Expression of IL-10 and TNF-inhibitor genes in lacrimal gland epithelial cells suppresses their ability to activate lymphocytes.

Purpose: To determine whether the expression of either interleukin-10 (IL-10) or tumor necrosis factor (TNF) inhibitor genes in transduced rabbit lacrimal gland epithelial cells suppresses lymphocyte proliferation in an autologous mixed cell reaction, an apparent in vitro model of autoimmune dacryoadenitis.

Methods: Purified lacrimal gland epithelial cells, transduced with an adenovirus vector carrying either viral IL-10 or TNF-inhibitor genes, were used to study their effects on the proliferation of autologous lymphocytes as monitored by 3H-thymidine incorporation in a mixed cell reaction. After transduction, both epithelial cells and lymphocytes were cultured separately for 2 days and then epithelial cells were irradiated. Equal numbers of both cell types were then cocultured together for 5 days. Cocultures were pulsed with 3H-thymidine and isotope incorporation was determined. Gene expression was detected by enzyme-linked immunosorbent assay and Western blots.

Results: Lymphocyte proliferation was stimulated by epithelial cells and 3H-thymidine incorporation was significantly greater in these cocultures than in controls. The proliferation was significantly diminished in the presence of transduced cells producing either IL-10 or TNF inhibitor.

Conclusions: Transduction of lacrimal gland epithelial cells with adenovirus vectors encoding for either IL-10 or TNF-inhibitor proteins leads to expression of functional proteins capable of suppressing lymphocyte proliferation. Thus, lacrimal gland epithelial cells are a plausible target for gene therapy methods meant to produce immunoregulatory proteins.