Alterations in Lectin Binding to the Epidermis Following Treatment with 8-Methoxypsoralen Plus Long-Wave Ultraviolet Radiation

The alterations in lectin fluorescence stainings to the epidermis were examined in guinea pig skin treated with topical application of a 1% 8-methoxypsoralen (8MOP) solution plus long-wave ultraviolet (UVA) radiation (1.5–3.5 J/cm2) (PUVA). Serial biopsy specimens taken up to 21 days postirradiation were stained with 8 commercially available lectins labeled with either fluorescein isothiocyanate (FITC) or biotin (followed by avidin D-FITC): Bandeiraea simplicifolia agglutinin I (BSA), concanavalin A (Con-A), Dolichos biflorus agglutinin (DBA), peanut agglutinin (PNA), Ricinus communis agglutinin I (RCA), soybean agglutinin (SBA), Ulex europeus agglutinin I (UEA), and wheat germ agglutinin (WGA). In normal guinea pig skin UEA staining was absent. Following PUVA treatment, UEA and DBA stainings became apparent or stronger in intensity after days 7–14 (UEA) and days 4–7 (DBA), respectively, and returned to negative or weak by days 14–21. Stainings with Con-A, SBA, and WGA gave remarkable decreases in intensity after days 2–4 and recovered to the baseline by days 7–14. Intensity of BSA, PNA, and RCA stainings was decreased to a lesser degree than the other lectins. Such changes were not produced by application of 8-MOP, UVA radiation (