Now, it has been being accepted that reverse signaling through CD137 ligand (CD137L) plays an important role in vivo during hematopoiesis and in immune regulation. However, due to technical difficulty in dissecting both directional signaling events simultaneously in vivo, most biological activities caused by CD137-CD137L interactions are considered as results from signaling events of the CD137 receptor. To make the story more complex, CD137-/- and CD137L-/- mice have increased or decreased immune responses in a context-dependent manner. In this Mini review, I will try to provide a plausible explanation for how CD137L signaling is controlled during immune responses.
4-1BB Ligand* ; Animals ; Hematopoiesis ; Inflammation ; Mice

RT-PCR was used to clone DNA fragment of the extracellular domain of 4-1BBL from human THP-1 cells (human monocyte), and the expression vector pAYZ4-1BBL was constructed by cloning the extracellular domain of 4-1BBL into the expression vector pAYZ. The extracellular domain of 4-1BBL was expressed in E. coli 16C9 and purified by affinity chromatography. SDS-PAGE and Western blot analysis showed that the relativae molecular weight of soluble 4-1BBL is 22kD which was consistent with the theoretically predicted value. So far as we know, it is the first time that the soluble expression of 4-1BBL in E. coli was achieved 4-1BBL induced a significant release of IL-2 in stimulated Jurkat cells after 48h incubation, especially in the presence of tumor cell. At the same time the apoptosis level of Jurkat cell reduce more than 50%. In conclusion, 4-1BBL may be useful in cancer immunotherapy.
4-1BB Ligand ; biosynthesis ; genetics ; Apoptosis ; genetics ; Cell Line ; Cloning, Molecular ; Escherichia coli ; genetics ; metabolism ; Extracellular Space ; metabolism ; Humans ; Interleukin-2 ; biosynthesis ; Jurkat Cells ; Recombinant Proteins ; biosynthesis ; genetics

The main stream of CD137 studies has been directed to the function of CD137 in CD8+ T-cell immunity, including its anti-tumor activity, and paradoxically the immunosuppressive activity of CD137, which proves to be of a great therapeutic potential for animal models of a variety of autoimmune and inflammatory diseases. Recent studies, however, add complexes to the biology of CD137. Accumulating is evidence supporting that there exists a bidirectional signal transduction pathway for the CD137 receptor and its ligand (CD137L). CD137/CD137L interactions are involved in the network of hematopoietic and nonhematopoietic cells in addition to the well characterized antigen-presenting cell-T cell interactions. Signaling through CD137L plays a critical role in the differentiation of myeloid cells and their cellular activities, suggesting that CD137L signals trigger and sustain inflammation. The overall consequence might be that the amplified inflammation by CD137L enhances the T-cell activity together with CD137 signals by upregulating costimulatory molecules, MHC molecules, cell adhesion molecules, cytokines, and chemokines. Solving this outstanding issue is urgent and will have an important clinical implication.
4-1BB Ligand ; Biology ; Cell Adhesion Molecules ; Cell Communication ; Chemokines ; Cytokines ; Inflammation ; Models, Animal ; Myeloid Cells ; Rivers ; Signal Transduction ; T-Lymphocytes

BACKGROUND: Natural killer cells expanded from human peripheral blood (PB) have been used in cancer immunotherapy research. Although most research teams have access to human PB, it is necessary to find a source of blood that can be easily obtained. We have tested the possibility of using blood retained in a disposable platelet apheresis set as an alternative source, with special interest in expansion of NK cells for use in cancer immunotherapy research. METHODS: For expansion of NK cells, peripheral blood mononuclear cells (PBMCs) were isolated from an MCS+ platelet apheresis kit (Haemonetics, Braintree, USA) and PB from the same donor (n=7) and co-cultured with 100-Gy gamma ray-irradiated K562 cells expressing the 4-1BB ligand and membrane-bound IL-15 for three weeks in RPMI1640 medium in the presence of IL-2 and IL-15. Cytotoxicity was measured using WST-1 at 1:1, 2:1, and 4:1 effector-to-target (E:T) ratios for a period of four hours. RESULTS: Mean rate of expansion of NK cells was 1,097-fold and their purity was 94.4% from blood retained in a disposable platelet apheresis set; mean rate of expansion of NK cells was 953-fold and their purity was 92.0% from PB after a period of three weeks. No differences in cytotoxicity against K562, 697, Raji, and RPMI8226 were observed between NK cells expanded from two blood sources. CONCLUSION: Blood retained in a disposable platelet apheresis set is a useful and convenient source for expansion of NK cells for use in cancer immunotherapy research.
4-1BB Ligand ; Blood Component Removal ; Blood Platelets ; Humans ; Immunotherapy ; Interleukin-15 ; Interleukin-2 ; K562 Cells ; Killer Cells, Natural ; Tissue Donors

