Intradermal skin test

Because of the lack of an effective secondary anti-rabbit IgE antibody, IgE ELISA and IgE dot blot are unavailable. Therefore, the allergenic activity of rSsCLP was preliminarily investigated by intradermal skin tests. Three New Zealand White rabbits were injected subcutaneously with 400 μg purified rSsCLP in 0.1ml PBS. The negative controls were: (i) 0.1 mL PBS; (ii) physiological saline, 0.9%, 0.1 mL; and (iii) 400 μg of purified empty expression vector (pET-32a (+) ) in 0.1 mL PBS. The positive control was histamine, 4 mg/mL, 0.1 mL. Skin reactions were observed in the following 30 min and defined as positive with the presence of a wheal and erythema.