TNF gene was transfected into murine LAK cells by retrovirus. Our results showed that TNF gene-transfected LAK cells secreted TNF more than normal LAK cells and control gehe-transfected LAK cells. The in vitro growth ability and cytotoxicity of TNF gene-transfected LAK cells were augmented significantly.The cytotoxicity of ,TNF gene-transfected LAK cells was markedly inhibited by anti - TNF monoclonal antibody, indicating that the, above augmentation was mediated by TNF secreted by transfected LAK cells. Significant therapeutic effect on the ascitic liver carcinoma.-bearing mice was achieved by i.p. injection of low dosage TNF gene transfected LAK cells and IL - 2.

Peripheral blood mononuclear cells (PBMNC) isolated from patients with acute leukemia (AL) and from normal controls were cultured in medium containing 1000 units/ml of recombinant interleukin 2 (IL-2). Marked LAK activity was induced on the third culture day in the normal controls,, with the highest cytotoxicity appearing between day 3 and 5 whereas induction of LAK activity in the AL patients began on the 5th day of culture, with the peak level appearing at day 15, showing that the peak of LAK activity was significantly delayed in AL. LAK cells surface phenotyping tests showed that CD8+ and CD16+ positive cells began to increase significantly from day 5 and reached the highest level at week 3, whereas CD4+ subclass began to decrease on day 5 and dropped to the nadir at week 3. The proportion of CD8+ and CD16+ cells were positively cor related with LAK activity, but, that of the CD4+ cell was inversely related with the LAK activity.

Human immunodeficiency virus type-I (HIV-I), one kind of lentiviruses, was characterized by a complex genome that encodes two regulatory proteins and four accessory proteins in addition to the common gag, pol and env gene products. So far, a few of different types of replication-defective vectors were constructed, the highest viral titer from one of which was above 10(7) TU/ml. Several studies on packaging cell line found that eliminating the four accessory genes would have few effect on transduction ability of vector and split-genome package system could reduce the possibility of producing replication-competent virus. There are two kinds of characters on HIV-I vectors. Firstly, it was highly efficient in transducing CD34(+) human hematopoietic stem/progenitor cells; secondly, repeated injections of the HIV-I vector into animal did not elicit the rejection response. HIV-I vector had an extensive host range.

Objective： To elucidate the role of bone marrow stromal cells in cooperation with exogenous cytokines in hematopoiesis. Methods： Fetal bone marrow stromal cells (FBMSC) was combined with cytokines including SCF,IL-3,IL-6,GM-CSF in a 5-day liquid culture system of adult bone marrow mononuclear cells, then we cultured bone marrow derived CD34+-enriched cells with FBMSC+SCF+IL-3+IL-6+G-CSF+EPO for 2 weeks. Results：FBMSC were in good cooperation with above mentioned exogenous cytokines. When CD34+-enriched cells from adult bone marrow were cultured with combinations of FBMSC, SCF, IL-3, IL-6, G-CSF and EPO, total nucleated cells, CFU-GM, BFU-E and CD34+ cells were increased by 119.6±30.9, 54.6±17.4, 25.2±4.4, 11.1±4.2 folds, respectively. Conclusion：FBMSC in cooperation with exogenous cytokines support the in vitro expansion of human hematopoietic progenitor cells efficiently.

Humans ; Lymphadenitis