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Langerhans cell alterations in cutaneous carcinogenesis
H K Muller1, G W Dandie, S J Ragg
1Department of Pathology, University of Tasmania, Hobart, Australia.
In Vivo (Athens, Greece)
|May 1, 1993
Summary
Complete chemical carcinogens and tumor promoters, but not initiators, alter epidermal Langerhans cells (LC), impairing skin immunity and allowing early skin cancer cells to proliferate unchecked.
Area of Science:
- Immunology
- Dermatology
- Carcinogenesis
Background:
- Epidermal Langerhans cells (LC) play a crucial role in skin immune responses.
- Alterations in LC function are implicated in the early stages of skin cancer development.
Purpose of the Study:
- To investigate the effects of chemical carcinogens, tumor promoters, and initiators on epidermal Langerhans cells during early skin carcinogenesis.
- To understand the impact of these alterations on local skin immunity and immune tolerance.
Main Methods:
- Experimental application of carcinogens (DMBA, benzo(a)pyrene), tumor promoters (TPA), and initiators (urethane) to mouse and sheep skin.
- Analysis of epidermal Langerhans cell depletion, functional changes, and migration patterns.
- Assessment of immune responses, including T cell generation and anergy.
Main Results:
- Complete carcinogens and tumor promoters, but not initiators, depleted or altered epidermal Langerhans cells (LC) in mice.
- LC depletion in mice led to immune tolerance or anergy due to impaired antigen presentation.
- DMBA application in sheep caused LC depletion via increased migration from the skin; initiators and benzo(a)pyrene did not.
- Carcinogen handling as an antigen by LC may partially explain DMBA-induced migration, but not its prolonged nature.
Conclusions:
- Early-stage skin carcinogenesis involves altered immune function due to Langerhans cell depletion or modification.
- These immune alterations permit the proliferation of aberrant cells, evading immune surveillance and destruction.