Delayed type hypersensitivity, sensitization or maximization studies may be employed to determine if the test article is a dermal sensitizer and if it can suppress an induced DTH reaction. Often called type IV hypersensitivity, DTH reactions are caused by the release of mediators from activated T cells, which in turn activate local endothelial cells and cause swelling and inflammation.

CBI offers expertise in the following DTH studies:

  • Skin sensitization (maximization) study using the Beuhler or Magnusson-Kligman method
  • Delayed type hypersensitivity study:
    • Oxazolone (TH-2 mediated; back skin or ear thickness) The oxalazone-induced delayed type hypersensitivity model (DTH) in the BalbC mouse is a robust and reproducible model for the assessment of T-cell mediated Type 4 immune response. The DTH is induced initially by applying oxalazone to the ear following epicutaneous sensitization.
    • TH-1 mediated hapten-induced: DNFB, DNCB, TNFB, TNCB, TMA, etc.
    • Back skin or ear thickness
  • Intradermal methylated BSA
  • Murine local lymph node assay for assessment of allergic contact dermatitis potential
  • Passive cutaneous anaphylaxis
  • Chemical irritant dermatitis

Endpoints for DTH studies may include:

  • Dermal optical coherence tomography (OCT)
  • Enzyme-linked immune absorbent assays
  • Immunohistochemistry assays
  • Laser Doppler for blood flow
  • Silhouette photography
  • Pharmacokinetic/pharmacodynamic sampling
  • Clinical chemistry
  • Histopathology by our in-house histology lab