A type of rat hepatosplenic gamma-delta (gammadalta) T-cell lymphoma developed after injections with hepatocyte growth factor (HGF) oligonucleotides, which was rejected by surviving syngeneic spleen graft.

The transduction of exogenous hepatocyte growth factor (HGF) genes to spleen T lymphocytes and the immune effects of syngeneic spleen graft on spleen lymphoma cells were studied in LEW/Sea rats. Three different systems were designed. (1) Six female rats and six male rats received irradiated spleen graft and were followed for 7 months. (2) Five female rats and six male rats received intra-peritoneal (i.p.) injections of the Lewis red cells incorporated 20-bp HGF genes and anti-interleukin-6 (IL-6) antibody (Ab) with spleen graft and were followed for 5.5 months. (3) Four females and five males received i.p. injections of the Lewis red cells incorporated 20-bp HGF genes and anti-IL-6 Ab without spleen graft and were followed for 5.5 months. Hemato-pathological analyses, flow cytometer analyses of gamma-delta (gammadelta) T-cell receptor (TCR)-positive lymphocytes and reverse-transcription-polymerase chain reaction (RT-PCR) of TCRgamma gene, TCRValpha3 gene and apoptotic genes were performed. Results showed that one of the six females received irradiated spleen graft developed nodal gamma-delta (gammadelta) T-cell pre-lymphoma with 100% of gammadelta TCR+ lymphocytes in the mesenteric lymph nodes. One female injected with the HGF genes and anti-IL-6 Ab and grafted spleen died of advanced hepatosplenic gammadelta T-cell lymphoma at 3.5 month observation. All the five males injected with the HGF genes and anti-IL-6 Ab without spleen graft developed early hepatosplenic gammadelta T-cell lymphoma at 5.5 month observation. In two rats with spleen graft and the two rats without spleen graft, which were injected with the HGF genes and anti-IL-6 Ab, the lymphoma was suspected uncertainly with activated TCRValpha3 mRNA. The i.p. injections of HGF genes, which were incorporated in the red blood cells, triggered hapatosplenic gammadelta T-cell lymphoma. Surviving spleen graft rejected the lymphoma cells, but not in rats rejected the graft. Spleen graft was a good organ transplantation to expect graft versus lymphoma effects.