DERMAL AND AIRWAY RESPONSES TO MONOCLONAL-ANTIBODIES SPECIFIC FOR CANINE IGE

In order to understand mechanisms underlying variability of IgE-mediat ed responses in vivo, we compared effects of different monoclonal anti bodies to IgE on dermal and airway responses in a group of atopic dogs . Using intradermal testing, fourteen antibodies were screened in Base nji-Greyhound dogs. For further comparisons between dermal and airway responses, we selected the two antibodies that stimulated the greatest and least dermal responses. respectively. These antibodies bound to I gE with similar affinities (4.1 +/- 0.2 . 10(9) and 1.5 +/- 0.2 . 10(1 0) M-1). Dose-response curves to intradermal testing were constructed for these two antibodies. On a separate occasion, peripheral airway re sistance (Rp) was determined before and after aerosol challenge with a n antibody or saline in the same dogs. For one antibody (affinity 4.1 +/- 0.2 10 M-1), Rp reached a maximum (407 +/- 142% above baseline; me an +/- SE, n=6) 10 to 15 min after challenge, while maximum responses to saline (62+/-16% above baseline, p<0.01) occurred immediately after aerosol delivery. Responses to the other antibody were similar (p=0.0 68) to responses to saline. The magnitude of skin responses did not pr edict the magnitude of airway responses. These findings suggest that d ifferences in affinities, alone, do not predict magnitude of responsiv eness to the anti-IgE antibody and that mechanisms underlying skin and airway responses may differ qualitatively and/or quantitatively. (C) 1997 Elsevier Science B.V.