Use of scale antibodies for the detection of antigens in psoriatic lesions.

Extractable IgG from psoriatic scale was purified, labelled with biotin and used in ELISA and immunofluorescence (IF) in an attempt to detect and localize prominent antigens in psoriatic scale extracts and in psoriatic lesions, respectively. Biotinylated immunoglobulins isolated from psoriatic scale from each of 5 patients were used. Scale extracts were fractionated on a Sephacryl S-300 column, and antigens detected by scale IgG were eluted in the void volume and at a Kav 0.55. The profile was very similar for each antibody preparation. Antigens recognized by serum IgGs from both healthy controls and psoriatic patients were detected in the void volume only. Antigens recognized by a rabbit antiserum against the psoriasis-associated antigen, pso p27 (6), were restricted to the fractions eluted at a Kav 0.55. Furthermore, the binding of scale IgG to the antigens eluted at Kav 0.55 was inhibited by purified pso p27 antigen. Two of the scale antibody preparations gave rise to a distinct fluorescence on skin biopsies from psoriatic lesions in indirect immunofluorescence. The antigens recognized were localized to a subfraction of dermal cells and in the endothelial lining of some of the dermal vessels. Double labelling with these scale antibodies and a rabbit anti-pso p27 antiserum showed that both antibody preparations bound to the same cells in the psoriatic lesions, while only a minority of these cells were recognized by a murine monoclonal antibody against human IgG. The observations described indicate that the pso p27 is a major antigen in the immune reactions in psoriasis.