title: Use of proliferation tests to evaluate the effects of complexing agents on beryllium toxicity.
abstract: Occupational exposure to beryllium may cause chronic beryllium disease (CBD), a granulomatous interstitial pneumonitis caused by a cell-mediated immune response with delayed hypersensitivity initiated by an electrostatic interaction with the MHC class II human leukocyte antigen (HLA). Increased research efforts focus on the development of a CBD treatment by chelation therapy. This work presents an in vitro evaluation of the beneficial effects of beryllium chelation with different organic substrates. We have used a standard beryllium lymphocyte proliferation test (BeLPT) adapted for mouse splenocytes. Three complexing agents, 4,5-dihydroxy-1,3-benzenedisulfonic acid (tiron), nitrilotripropionic acid (NTP) and nitrilotriacetic acid (NTA), were tested using different protocols of the splenocyte proliferation test (SPT). We studied their corrective effect (beryllium pre-exposed splenocytes), their protective effect (ligand pre-exposed splenocytes) and their combined effects at fixed Be:L ratio of 1:2, at fixed Be concentration and at fixed L concentration. We also studied the effect of tiron in preventing splenocyte sensitization to beryllium. All three complexing agents showed a corrective effect and proved efficient in the combined effects, except NTA in the fixed Be:L ratio. Only NTP and tiron showed a significant protection at lower beryllium concentrations, while NTA was not significant. Splenocytes pre-exposed to chelated beryllium did not show sensitization while splenocytes pre-exposed to beryllium were sensitized. We observed a strong correlation between the efficiency of the complexing agent and its affinity towards beryllium. Both tiron and NTP showed a similar affinity towards the beryllium ion that is 10(7) higher than that of NTA.
authors.affiliation: Department of Chemistry, Université de Montréal, succ. Centre-Ville, Montréal, QC, Canada H3C 3J7.
authors.forename: Chadi H
authors.initials: CH
authors.lastname: Stephan
authors.forename: Sébastien
authors.initials: S
authors.lastname: Sauvé
authors.forename: Michel
authors.initials: M
authors.lastname: Fournier
authors.forename: Pauline
authors.initials: P
authors.lastname: Brousseau
mesh_terms: D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D001607:Berylliosis / Q000276:immunology* / Q000517:prevention & control; D001608:Beryllium / Q000737:chemistry / Q000633:toxicity*; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002614:Chelating Agents / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D009571:Nitrilotriacetic Acid / Q000737:chemistry / Q000494:pharmacology; D013154:Spleen / Q000187:drug effects* / Q000473:pathology
chemical_list: D002614:Chelating Agents; C020711:beryllium sulfate; D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt; D009571:Nitrilotriacetic Acid; D001608:Beryllium