Contact sensitivity (allergic contact dermatitis) to bis(tri-n-butyltin) oxide in mice

Contact sensitivity (allergic contact dermatitis) to bis(tri-n-butyltin) oxide (TBTO) was demonstrated in the mouse. TBTO (in an acetone:olive olive oil vehicle) or acetone:olive oil alone (as a control) were applied to the shaved flank under an occlusive patch and animals were challenged on the dorsum of the ear 6 days later. Ear swelling was then measured using an engineer's micrometer, 2, 24, 48 or 72 h thereafter. Significant differences in ear swelling between control and TBTO-sensitized animals were found 24 h after challenge: thereafter the elicitation reaction declined rapidly whilst irritant swelling in control animals increased. Maximal elicitation of TBTO sensitivity could only be elicited by concentrations of TBTO that caused irritation. In a separate experiment, a single application of TBTO to the ears of naive animals provoked increase in auricular lymph node weight, cell yield and proliferation of lymph node cells during overnight culture. These data support the conclusion that TBTO is a contact sensitizer and illustrate the potential usefulness of the quantitative methods of contact sensitivity assessment which have been developed in the mouse.