Lymphocyte function-associated antigen-1 is required for maximum elicitation of allergic contact dermatitis.

Cell adhesion molecules (CAMs) are known to play an important role in cell-mediated immunity and inflammation. To investigate the importance of one of the CAMs, lymphocyte function-associated antigen-1 (LFA-1) in allergic contact dermatitis (ACD), a specific anti-LFA-1 monoclonal antibody was injected into the ears of mice after sensitization but prior to challenge with dinitrofluorobenzene (DNFB). BALB/c mice were sensitized on the dorsal skin with DNFB, and challenged on the ears 6 days later. The effect of the antibody on the elicitation phase of contact sensitization was determined by its intradermal injection into the pinnae of the mice at doses of 1-40 micrograms. At 24 and 48 h after challenge, ear swelling was dose-dependently suppressed by injection of LFA-1 antibody at doses of 2-40 micrograms, which are less than 10% of the systemic dose required for effective suppression of delayed-type hypersensitivity in previous studies. Maximal inhibition of ear swelling (44%) was observed after injection of 20 micrograms of anti-LFA-1 antibody. Inhibition of ear swelling was accompanied by a reduction in dermal oedema and leucocyte infiltration into the dermis. Our results suggest that LFA-1 plays a significant role in the elicitation of ACD reactions, and also that our test system is a sensitive and useful means of evaluating the blocking effect of antibody to adhesion molecules thought to be involved in the elicitation phase of ACD.