title: Modification and expulsion of keratins by human epidermal keratinocytes upon hapten exposure in vitro.
abstract: Allergic contact dermatitis is the most prevalent form of human immunotoxicity. It is caused by reactive low molecular weight chemicals, that is, haptens, coming in contact with the skin where hapten-peptide complexes are formed, activating the immune system. By using sensitizing fluorescent thiol-reactive haptens, that is, bromobimanes, we show how keratinocytes respond to hapten exposure in vitro and reveal, for the first time in a living system, an exact site of haptenation. Rapid internalization and reaction of haptens with keratin filaments were visualized. Subsequently, keratinocytes respond in vitro to hapten exposure by release of membrane blebs, which contain haptenated keratins 5 and 14. Particularly, cysteine 54 of K5 was found to be a specific target. A mechanism is proposed where neoepitopes, otherwise hidden from the immune system, are released after hapten exposure via keratinocyte blebbing. The observed expulsion of modified keratins by keratinocytes in vitro might play a role during hapten sensitization in vivo and should be subject to further investigations.
authors.affiliation: Department of Physics, University of Gothenburg, Gothenburg, Sweden. brigitte.bauer@physics.gu.se
authors.forename: Brigitte
authors.initials: B
authors.lastname: Bauer
authors.forename: Sofia I
authors.initials: SI
authors.lastname: Andersson
authors.forename: Anna-Lena
authors.initials: AL
authors.lastname: Stenfeldt
authors.forename: Carl
authors.initials: C
authors.lastname: Simonsson
authors.forename: Joorgen
authors.initials: J
authors.lastname: Bergstroom
authors.forename: Marica B
authors.initials: MB
authors.lastname: Ericson
authors.forename: Charlotte A
authors.initials: CA
authors.lastname: Jonsson
authors.forename: Kerstin S
authors.initials: KS
authors.lastname: Broo
mesh_terms: D001643:Bridged Bicyclo Compounds / Q000276:immunology; D002460:Cell Line; D017449:Dermatitis, Allergic Contact / Q000276:immunology*; D000078404:Epidermal Cells; D006241:Haptens / Q000276:immunology*; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000276:immunology*; D007633:Keratins / Q000276:immunology*
chemical_list: D001643:Bridged Bicyclo Compounds; D006241:Haptens; D007633:Keratins; C028381:monobromobimane