Ultrastructural localization of 2,4-dinitrophenyl groups on draining lymph node cells of guinea pigs following skin painting with 2,4-dinitrochlorobenzene: I. Scanning immunoelectron microscopic studies

Oral and epicutaneous desensitization in urushiol contact dermatitis in guinea pigs sensitized by 2 methods of different sensitizing potency

This investigation was conducted to study the relationship between the different intensities of sensitization to urushiol induced by the maximization test method (MT) or by the ear-flank method (EF) in guinea pigs, and hyposensitization induced by repeated oral and/or epicutaneous administration of the allergen, and to compare the immune tolerance achieved between these routes of dosing. During the observation period of 10 weeks, both oral and epicutaneous administration produced hyposensitization to urushiol after weak sensitization by EF; however, only combined administrations via the oral and epicutaneous routes achieved hyposensitization after potent sensitization, while inadequate tolerance was induced by oral dosing and none by epicutaneous dosing. Thus, it is indicated that difficulty in establishing immune tolerance may increase with increasing intensity of primary sensitization, and that hyposensitizing potency tends to increase in the order epicutaneous, oral and combined (e.p.+p.o.) administrations of urushiol.

The distribution of 2,4-dinitrophenyl groups in guinea pigs following feeding of 2,4-dinitrochlorobenzene

An immunofluorescent technique using anti-DNP antibody was employed to investigate the distribution of 2,4-dinitrophenyl (DNP) groups in various tissues following the feeding of 125 mg/kg 2,4-dinitrochlorobenzene (DNCB)-ethanol to guinea pigs that had been starved for 1 day. DNP groups were detected in the areas corresponding to the cytoplasm and the cell membrane of the epithelium in the upper gastrointestinal tract as well as on the cells of mesenteric lymph nodes, Payer's patches, the spleen, and peripheral blood. These results are discussed in relation to the mechanism of tolerance induction produced by the feeding of haptens.