Transition metal sensing by Toll‐like receptor‐4: next to nickel, cobalt and palladium are potent human dendritic cell stimulators

Abstract

Given the adjuvant role of costimulatory danger signals, the development of contact allergies to the stimulatory metals may be facilitated by signals from direct TLR4 ligation, whereas other metal sensitizers, such as chromium, may rather depend on microbial or tissue-derived cofactors to induce clinical sensitization.

Dermatite de Contacto Alérgica em Idade Pediátrica: Estudo Retrospectivo

“…24 Os sais de cobalto e paládio, reativos simultaneamente com o níquel, tal como habitualmente descrito, podem coexistir em peças de bijutaria, relógios e adornos do vestuário e ligas metálicas usadas em material dentário e, sensibilizar o indivíduo de forma concomitante. Mas estes metais também desencadeiam a mesma resposta inata (ativação de Toll-like receptor-4 (TLR4) 28 e podem ser reconhecidos por receptores de células T (TCR) comuns (reações cruzadas). Foram relativamente raras as reações isoladas ao cobalto e crómio.…”

Possible implications of Ni(II) on oral IL-1β-induced inflammatory processes

“…Different authors analyzed Ni-induced mechanism in vitro and in vivo using several cell types (immune cells like dendritic cells (DCs) or monocytes, cancer cell lines or epithelial cells of the lung, dermis or gingival) various Ni(II) concentrations and analysis methods [5,[14][15][16][17][18][19][20]39]. In almost every cell line, Ni(II) induced dose-and time-dependent changes of proand anti-inflammatory cytokines or other mediators such as prostaglandins or MMPs [5,[14][15][16][17][18][19][20]39].…”

“…Thereby, biocompatibility is related to the duration and route of exposure, form and concentration of this metal. Several studies investigated the impact of Ni(II) on cell metabolism using immune cells like monocytes and dendritic cells (DCs) as well as human dermal or gingival epithelial cells [5,[14][15][16][17][18][19][20]. The authors detected dose-and time-depended cytotoxic and pro-inflammatory reactions.…”

A Perspective on the Challenges and Issues in Developing Biomarkers for Human Allergic Risk Assessments

“…Consequentially, the metabolite-hapten complex formation through human antigen presenting cells might also be unique. In devices that contain metals, nickel is a well-known human allergen with an allergic response prevalence estimated between 17 and 20% in the general population; but it is not an allergen in the mouse due to differences in Toll-like receptor 4 [23][24][25].…”