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Direct Ni2+ antigen formation on cultured human dendritic cells
L T Van Den Broeke1, L C Heffler, M Tengvall Linder
1Department of Occupational Medicine, Dermatology Division, National Institute for Working Life; Department of Laboratory Medicine, Division of Clinical Immunology, Karolinska Institute and Hospital, Stockholm, Sweden.
Immunology
|May 8, 1999
Summary
Nickel allergy involves direct antigen formation on antigen-presenting cells (APCs). Mature dendritic cells (DCs) pulsed with nickel (Ni2+) activated allergic lymphocytes, suggesting Ni2+ reactivity is key.
Area of Science:
- Immunology
- Dermatology
- Toxicology
Background:
- Nickel (Ni2+) allergy is a common contact hypersensitivity.
- Antigen-presenting cells (APCs), such as dendritic cells (DCs), play a crucial role in initiating immune responses.
- The precise mechanism of Ni2+ antigen presentation remains incompletely understood.
Purpose of the Study:
- To investigate the direct antigen formation of Ni2+ on human dendritic cells (DCs).
- To assess the capacity of Ni2+-pulsed DCs to activate nickel-reactive lymphocytes in allergic individuals.
Main Methods:
- Human peripheral blood mononuclear cells (PBMCs) from Ni2+-allergic subjects and non-allergic controls were used.
- Immature and mature DCs were generated in vitro.
- DCs were pulsed with Ni2+ and co-cultured with autologous PBMCs to measure lymphocyte proliferation.
Main Results:
- Allergic subjects showed increased in vitro PBMC responses to Ni2+.
- Immature DCs pulsed with Ni2+ activated lymphocytes in some allergic subjects.
- Mature Ni2+-pulsed DCs significantly stimulated PBMC proliferation in allergic subjects, but not in controls.
Conclusions:
- Direct formation of the Ni2+ antigenic determinant on APCs is possible.
- Ni2+ uptake and processing may not be the primary mechanism in Ni2+ allergy.
- Lymphocyte activation differences may relate to the presentation of Ni2+-reactive groups on human leucocyte antigen (HLA) class-II molecules.