This study was purposed to investigate the molecular mechanism of 4-1BBL reverse signals in the human acute monocytic leukemia cell line of U937. The U937 cell line was used as target cells, and stimulated by the mouse anti-human 4-1BBL monoclonal antibody 1F1. The nuclear translocation of NF-κB and the co-location of 4-1BBL and CD28i molecules in U937 cells were observed with confocal laser scanning microscopy. The protein and m-RNA expression levels of 4-1BBL and CD28i were detected by flow cytometry and RT-PCR respectively. The results showed that the significant nuclear translocation of NF-κB and co-localization of 4-1BBL and CD28i on membrane of U937 cells appeared after being stimulated by mAb1F1. It is concluded that the 4-1BBL reverse signals transduction mediating the growth of U937 cells relates with the nuclear translocation of NF-κB. CD28i may be involved in intracellular 4-1BBL reverse signaling pathways.
4-1BB Ligand ; immunology ; metabolism ; Antibodies, Monoclonal ; pharmacology ; CD28 Antigens ; metabolism ; Coculture Techniques ; Humans ; NF-kappa B ; genetics ; Signal Transduction ; U937 Cells

OBJECTIVETo study the cytotoxic activity against tumor cells and cytokines production of spleen cells induced in vitro by murine 4-1BBL gene transfected Hepa1-6.

METHODSThe eukaryotic expression vector pCDNA3.1(+)-m4-1BBL was transfected into murine hepatocellular carcinoma cell line Hepa1-6 by Liposomes. Then the transfected cells were selected in medium containing G418 (400 - 800 micro g/ml) and termed as Hepa1-6-m4-1BBL. The TCV-m4-1BBL was obtained by treating them with mitomycin (MMC). Cocultivation TCV with syngeneic murine spleen cells, then the lymphocytes were tested for cytotoxic activity against Hepa1-6-wt cells and the supernatants were harvested for detecting the cytokines (IL-2, TNF-alpha and GM-CSF).

RESULTSHepa1-6-m4-1BBL cells expressed 4-1BBL protein with highest cell surface level. The 4-1BBL mRNA could still be detected in the cells when cultured 48 h after treated with MMC (80 mg/L). Comparing with TCV-Hepa1-6, the tumor cell vaccine derived from Hepa1-6-m4-1BBL (TCV-m4-1BBL) could induce a more efficient cytotoxic activity of syngeneic murine lymphocyte against its parental tumor cell Hepa1-6 (P < 0.05), but not against non-parental tumor cell H22 and NIH3T3. Higher levels of IL-2, TNF-alpha and GM-CSF were released by the splencytes after stimulated by TCV-m4-1BBL.

CONCLUSIONSThese results suggest the expression of m4-1BBL by tumor cells is effective in inducing antitumor immune responses.

4-1BB Ligand ; Animals ; Cancer Vaccines ; immunology ; Female ; In Vitro Techniques ; Liver Neoplasms, Experimental ; immunology ; Mice ; Mice, Inbred C57BL ; T-Lymphocytes, Cytotoxic ; immunology ; Transfection ; Tumor Necrosis Factors ; genetics ; physiology

OBJECTIVEThe non-specific antitumor immunity effect of 4-1BBL-B7-H3 gene was investigated by establishing an oral squamous cell carcinoma human peripheral blood lymphocyte-severe combined immunodeficient (SCID) mice chimeric model.

METHODSForty mice were randomly divided into five groups. All groups, except the non-immune reconstitution group (group D), had reconstructed human partial immune system. The control group (group A) was injected with Tca8113 cells. The Ad4-1BBL-B7-H3 group (group B) was injected with Tca8113 cells transfected by adenovirus containing 4-1BBL-B7-H3 gene. The empty vector group (group C) was injected with Tca8113 cells transfected by adenovirus containing an empty vector. The non-immune reconstitution group (group D) was injected with Tca8113 cells. The non-tumor group (group E) was injected with PBS. The tumor volumes in each group were measured weekly. Human IgG in blood was obtained through the tail vein and was determined by enzyme-linked immunosorbent assay. Human CD3+ and D56 lymphocytes were assessed by flow cytometry. Model animals were killed on the ninth week. Differences in the expression of the natural killer group 2 member D (NKG2D) and toll-like receptor 2 (TLR2) in tumor tissues of each group were observed by immunohistochemical method. 4-1BBL-B7-H3 gene expression in mice tumor tissues was detected by reverse transcription polymerase chain reaction (PCR) and the expressions of major histocompatibility complex 1 class related molecule (M1C) A, M1CB, and TLR2 were detected by real-time quantitative PCR.

RESULTSThe tumor volumes of group B were remarkably lower than those in the other groups (P < 0.05). Human IgG and CD3+ and CD56+ lymphocytes were detected in the peripheral blood of immune-reconstituted mice. These lymphocytes were remarkably higher in group B than those in groups A, C, and E (P < 0.05). Higher NKG2D and TLR2 expression were observed in group B tumor than those in the other groups. The stable expression of 4-1BBL-B7-H3 gene in group B was proven. The expression of M1CA, M1CB, and TLR2 were significantly higher in the group B tumor than those in groups A, C, and D (P < 0.05).

