Increased cell proliferation in spleen and lymph nodes peripheral to contact allergen application site.
Chipinda-I; Anderson-SE; Butterworth-LF; Beezhold-DH; Siegel-PD
Toxicologist 2009 Mar; 108(1):314
The local lymph node assay (LLNA) is widely used to identify chemicals that are contact sensitizers. The assay involves dosing mice with the chemical on both ears and pooling the cervical lymph nodes for assessment of lymphocyte proliferation as a marker of sensitization. The present study explored potential reduction in animal usage by dosing one ear with the allergen and the other with vehicle only. The respective draining lymph nodes were processed separately for quantification of cell proliferation. Cell proliferation in axillary and renal nodes, and in the spleen was also assessed. Cross contamination of the chemicals from the dosed ears to other parts of the body via preening was prevented by dosing restrained animals and washing off the residual chemical with saline after 4 hours. Dosing the left ear with 0.02% oxazolone (OX) on unrestrained animals resulted in marked cell proliferation in its draining lymph node (Stimulation index, SI = 12.8) and in the lymph node draining the contra-lateral vehicle dosed ear (SI = 6), and the axillary lymph nodes (SI = 3.3). Increased tritiated thymidine (3H-TdR) incorporation was not observed in the renal lymph nodes (SI = 1.1). Similar stimulation of cells was observed in the lymph node draining the ear contra-lateral to the allergen dosed ear when 30% hexylcinnamaldehyde (HCA) was applied. Increased proliferative activity was observed in non-directly draining lymph nodes of restrained mice demonstrating that these results can not be attributed to cross-contamination of adjacent skin. A significant increase in proliferation of splenocytes was observed. It is concluded that epicutaneous application of a contact allergen, as exemplified by OX and HCA, may induce cell proliferation in the neighboring lymph nodes and spleen indicative of hapten and/or haptenated proteins diffusing through the skin to peripheral nodes and the blood to produce systemic sensitization. Thus the node draining the contra-lateral ear can not be used as a control for application of contact allergen to a single ear in a modified LLNA.
Animal-studies; Biological-effects; Biological-factors; Biological-monitoring; Blood-cells; Blood-sampling; Cell-biology; Cell-damage; Cell-function; Cell-growth; Cell-metabolism; Cellular-function; Cellular-reactions; Chemical-analysis; Chemical-composition; Chemical-hypersensitivity; Chemical-reactions; Ear-disorders; Ears; Laboratory-animals; Laboratory-testing; Lymph-nodes; Lymphatic-system; Physical-reactions; Risk-analysis; Skin; Skin-absorption; Skin-exposure; Skin-sensitivity; Spleen-disorders; Splenic-tissue; Biomarkers; Blood-analysis; Blood-stream; Quantitative-analysis; Dose-response; Sensitization
The Toxicologist. Society of Toxicology 48th Annual Meeting and ToxExpo, March 15-19, 2009, Baltimore, Maryland