Response to cutaneous immunization with low-molecular-weight subunit keyhole limpet hemocyanin.

Background: This study was carried out to determine whether humoral and cellular immune responses would be provoked by cutaneous administration of keyhole limpet hemocyanin (KLH) and in particular by scarification of the skin (SS).

Methods: This was an unblinded, single-center, 8-week pilot study in healthy young adults. Twenty-four subjects assigned to 4 groups completed the study. Each group was immunized twice, with a 3-week interval, either by SS or intradermally (ID), with an SS dose of 50 or 250 μg and an ID dose of 100 or 250 μg. Serum was collected for antibody assays at baseline and 3 weeks after both the first and second immunizations. Delayed-type hypersensitivity (DTH) testing was performed before the first immunization and 3 weeks after the second.

Results: In the 250-μg SS group, there was a significant increase from day 0 to day 47 in anti-KLH IgG (p = 0.02; day 0: 3.46 ± 5.49 mg/dl, day 47: 7.54 ± 8.87 mg/dl) and anti-KLH IgA (p = 0.04; day 0: 4.78 ± 9.15 mg/dl, day 47: 11.42 ± 13.62 mg/dl). One subject in each treatment group showed a positive DTH test result representing 20% (50-μg SS), 10% (250-μg SS), 25% (100-μg ID) and 20% (250-μg ID) of the subjects.

Conclusions: It was possible to induce both humoral and cellular immune responses by SS administration despite the limited antigenic potency of the low-molecular-weight KLH preparation. This approach may be useful for studying the mechanisms of immune response in allergic skin diseases such as atopic dermatitis.