Immune responses to biomaterials
Hypersensitivity
Delayed Hypersensitivity
- Reactions due to T cell - Ag interaction
- Ag is often a small hapten (e.g. metals) that combines with host carrier proteins
- Initial exposure results in little if any symptoms
- Hapten-protein complex stimulates production of T cells specific to allergen (memory)
- Subsequent exposure: T cells rapidly proliferate and release proinflammatory mediators (IL-2, IFN)
- Skin rash, eczema, ulcers
- Poison ivy, Ni, Cr, quinones, hair products, PMMA, silicones, latex