title: Differential immunological effects of infrared irradiation and its associated heat in vivo.
abstract: Infrared irradiation (IR) is the most abundant fraction of sunlight reaching the earth's surface and provides heat. The fever response of an animal is known to regulate its immune responses. However, the non-thermal immune responses of IR were difficult to assess owing to its close association with heat. We hypothesized that IR irradiation induced differential immunological responses, independent of its associated heat. With an IR machine coupled with a delicate temperature control system, we investigated the non-thermal immunological effects of IR in vivo. With heating at 37 °C or 39 °C using an electric blanket or IR irradiation, we measured the skin's physiological parameters, including transepidermal water loss (TEWL), pH, skin hydration, elasticity, sebum production, and skin blood flow. We also measured the number of Langerhans cells in epidermal sheets and draining lymph nodes. Lymph node cells were activated by anti-CD3 antibody and their production of interleukin (IL)-5, 10, 13, 17, and interferon (IFN)-γ was measured by enzyme-linked immunosorbent assay (ELISA). The result showed that compared to heating alone, IR causes an enhanced activation of epidermal Langerhans cells, both in epidermal sheets and in draining lymph nodes. The activation of draining lymph node cells by anti-CD3 antibody in vitro induces both Th2 and Th1, but not Treg immune responses. Interestingly, IL-13, a Th2 cytokine, is induced the most. In contrast, physiological parameters and barrier functions of skin were not altered after IR irradiation. The study showed that IR alone without heat modulates immune responses in vivo, indicating that IR irradiation might regulate host immunity in a heat-independent manner.
authors.affiliation: Department of Dermatology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Chih-Hung
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Department of Dermatology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan; Department of Dermatology, National Yang Ming University, Taipei, Taiwan.
authors.forename: Chien-Hui
authors.initials: CH
authors.lastname: Hong
authors.affiliation: Department of Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Wei-Ting
authors.initials: WT
authors.lastname: Liao
authors.affiliation: National Institute of Environmental Health Sciences, National Health Research Institutes, Zhunan, Taiwan; Department of Dermatology, Kaohsiung Medical University and Hospital, Kaohsiung, Taiwan. Electronic address: dermyu@nhri.org.tw.
authors.forename: Hsin-Su
authors.initials: HS
authors.lastname: Yu
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology / Q000494:pharmacology; D017252:CD3 Complex / Q000276:immunology; D016207:Cytokines / Q000032:analysis / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007259:Infrared Rays; D007801:Langerhans Cells / Q000276:immunology / Q000528:radiation effects; D008198:Lymph Nodes / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects; D051379:Mice; D008810:Mice, Inbred C57BL; D012867:Skin / Q000737:chemistry / Q000276:immunology / Q000528:radiation effects*; D012881:Skin Temperature / Q000528:radiation effects; D018417:Th1 Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D018418:Th2 Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D014867:Water / Q000737:chemistry
chemical_list: D000906:Antibodies; D017252:CD3 Complex; D016207:Cytokines; D014867:Water
keywords: Epicutaneous sensitization; Heat; Infrared irradiations; T cell polarization