Modulation of Langerhans cell surface antigen expression by recombinant cytokines T. Ishii, L. J. Walsh, G. J. Seymour, and R. N. Powell tmmunopathology Unit, Department of Social and Preventive Dentistry, Untverstty ot Queenstand, Brtsbane, Austratia Ishii T, Walsh LJ, Seymour GJ, Powell RN: Modulation of Langerhans cell surface antigen expression by recombinant cytokines. J Oral Pathol Med 1990; 19: 355-9. This study examined the influence of cytokines on surface antigen expression by gingival Langerhans cells (LC) in organ culture, interleukin-6 (IL-6) and tumor necrosis factor a (TNF-a) upregulated the expression of CDla, HLA-DR and HLA-DP antigens on LC, TNF-a, interleukin-4 (IL-4), and transforming growth factor p (TGF-P) suppressed CD29 expression, while other cytokines, including interleukin-3 and granulocyte-macrophage colony stimulating factor, were with- out effect. No cytokines induced CD3, CD4, CD23, CD25 or CD45 RA antigen expression in organ culture. Since TNF-a and IL-6 can be secreted by keratino- cytes, these molecules, together with interleukin-1, are likely to play a role in the local control of LC number and function within the epithelial milieu. Thus, alter- ations in cytokine secretion by keratinocytes may at least in part be responsible for variations in LC number and antigen expression which occur in oral mucosal disorders. Key words: antigens; cytokines; gingiva; Langerhans' cells. L. J. Walsh, Department ol Social and Preventive Dentistry, Dental School, Turbot Street, Brisbane Queensland 4000, Australia Accepted for publication May 25, 1990 Langerhans cells (LC) are a type of den- dritic cell (1) which inhabit stratified squamous epithelia. These cells are characterized phenotypically by immu- noreactivity for CD 1 a and major histo- compatibility complex (MHC) Class II glycoproteins (2, 3). LC function as an important component of the immune system of normal oral mucosa, as de- monstrated in vitro by the ability of oral mucosal LC to present antigen to T lymphocytes and stimulate allogeneie and syngeneic mixed leukocyte reac- tions (4, 5). Since LC are critically re- quired for the initiation of mucosal im- mune responses and immune surveil- lance (3, 6), variations in LC number and function bear clinical import. LC express numerous cell surface an- tigens which are important in the im- mune function of this cell type (summa- rized in Table 1). We have previously demonstrated that certain cytokines produced within the epithelial environ- ment modulate surface antigen expres- sion on gingival LC (reviewed in 19). LC precursors present within gingival epithelium express CDla antigen following exposure to interleukin-1 (IL- 1), whilst IL-1 inhibitors abrogate CDla expression. Interferon gamma (IFN-Y) induces first HLA-DR, then HLA-DQ, and finally CD4 antigen ex- pression on CDla-|-LC. These effects are inhibited by prostaglandin E,. Regu- latory loops likely exist for cytokines and antigens other than those described above. In this study, gingival organ cul- ture was used to examine the influence of reeombinant cytokines on LC and other cell types within gingival epitheli- um. The latter include cells with dendrit- ic morphology which express CD3 or CD45RA but not CDla antigens (16, 33). These cells are present in the epithe- lium in oral lichen planus but occur only rarely in normal oral mucosa (16, 33). In the present study, we examined the effects of cytokines on the expression of CD3 and CD45RA antigen whilst evaluating LC antigen expression within the same material. Material and methods Cytokfnes The following recombinant human cy- tokines were obtained from Genzyme (Boston, Massachusetts): interleukin-3 (IL-3), interIeukin-4 (IL-4), interleukin- 6 (IL-6), and granulocyte-macrophage colony stimulating factor (GM-CSF). Ultrapure transforming growth factor beta (TGF-P) was obtained from Flow Laboratories (Sydney, Australia), and recombinant tumor necrosis factor al- pha (TNF-a) was obtained from the National Institute for Biological Stan- dards and Control (London, U. K,). All cytokines were dissolved in phosphate buffered saline (PBS), pH 7.2 contain- ing 0.1% bovine serum albumin (BSA), and stored at -70°C until used. With the exception of IL-4, these cytokines may be secreted by keratinocytes (26, 27) and are therefore potential media- tors of LC antigen expression. Organ culture The method used was that previously described in detail (20), In brief, human gingival tissue was obtained during peri- odontal surgery. Patient consent to use tissue which would normally be discard- ed during surgery was obtained with the approval of the institutional ethics com- mittee. All tissue donors had undergone hygiene phase periodontal therapy to remove any deposits of dental plaque or calculus prior to surgery, Explants prepared from gingival tissue were cul- tured in the presence or absence of cy- tokines for 24 hr in RPMI 1640 culture medium containing 5% heat-inactivated human AB serum, L-glutamine (20 mM), penicillin (100 IU/ml), and strep- tomyin (100 |ig/ml). The medium was not replaced during the culture period. Medium in individual wells was en- riched with cytokines (or 0,1 % BSA as a control) at the commencement of cul-