EFFECTS OF THE IMMUNOSUPPRESSIVE DIPEPTIDE L-LEUCYL-L-LEUCINE O-METHYL ESTER ON EPIDERMAL LANGERHANS CELLS

[摘要] Pretreatment of newborn human foreskin epidermal cells (EC) with L-leucyl-L-leucine methyl ester (Leu-Leu-OME) was found to dramatically inhibit their ability to serve as alloantigen-presenting cells in a primary, one-way, allogeneic mixed epidermal cell-lymphocyte reaction (MECLR) without significantly affecting EC viability. The Leu-Leu-OME - induced MECLR inhibition could not be accounted for by a cytotoxic effect on epidermal Langerhans cells (LC), the class II major histocompatibility (MHC) antigen-bearing EC type that is fully responsible for alloantigen presentation in a primary allogeneic MECLR. Pretreatment with Leu-Leu-OME was found to inhibit the culture-induced increase in surface expression of HLA-DR molecules on LC. These findings suggest that in addition to its cytotoxic effect on cells containing high levels of dipeptidyl peptidase 1, Leu-Leu-OME can also perturb alloantigen-presenting cells that are not killed by this agent by modulating HLA-D region antigen expression, perhaps through its capacity to neutralize acid compartments within cells. In addition, these studies support the notion that the culture-induced upregulation of class II MHC antigens on epidermal LC is functionally associated with the enchanced alloantigen-presenting capabilities that these cells display after short-term culture and suggest that newly synthesized class II antigens might be critical to the alloantigen-presenting cell capabilities of LC.

[发布日期] 1992-11-01

[效力级别]  Proceedings Paper