Expression of B7-1 costimulatory molecules in patients with multibacillary leprosy and reactional states
CLINICAL AND EXPERIMENTAL DERMATOLOGY
Authors: Santos, D. O.; Castro, H. C.; Bourguignon, S. C.; Bastos, O. M.; Rodrigues, C. R.; Van Heuverswyn, H.; Nery, J. A.; Miranda, A.
Abstract
Background. The expression of B7 as a costimulatory molecule on the surface of antigen-presenting cells such as macrophages and on dendritic cells characterizes the efficiency of the cell-mediated immune response. Aims. Our purpose was to evaluate B7-1 expression in peripheral blood mononuclear cells (PBMCs) immediately after cell isolation ('spontaneous' B7 expression), and in inflammatory cells from cutaneous lesions of patients with multibacillary leprosy (MB-L) without and during the reactional states of erythema nodosum leprosum (ENL) or reversal reaction (RR). Methods. Peripheral blood samples and skin biopsies of eight patients without (MB-L) and with reactional episodes (ENL and RR) were studied using antibodies against B7-1, CD1b, DR and CD14 in flow-cytometry and immunohistochemistry experiments. Results. The flow-cytometry studies (mean +/- SD% of fluorescent cells) revealed significant B7-1 expression on PBMCs isolated from patients with ENL (8.0 +/- 0.6%) and RR (15.0 +/- 1.4%) compared with that observed for patients with MB-L (0.4 +/- 0.2%). Similar results were observed for cutaneous lesions of these patients by immunohistochemical assays. One patient studied before and during ENL revealed weak B7 expression before the reactional episode (0.3% of cells) compared with the marked level of B7-expressing cells detected during ENL (8.5% fluorescent cells). Interestingly, an even higher B7 expression (15% of cells) was observed in patients with RR. Conclusions. Our results strongly suggest that B7 expression precedes reactional episodes in MB-L, which could be related to the acquisition of effective immunity to Mycobacterium leprae during reactional episodes in leprosy. We propose B7 expression as a marker of CMI response in reactional episodes in leprosy.
CCH cells are potent stimulators in the allogeneic mixed leucocyte reaction
VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY
Authors: Baines, S. J.; Blacklaws, B. A.; McInnes, E.; McConnell, I. M.
Abstract
Canine cutaneous histiocytoma (CCH) has been identified as a tumour of epidermal Langerhans cells (LCs) on the basis of immunophenotypic studies. Neoplastic Langerhans cells (CCH-LCs) were isolated from lesions of canine cutaneous histiocytoma. The CCH-LC cells expressed CD1b, CD11/18, CD45, MHC-I, and MHC-II. The CCH-LC cells were potent stimulators of the mixed leucocyte reaction (MLR) in vitro when compared to PBMCs from the tumour-bearing animals. This provides evidence that the neoplastic cells in CCH have functional as well as immunophenotypic characteristics of Langerhans cells. (C) 2007 Published by Elsevier B.V.
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