Resumo

VILLARROEL DORREGO, Mariana; SPEIGHT, Paul M  e  BARRETT, A William. Expression of Major Histocompatibility Complex class II and costimulatory molecules in oral carcinomas in vitro. Med. oral patol. oral cir. bucal (Ed.impr.) [online]. 2005, vol.10, n.3, pp.188-195. ISSN 1698-4447.

Recognition in the 1980’s that keratinocytes can express class II molecules of the Major Histocompatibility Complex (MHC) first raised the possibility that these cells might have an immunological function, and may even act as antigen presenting cells (APC). For effective T lymphocyte activation, APC require, in addition to MHC II, appropriate costimulatory signals. The aim of this study was to determine the expression of MHC class II and the co-stimulatory molecules CD40, CD80 and CD86 in keratinocytes derived from healthy oral mucosa and oral carcinomas. Using flow cytometry, it was confirmed that oral keratinocytes "switch on" expression of MHC class II molecules after stimulation with IFN γ in vitro. All keratinocyte lines expressed CD40 constitutively; by contrast, CD80 and CD86 were universally absent. Loss of CD80 and CD86 may be one means whereby tumours escape immunological surveillance.

Palavras-chave : Costimulatory molecules; CD40; CD80; CD86; Major Histocompatibility Complex; oral epithelium; oral squamous cell carcinoma.

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