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DIETARY VITAMIN A ENHANCES SENSITIVITY OF THE LOCAL LYMPH NODE ASSAY
Citation:
Sailstad, D., S. Krishman, J. Tepper, D.L. Doerfler, AND M. Selgrade. DIETARY VITAMIN A ENHANCES SENSITIVITY OF THE LOCAL LYMPH NODE ASSAY. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-95/307.
Description:
Murine assays such as the mouse ear swelling test (MEST) and the local lymph node assay (LLNA) are popular alternatives to guinea pig models for the identification of contact sensitizers, yet there has been concern over the effectiveness of these assays to detect weak and moderate sensitizers. uch work has been done to improve the sensitivity of the MEST, including the addition of a vitamin A acetate (VAA) enriched diet, which increases its sensitivity. itamin A acetate has been reported to increase the numbers of Langerhans cells (antigen presenting cells) in the skin, which could in turn enhance the cellular immune response. ecause the LLNA relies on tritiated-thymidine incorporation by proliferating T-cells during the induction phase, we have studied the potential of the VAA diet to enhance sensitivity of the LLNA. esults indicate that the V -AA enriched diet significantly increased the LLNA sensitivity to formalin, eugenol, glutaraldehyde, trimellitic anhydride, and an azo dye at concentrations where no proliferation was observed in mice maintained on the standard diet. aintenance on a VAA diet for three weeks prior to initiating the sensitization procedure was optimal. hus, incorporation of a VAA diet improves the sensitivity of the LLNA as a quick, objective, and relatively inexpensive screen for detecting moderate and weak contact sensitizers.