Induction of type IV hypersensitivity to contact allergens in guinea pigs by in vitro haptenized allogenic peritoneal exudate cells.

The induction of type IV hypersensitivity to contact allergens in guinea pigs has been studied by using allogenic peritoneal exudate cells (> 90% macrophages), which had been incubated primarily in vitro with dinitrochlorobenzene, formaldehyde, potassium dichromate, nickel II sulphate or para-aminobenzoic acid. In these guinea pig sensitization experiments Freund's complete adjuvant was used. In all haptens investigated the sensitization rates of the presented method were parallel to the known contact allergenicity in humans and, apart from the potassium dichromate results, comparable with those of the guinea pig maximization test. Because of its alternative immunization procedure, in which only few or no allergen molecules escape the effective presentation pathway, the authors conclude that this method could be developed into a predictive test assay for the evaluation of the contact allergenicity of water-soluble substances.

Impairment to viability of neutrophils and lymphocytes by angular psoralens and UV-radiation.

The angular psoralen derivative, 4,5'-dimethylangelicin (Dm Agn), both without and with UV-radiation induces under adequate conditions a higher percentage of lethally damaged cultured human polymorphonuclear neutrophils (PMN) as compared with angelicin (Agn). In general, PMN photosensitized with Dm Agn are less resistant than similarly photosensitized lymphocytes. These results suggest that Dm Agn might be used to improve the photochemo (PUVA-)therapy of skin diseases where PMN are of pathogenic importance.