The Hapten in Contact Hypersensitivity to Dinitrochlorobenzene: Immunoelectron Microscopic and Immunofluorescent Studies

Abstract

Six hours after challenge with dinitrochlorobenzene (DNCB) in sensitized volunteers, infrequent cells reacting with both OKT6 (CD 1a) and with an antibody to DNCB were demonstrated in the upper dermis in 3 out of 4 subjects, using a double fluorescence technique. Single marker studies using polyclonal and monoclonal antibodies to DNCB showed cytoplasmic reactivity with peripheral accentuation in keratinocytes throughout the epidermis, most intense in the granular and basal layers, and occasional positive cells in the papillary dermis. Immunoperoxidase electron microscopy using polyclonal and monoclonal antibodies to DNCB demonstrated reactivity on keratinocyte and Langerhans cell membranes, with intracellular deposition of reaction product on mitochondria. Reaction product was present on the external leaflets of Birbeck granules, suggesting that the penetration of DNCB was passive rather than due to an active endocytic process. The immunofluorescent studies suggest that the double-fluorescing upper dermal cells were Langerhans cells but this could not be confirmed by electron microscopy.

Caged Fluorescent Haptens Reveal the Generation of Cryptic Epitopes in Allergic Contact Dermatitis

“…Also, because of the lipid composition of the basal cell membrane (Hachisuka et al, 1990), it has a relatively high fluidity, facilitating cell penetration and reaction with intracellular free thiols, forming HPCs. This distribution correspond to that observed in skin biopsies obtained from human volunteers exposed to 1-chloro-2,4-dinitrobenzene, a very potent thiol-reactive hapten (EC3 ¼ 0.05% (w/v; Gawkrodger et al, 1989;Kimber et al, 2002)).…”

Sensitization via Healthy Skin Programs Th2 Responses in Individuals with Atopic Dermatitis

“…Consequently, tracking T-cell sensitization to DNCB gives a unique view of the initiation of immune responses generated by percutaneous antigen exposure in humans. DNCB is a lowmolecular-weight (202 Da) highly lipophilic molecule that penetrates the skin efficiently independent of skin structural barrier function (Gawkrodger et al, 1989;Falconer et al, 1992;Tsai et al, 2001). Equivalent penetration of DNCB at the sensitizing dose in AD and controls is critical to this study; therefore, we first set out to confirm this assumption.…”

“…Skin penetration studies were undertaken as described previously (Gawkrodger et al, 1989;Franz et al, 2009). Briefly, DNCB (20 mg cm À 2 ) in vehicle (acetone) was applied to the epidermal surface at 33% of the clinically used sensitizing dose to increase the possibility of identifying small differences in penetration.…”

Η Αντιφλεγμονωδης Δραση Των Ιοντων Μαγνησιου Στην Αλλεργικη Δερματιτιδα Εξ Επαφης

“…To (83,181). Προφανώς η απορρόφηση απτενίων όπως το DNCB είναι παθητική διαδικασία και όχι ενεργητική πρόσληψη από την κυτταρική μεμβράνη (83).…”

“…To (83,181). Προφανώς η απορρόφηση απτενίων όπως το DNCB είναι παθητική διαδικασία και όχι ενεργητική πρόσληψη από την κυτταρική μεμβράνη (83). Στα μεν κερατινοκύτταρα εναποτίθεται στα μιτοχόνδρια ενώ στα κύτταρα Langerhans εντοπίζεται στα κοκκία Birbeck από τα οποία υπάρχει ένδειξη ότι απορροφάται με ενεργό μηχανισμό (165).…”