Appraisal of the sensitising potential of orally and dermally administered mercaptobenzothiazol by a biphasic protocol of the local lymph node assay

Mercaptobenzothiazole (MBT) is used while manufacturing natural rubber products. Our study deals with assessing its allergenic potential following dermal and oral routes of exposure, using a biphasic local lymph node assay (LLNA). Female Balb/c mice were treated with MBT (dermally 3, 10, 30% concentrations in DMSO; orally 1, 10, 100 mg/kg doses in corn oil) on the back (dermal study) or through oral administration (oral study) on days 1-3 followed by auricular application of 3, 10 and 30% concentrations, respectively, on days 15-17. End points determined on day 19 included ear thickness, ear punch weight, lymph node weight, lymph node cell count, and lymphocyte subpopulations (CD4+, CD8+, CD45+). After dermal application of 3% or 10% solution, a signiWcant increase in cell count and lymph node weight along with signiWcant decrease in CD8+ cells was observed. After initial oral administration of 1 mg/kg, we noticed a signiWcant ampliWcation in cell count. Following oral administration of 10 mg/kg, we observed a similar increase in cell count and lymph node weight. The results of our study show that the modiWed biphasic LLNA protocol can be used to study the sensitising potential of a compound also following the oralroute of exposure.