In vitro primary sensitization of hapten-specific T cells by cultured human epidermal Langerhans cells--a screening predictive assay for contact sensitizers.
BACKGROUND
The need to develop predictive tests which could identify potential allergens has been recognized for many years. There is as yet no accepted in vitro method for the assessment of contact sensitizers.


OBJECTIVE
We have tested the ability of a range of contact allergens to induce in vitro primary sensitization of autologous T cells.


METHODS
T-cell proliferation induced by haptens using 2-day cultured human Langerhans cells as antigen-presenting cell was assessed by 3H thymidine incorporation. Antigen specific stimulation was calculated as stimulation indexes.


RESULTS
Strong allergens induced in vitro a primary T-cell response in all (trinitrophenyl, TNP: 13/13) or in the majority (fluorescein isothiocyanate, FITC: 7/10) of experiments. An irritant, sodium dodecyl sulfate (SDS), failed to generate a significant T-cell proliferation in any of the experiments (0/10). We obtained a significant lymphoproliferative response to weak sensitizers only in a limited number of experiments: (coumarin: 1/12, citronellal: 0/10, hydroxycitronellal: 2/8). p-Phenylenediamine (PPDA), a prohapten and highly sensitizing chemical in vivo, generated primary sensitization in vitro in only one of six experiments, while Bandrowski's base (BB), a metabolization product of PPDA induced a significant T-cell response in all six experiments.


CONCLUSIONS
The present in vitro model allows discrimination between two groups of substances: strong contact sensitizers (TNP, FITC, BB) on the one hand and weak sensitizers (coumarin, citronellal and hydroxycitronellal) and irritants (SDS) on the other hand. It could be used as a screening in vitro assay to eliminate strong contact allergens before further predictive animal tests have to be performed.
Krasteva
M
M
Laboratoire Peau Humaine et Immunité, INSERM U346, Hôpital E. Herriot, Lyon, France.
Peguet-Navarro
J
J
Moulon
C
C
Courtellemont
P
P
Redziniak
G
G
Schmitt
D
D
D003374:Coumarins / Q000276:immunology; D003877:Dermatitis, Contact / Q000276:immunology* / Q000517:prevention & control; D003979:Diazonium Compounds / Q000276:immunology; D016650:Fluorescein-5-isothiocyanate / Q000009:adverse effects; D006241:Haptens / Q000276:immunology*; D006801:Humans; D007114:Immunization; D007801:Langerhans Cells / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology; D010655:Phenylenediamines / Q000276:immunology; D011725:Pyridines / Q000276:immunology; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D013601:T-Lymphocytes / Q000276:immunology*; D013729:Terpenes / Q000276:immunology; D014301:Trinitrobenzenes / Q000276:immunology
D003374:Coumarins; D003979:Diazonium Compounds; D006241:Haptens; D010655:Phenylenediamines; D011725:Pyridines; D013729:Terpenes; D014301:Trinitrobenzenes; C056729:4-(2'-pyridyldithio)benzyldiazoacetate; C051597:Bandrowski's base; D012967:Sodium Dodecyl Sulfate; C020755:hydroxycitronellal; C030123:coumarin; D016650:Fluorescein-5-isothiocyanate