CD137 enhances cytotoxicity of CD3(+)CD56(+) cells and their capacities to induce CD4(+) Th1 responses.

CD137 (4-1BB) is a TNFR superfamily member that mediates the costimulatory signal resulting in T cells and NK cells proliferation and cytokines production, but the effects of CD137 signaling on CD3(+)CD56(+) cell subpopulation have not been well-documented. The aim of this study was to investigate the effects of CD137 signaling on regulation of CD3(+)CD56(+) cell function. Anti-CD137 mAb or mouse IgG1 isotype control was added to CIK cell culture to determine the effects of proliferation and anti-tumor effects on CD3(+)CD56(+) cells. We observed that anti-CD137 mAb could dramatically promote proliferation of CIK cells. And CD137-CIK cells and CD3(+)CD56(+) cell subpopulation within them possessed higher ability to kill tumor cell line A549. The SCID mice engrafted with A549 cells and treated with CD137-CIK cells have prolonged survival. Further studies revealed that the percentages of CD3(+)CD56(+) cells were elevated significantly in CD137-CIK cells. The expression of NKG2D was up-regulated on CD3(+)CD56(+) cells from CD137-CIK cells. The expression of IFN-gamma, IL-2 and TNF-alpha increased significantly whereas the production of TGF-beta(1), IL-4 and IL-10 decreased in CD3(+)CD56(+) cells from CD137-CIK cells. In addition, anti-CD137 mAb can elevate the capacity of CD3(+)CD56(+) cells to induce CD4(+) Th1 responses. We further showed that the anti-CD137 mAb also had the same effects on CD3(+)CD56(+) cells expanded from the PBMCs of patients with NSCLC. We concluded that CD137 signaling could enhance the abilities of CIK cells to kill tumor cells in vitro and in vivo via increasing the proportion of CD3(+)CD56(+) cells and their cytotoxicity. Furthermore, CD137 signaling can elevate the capacity of CD3(+)CD56(+) cells to induce CD4(+) Th1 responses which may enhance their anti-tumor activity indirectly. Taken together, our studies could be considered as valuable in CIK cells-based cancer immunotherapy.

[Establishment of human acute monocytic leukemia model in severe combined immunodeficient (SCID) mice and the analysis of pathological changes].

AIM: To establish a model of human M5 leukemia and investigate the pathomorphological change in severe combined immunodeficient (SCID) mice after being transplanted with SHI-1 cells. METHODS: Various dose of SHI-1 cells were transplanted i.p. into SCID mice. Serial tail vein samples at regular intervals were prepared for detecting the expression of CD14, CD137L on SHI-1 cells by flow cytometry (FCM). All dying mice were dissectted and the liver, spleen, kidney and bone marrow were examined to detect the appearance and distribution of the SHI-1 cells by FCM and/or immunohistochemistry. RESULTS: Tumors appeared in the abdomenion of the mice treated with various dose of SHI-1 cells. However, the dissemination of SHI-1 cells in murine tissues was found only in the groups of middle/high dose. SHI-1 cells were firstly found in tail vein samples 3 weeks after transplantation, and the time of engraftment was related to the dose of cells. CONCLUSION: The SHI-1/SCID mice was constructed, which provided a useful tool to investigate acute monocytic leukemia(AML).

A functional anti-human 4-1BB ligand monoclonal antibody that enhances proliferation of monocytes by reverse signaling of 4-1BBL.

4-1BB Ligand (4-1BBL), a transmembrane molecule, member of the tumor necrosis factor ligand superfamily, is an important costimulatory molecule in the immune response. In this study a functional anti-human 4-1BBL MAb 1F1 was obtained and the specificity of this MAb was verified by flow cytometry and Western blotting. This MAb effectively recognized the 4-1BBL molecule expressed on a series of malignant cell lines as well as on DC and monocytes and it inhibited the proliferation of T lymphocytes, costimulated by soluble 4-1BBL and agonist anti-human CD3 MAb. Furthermore, we demonstrated that MAb 1F1 induced an impressive proliferation of monocytes from peripheral blood by triggering the reverse signal through 4-1BBL. This functional anti-human 4-1BBL MAb provides a valuable tool for further study of biological functions as well as signal transduction of 4-1BBL/4-1BB.