CONCLUSIONThe high 4-1BBL-B7-H3 gene expression in tumor tissues could successfully induce the proliferation of CD3+ and CD56+ lymphocytes. This expression can also directly or indirectly activate TLR2 and up-regulate the expression of NKG2D and its ligands (M1CA and M1CB), which result in an effective antitumor immune response.

4-1BB Ligand ; Adenoviridae ; Animals ; Carcinoma, Squamous Cell ; Disease Models, Animal ; Genetic Vectors ; Humans ; Mice ; Mice, SCID ; Mouth Neoplasms ; Neoplasms ; Transfection

OBJECTIVE: To study the expression of CD137L in laryngeal carcinoma, and to analyze its clinicopathological significance. METHOD: The expression of CD137L in 50 laryngeal carcinoma specimens and 9 normal laryngeal mucous tissues were detected by immunohistochemical staining. RESULT: The positive CD137L staining were found in all 50 cases of laryngeal carcinomas (100%), while its staining were negative in normal laryngeal mucous. There was significant difference between two groups (P < 0.01). The positive ratio of CD137L staining had no relationship with the factors such as age, sex and tumor site, while it had significant correlation with the pathological stage, T stage and lymph node metastasis. CONCLUSION The expression of CD137L might play an important role in the development of laryngeal carcinomas.
4-1BB Ligand ; metabolism ; Adult ; Aged ; Aged, 80 and over ; Carcinoma, Squamous Cell ; metabolism ; pathology ; Female ; Humans ; Laryngeal Neoplasms ; metabolism ; pathology ; Male ; Middle Aged ; Neoplasm Staging ; Prognosis

BACKGROUND: The ligand for CD137 (CD137L; also called 4-1BBL) is mainly expressed on activated APCs such as dendritic cells, B cells and macrophages. Even though CD137L functions as a trigger of the CD137 signaling pathway for T cell activation and expansion, engagement of CD137L can deliver a signal leading to the production of proinflammatory cytokines in macrophages. METHODS: We generated cell-permeable TAT-CD137L cytoplasmic domain fusion protein (TAT-CD137Lct) and examined its ability to initiate the CD137L reverse signaling pathway. RESULTS: Treatment of TAT-CD137Lct induced the production of high levels of IL-6 and TNF-alpha mRNAs and proteins in peritoneal macrophages. TAT-CD137Lct increased phosphorylation of Erk, p38 MAPK and Jnk, and activated transcription factors C/EBP and CREB. However, TAT-CD137Lct did not visibly affect the degradation of the inhibitor of NF-kB (IkBalpha). We further demonstrated that JNK activation was required for TAT-CD137Lct-induced production of TNF-alpha, while activation of Erk and p38 MAPK were involved in IL-6 and TNF-alpha production. CONCLUSION: Our results suggest that TAT-CD137Lct is an effective activator for the CD137L reverse signaling pathway.
4-1BB Ligand ; B-Lymphocytes ; Cytokines ; Cytoplasm ; Dendritic Cells ; Interleukin-6 ; Macrophages ; Macrophages, Peritoneal ; NF-kappa B ; p38 Mitogen-Activated Protein Kinases ; Phosphorylation ; Proteins ; RNA, Messenger ; Transcription Factors ; Tumor Necrosis Factor-alpha

Our previous study has demonstrated that there is a significant delay of Balb/c cardiac allograft rejection in the C57BL/6 4-1BB-deficient knockout recipient. In this study, we examined the effect of combined blockade of the 4-1BB and CD28 costimulatory pathways on cardiac allograft rejection in the C57BL/6-->Balb/c model. A long-term cardiac allograft survival was induced in CD28/4-1BB- deficient mice (>100 days survival in 3 of 4 mice), which was comparable with CD28-deficient mice (>100 days survival in 2 of 5 mice; P<0.2026). There was no long-term cardiac allograft survival in either wild-type (WT) or 4-1BB-deficient mice, even though 4-1BB-deficient recipients showed a significant delay of cardiac allograft rejection than WT mice. An in vitro mixed leukocyte reaction (MLR) assay showed that 4-1BB-deficient and WT mouse T cells had a similar responsiveness to allostimulation, whereas CD28- and CD28/4-1BB-deficient mouse T cells had a defective responsiveness to allostimulation. Furthermore, 4-1BB-deficient mice showed a similar CTL but an elevated Ab response against alloantigens as compared to WT mice, and the alloimmune responses of 4-1BB-deficient mice were abrogated in the CD28-deficient background. Overall, these results indicate that the CD28 costimulatory pathway plays a major role in the alloimmune response and that 4-1BB signals are dependent upon CD28 signals.
Transplantation, Homologous/immunology ; Signal Transduction/*immunology ; Mice, Knockout ; Mice ; Isoantigens/immunology ; Heart Transplantation/immunology ; Graft Survival/immunology ; Cytotoxicity Tests, Immunologic ; Antigens, CD28/genetics/*immunology/metabolism ; Antibodies/immunology ; Animals ; 4-1BB Ligand/deficiency/genetics/*immunology/metabolism