Human Cell Line Activation Test (h-CLAT) (OECD TG 442E)

With the development of reliable in chemico/in vitro assays, manufacturers and formulators are now able to determine whether or not a substance is a skin sensitizing agent without the need for animal testing. Each of the available assays recapitulates some element of the adverse outcome pathway (AOP) associated with a skin sensitization response in humans. Using an integrated testing strategy that incorporates these approaches for identifying skin sensitization hazard risk (as outlined by the Globally Harmonized System of Classification and Labelling of Chemicals) ensures regulatory compliance as well as consumer safety and satisfaction.

Overview of Human Cell Line Activation Method

In humans, multiple exposures to a skin sensitizer may cause activation of the immune system’s dendritic cells. Activation of these cells in the body is evidenced by changes in surface molecules on the dendritic cells. This event is regarded as the third key event in the skin sensitization adverse outcome pathway and is modeled in the h-CLAT in vitro assay. The h-CLAT measures the expression of specific cell surface makers associated with maturation of dendritic cells (i.e., CD86, CD54) in a human monocytic leukemia cell line (THP-1 cells).

Cells are exposed to the test material for 24 hours before cell surface maker expression is evaluated by staining the markers with fluorochrome-tagged antibodies and quantifying positively-stained populations using flow cytometry. Sensitizers are identified by comparing the relative fluorescence intensity of cell populations exposed to the materials versus cells that were exposed to solvent/vehicle controls.

The h-CLAT must be used in conjunction with additional assays to confidently determine a substance’s safety and skin sensitization potential as some materials (such as metabolically-driven sensitizers) may not be suitable for this assay.

Our Capabilities

CPTSM uses state-of-the-art testing laboratories, including labs that specialize in Analytical, Clinical, and In-Vitro Toxicology testing. All of our testing facilities are at your disposal for evaluating skin sensitization potential.

In our highly experienced and specialized departments, we test a wide range of cosmetic and personal care products. Our experts offer our clients guidance on the best testing strategies to ensure consumer safety and satisfaction as well as regulatory compliance.

Our Departments

Based on the individual needs of our clients, we offer a wide range of support across various departments. Since initial product testing can be fairly complex in terms of a high-quality, safe and trusted product, our clients typically explore the benefits of numerous departments and areas of expertise, including:

  • Clinical — Efficacy trials can be performed for safety, consumer in-use, and to support claims such as ‘dermatologist-tested’ and ‘ophthalmologist-tested.’
  • In-Vitro Toxicology — Our In-Vitro Toxicology department assists clients when they are looking to perform non-animal (animal-free) toxicology testing.
  • Microbiology — Microbial contamination and preservative efficacy testing are key to cosmetic and OTC drug products.
  • Photobiology — From SPF and Water-Resistant claims to Photoallergy and Phototoxicity studies, CPT℠ is the world leader in sunscreen testing.
  • Analytical — From raw materials, product batch release, and stability shelf-life testing to “free-of” and low-level detection claims, our analytical department ensures that all requirements are met based on industry standards.
  • Consulting – Our consulting staff can perform GMP and GLP audits of your facilities or vendors, help create SOPs, develop testing programs, etc.

Get In Touch

Please Note: CPT℠ only performs testing for companies. We do not perform product testing for the general public.

CPT℠ is closed January 16, 2023 in observance of Martin Luther King, Jr. Day.
Normal business hours will resume on Tuesday, January 17th.