IgE reactivity and allergenic activity of rDer p 18.

<p>(A) IgE levels (y-axis: ISU ISAC standardized units) specific for a panel of HDM allergens (x-axis: Der p 1, Der p 2, Der p 5, Der p 7, Der p 10, Der p 11, Der p 14, Der p 15, Der p 18, Der p 21 and Der p 23) in HDM-allergic patients. (B) Dot-blotted rDer p 2, rDer p 18 and BSA were tested for IgE reactivity with sera from 7 HDM-allergic patients positive to rDer p 18 (#92–98), serum of a non-allergic person (NC) and with buffer (BC). Bound IgE Abs were detected with ¹²⁵I-labeled anti-human IgE Abs and visualized by autoradiography. (C) Up-regulation of CD203c expression was determined by FACS analysis after incubation of basophils from 4 HDM-allergic patients (#92–95) with increasing concentrations of rDer p 2 or rDer p 18 (x-axes) and displayed as stimulation index on the y-axes. (D) Recombinant Der p 18, rDer p 2, rDer p 23 and BSA were dotted onto nitrocellulose strips and incubated with sera from Der p 18-positive patients (#99, #100). Bound IgE antibodies were detected with ¹²⁵I-labeled anti-human antibodies and visualized by autoradiography. (E) Inhibition of IgE reactivity to blotted nDer p 18 by rDer p 18. Nitrocellulose-blotted <i>D</i>. <i>pteronyssinus</i> extract was incubated with sera from Der p 18-sensitized patients (#99 and #100), which had been pre-incubated with rDer p 18, or for control purposes, with BSA. Molecular weights (kDa) were shown at the margins.