Botulinum Toxin
  • C. difficile Toxin
  • Cholera Toxin
  • Clostridial Toxins
  • Epsilon Toxin
  • Pasteurella Multocida Toxin
  • Pertussis Toxin
  • Shiga Toxin
  • Staphylococcal Entertoxin Type B
  • Tetanus Toxin

Process Development

List Labs is flexible to meet the unique needs of bacterial toxin customer projects.  We offer the following development services to establish a reproducible, streamlined, and robust process:

  • Media Optimization
  • Fermentation Development
  • Purification Development
  • Lyophilization Development
  • Analytical Method Development
  • Process Scale Up

Initially, a technical transfer is desired to acquire familiarity with the protein and process and replicate the customer’s data and results.  Small scale work is designed with the goal of a seamless transition toward a process that will support the large-scale manufacturing process, compliant to cGMP.  Optimization of liquid chromatography conditions frequently guarantees an increased yield and purity of the product.

To support process development and future process validation, in-process tests, that provide relevant information, aid in the evaluation of the success of each step. Test methods for a variety of evaluations are currently in use, from activity testing to immunoassays to ensure efficacy and confirm the quantity of the target protein.

In order to preserve the bacterial toxin or protein, lyophilization, or freeze drying, is typically requested.  List Labs has used this process to successfully preserve products for more than forty years. For lyophilization, the purified protein is buffer exchanged then sterile filtered in the desired formulation solution.  A robust quantitation method ensures accurate dosing of the product into vials. The lyophilization process involves a series of well-designed steps that include freezing, vacuum, and a series of temperature raising steps that result in a dry product with high activity. Several formulations can be tested simultaneously, allowing for rapid development.  At List Labs we have the experience to design these processes and the analytical tools to determine if the cycle is successful.

Analytical method development is an important aspect to the success of your project. Projects will require analyses specific to the desired product as well as generally applicable analyses described in the USP. These tests may include moisture, water activity, pH, osmolality, endotoxin content as well as specific activity of the target protein. We can apply our experience with product testing to develop the necessary analytics.


Our highly skilled team has extensive experience with cGMP manufacturing of bacterial toxin products from a broad range of genera, including strict anaerobe species.  Our expertly designed manufacturing suites provide containment in ISO7 or ISO8 suites.  In addition, we have multiple suites allowing parallel cGMP manufacturing activities streamlining project timelines and avoiding delays.

List Labs has several large scale options for fermentation and purification of your product including a 100 L stainless steel vessel with validated cleaning procedures and 40 L disposal bioreactors.  The product is then purified from the culture filtrate using a wide variety of available processes as needed.  The final purifed product is buffer exchanged into the final formulation solution by tangential flow filtration prior to formulation and lyophilization.  Our lyophilization capabilities include three Lyophilizers with a 5 tray or 3000 2 mL vial capacity each.  We offer the following manufacturing services:

  • Fermentation
  • Purification by Liquid Chromatography
  • Protein Precipitation
  • Nucleic Acid Digestion
  • Buffer Exchange
  • Protein Nicking
  • Formulation and Lyophilization
  • Packaging
  • Fill/Finish for Liquid Products

Equipment in our laboratory for manufacturing bacterial toxins include AKTA FPLCs and tangental flow filtration equipment of various sizes.  For more information about our available equipment, click the icon below.


List Labs staff has over 25 years’ experience manufacturing bacterial based novel drug substances and products.  List maintains several Drug Master Files with FDA and Health Canada and provides support to clients for IND filings.  As required by the State of California, List Labs maintains a current Drug Manufacturing License and CDC Select Agent registration enabling us to produce drug substance and drug products for our clients.

List Labs has manufactured a variety of bacterial toxins and proteins, live biotherapeutics products (LBS), and polysaccharides for our clients.  cGMP manufacturing has included both drug substance and drug products for Phase I and II clinical trials.

List complies with 21 CFR 210, 211, as well as ICH and Regulatory Guidelines, as applicable, for early stage Investigational New Drugs (IND) and Investigational Medicinal Products (IMP).

For more information, see our GMP services page.