Inhibition of the Induction of Contact Hypersensitivity by a UV-Mediated Epidermal Cytokine

Thomas Schwarz, Agatha Urbanska, Fritz Gschnait, Thomas A. Luger
1986 Journal of Investigative Dermatology  
UVB ex posure (290-320 nm) of mi ce has been shown to ca use systemic suppression of contact h y persen sitivity (CHS) . B eca use UVB radiation hardl y pene trates the epidermis , epidermal cell s have been anti cipated to be the site of th e initia tion of im111unosuppression. Supernatants d erived from UV-irradiated BALB /c epidermal cell cultures and a keratinocyte cell line (Pam 212) were eva lu ated for the ability to induce suppression ofCHS after i. v. injection to BALB /c mi ce. Inj
more » ... LB /c mi ce. Inj ection of supernatants derived fr0111 UV -treate d epidermal cells and Pam 212 cell s significantly blocked induction but not elicitation of CHS. In contrast, i. v. app li cation of supernatants derived from unirradiated E xposure of mice to UVB radiation (290-320 nm) interferes with the induction of delayed . and contact hypersensitivity (CHS) to haptens that are injected or applied to distant unirradiated skin areas [1] [2] [3] [4] . Systemic UVB-induced immunosuppression has been shown to be associated with defe ctive function of antigen-presenting spleen cells [5 ,61 lead in g to the ge neration of antigenspecifi c suppressor T-cells [7,8J. The skin provides an optical barrier aga inst UV radiation and UVB irradi ation ca nnot directl y affect cells o utside the epidermis of mice . One may therefore speculate that epidermal cells (EC) rel ease, in addition to immunom o dulatin g cytokines such as epiderm al cell-derived th ymocyte-activatin g factor (ET AF) and EC-interleukin 3, o ther mediators that are res ponsible fo r UV-indu ced immun osuppression [9] [10] [11] . Thus the present stud y was perfo rmed to inves ti ga te whether keratinocytes after UV exposure ca n rel ease factor(s) that influence the C HS reaction to co mmon antigens. MATERIALS AND METHODS Epidermal Cells and Cell Lines Epidermal cell suspensions were prepared from BALB/c mouse ear skin as described [1 2 ]. Manuscript received Janu ary 29, 1986; acceptcd for publica tion March 20, 1986. Supported by Fonds dcs Biirgertllcisters der Bundcshauptstadt Wicn . Reprint requests to: Thomas Schwarz, M. D., Department of Dermatology, Hos pital Vicnn a-Lainz, Wolkersbcrgcnstrasse J, A-11 30 Vienn a, Austri a. Abbreviations: CHS: co nta ct hypersensi ti vity DNFB: 2,4-dinitro-I-Auorobenzene EC: epidermal cell ETAF: cpidermal cell-derived th ymocyte-activating factor HPLC: high-performan ce liquid chromatograph y PBS : phosphate-buffered sa line PG: prosta glandin cell s did not inhibit CHS. Usin g hig h-perform an ce liquid chromatography gel filtration this mediator was shown to be a low-molecular-weight protein (15-50 kD) . M o reover UV-me diated inhibitor produ ction seems to b e confined to epid e rmal cells since n eithe r P 388 macrophages nor L 929 fibroblasts released this inhibitory cytokine. The refore UV radiation may induce epidermal cells to produ ce an inhibitor of CHS which is distinct from prostaglandins and leukotrienes and may participate in the reg ulation of UVmediated local as well as systemic immunosuppression . J Invest D ermatol 87:289-291, 1986 Viability of ECs as determined by trypan blue exclusion was usually between 75-85%. In addition , a spontaneously transformed BALB/c-derived keratinocyte cell line (Pam 212), a murin e fibrobla st cell line (L 929) , and a murine macrophage cell lin e (P 388) were used [9]. UV Irradiation of Cell Cultures Cells were washed and resuspended at 1 X 10(' cells / ml in phosphate-buffered saline (PBS). Two-milliliter cell suspensions w ere placed in 40-mm pol ys tyren e Pctri dishes followed by a sin gle 8-min exposure (200 J / m~) of UV radiation usin g an Osram Vitalu x bulb (output: 0.04 W / m 2 ) emittin g a linea r spectrum between 300-600 nm with peak emissions at 310 and 390 nm . All 8-min exposure was chosen beca use previou s experim ents ha ve shown this dose to be the maximum which did not affect cell viability. Subsequently cells were washed 3 times in RPMI1 640 (G IB CO), resuspended in 2 ml RPMI 1640, and supern atants were harves ted 3-24 h after irradiation. Immedi atel y after harves t viability of cells was determin ed by trypan blue exclusion. Co ntrol supernatants were deri ved frol11 cell cultures treated identica ll y but not UV irradiated. In order to rule o ut the influence of prostag landins (PG) in the supern ata nts derived from UV-ex poscd cells, in some experiments cultures were trcatcd with indo meth acin (1 ILg/ ml , Sig ma, St. Lo uis, Missouri) before irradi ati on. ' Sensitization Experiments Four hundred mi croliters of supern ata nts were ad ministered to BALB/ c mice via tail vein injecti on. O n days 5 and 6 fo llowing injection, razo r-shaved abdo mcns were sensitized by paintin g with 25 ILl of 0.5% 2,4dinitro-l-fluo ro benzene (DNFB) solution (acetonc:olive oil, 1 :4). Five da ys later the dorsal surface of th c left ea r w as challen ged with 20 ILl 0.3% DNFB solution, the ri ght ear was trea ted with aceto ne/oli ve oil alone, and the deg ree of car thickness was measured with a spring-loaded micrometer (Mitutoyo, J apan). Contact hypersensitivity to DNFB waS determined as the amount of ea r swelling o f the challenged left ea r minus the thickness of the ri ght ea r and was designated as fj. ear swellin g and expressed in 0022-202X /86/S03.S0 Co pyri ght
doi:10.1111/1523-1747.ep12696708 pmid:3734477 fatcat:fkdnijibvfat3ibf6kxx4b4cau