Construction of CAR-T cells targeting CS1 and analysis of their antitumor activity in vitro / 生物工程学报

We constructed the CS1-targeted second- and third-generation CAR-T cells with genetic engineered 4-1BB or/and ICOS as a costimulatory signaling molecule by use of lentiviral platform. The CS1-targeted second-generation CAR-T cells with ICOS or 4-1BB had similar anti-neoplastic activity. When effector/target ratio was 1:1, the CAR-T cells with ICOS showed better killing effect on IM9-lucgfp cells than those with 4-1BB. However, The CS1-targeted third-generation CAR-T cells exihibited lower cytolytic capacity against IM9-lucgfp cells than the CS1-targeted second-generation CAR-T cells when the ratio of effector/target was 1:1, 2:1 or 5:1. When the ratio of effector/target was 10:1, the killing efficacy of both the second- and third-generation CAR-T cells against IM9-lucgfp cells was more than 85%, significantly higher than that of the control T cells. Taken together, both the CS1-targeted second- and third-generation CAR-T cells with ICOS or/and 4-1BB could efficiently kill CS1-positive multiple myeloma cells, but the CS1-targeted second-generation CAR-T cells had more potent killing effect on CS1-positive multiple myeloma cells than the CS1-targeted third-generation CAR-T cells.

Is CD137 Ligand (CD137L) Signaling a Fine Tuner of Immune Responses?

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.

Suppression of tumor growth induced by human 4-1BBL-B7-H3 gene in reconstructed immune function in severe combined immunodeficient mice / 华西口腔医学杂志

<p><b>OBJECTIVE</b>The 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.</p><p><b>METHODS</b>Forty 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.</p><p><b>RESULTS</b>The 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).</p><p><b>CONCLUSION</b>The 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.</p>

Anti-human 4-1BBL monoclonal antibody stimulates the nuclear translocation of NF-κB and the co-location of 4-1BBL/CD28 isoform in U937 cells / 中国实验血液学杂志

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.

The effect of CD137-CD137 ligand interaction on the expression of nuclear factor of activated T cells c1 in apolipoprotein E-deficient mice atherosclerotic plaque model / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the effects of CD137-CD137L interaction on the nuclear factor of activated T cells c1 (NFATc1) in apolipoprotein E knockout (ApoE(-/-)) mice.</p><p><b>METHODS</b>Atherosclerotic plaque model was produced by rapid perivascular carotid collar placement in ApoE(-/-) mice. In vivo, the expression of NFATc1 in mice plaque and lymphocytes was detected by immunohistochemical and flow cytometry, respectively. In vitro, the NFATc1 mRNA and protein expressions in cultured lymphocytes of ApoE(-/-) mice were measured by RT-PCR and flow cytometry, respectively.</p><p><b>RESULTS</b>In vivo, after stimulating CD137-CD137L signal pathway, the expression of NFATc1 was significantly upregulated in the atherosclerotic plaques and lymphocytes. In vitro, the mRNA and protein expressions of NFATc1 in cultured leukocytes of ApoE(-/-) mice were also significantly increased, the maximal effect appeared post 20 µg/ml anti-CD137 mAb-stimulation and reached maximum at 24 h at any concentrations. Anti-CD137L mAb significantly downregulated the mRNA and protein expressions of NFATc1 in lymphocytes of ApoE(-/-) mice, maximal effect appeared at 20 µg/ml anti-CD137L mAb and reached minimum at 24 h.</p><p><b>CONCLUSION</b>CD137-CD137L interactions can modulate the expression of NFATc1 in this ApoE(-/-) mice atherosclerotic plaque model.</p>

Ex vivo Expansion of Human Natural Killer Cells from Blood Retained in a Disposable Platelet Apheresis Set / 대한수혈학회지

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.

Recombinant TAT-CD137 Ligand Cytoplasmic Domain Fusion Protein Induces the Production of IL-6 and TNF-alpha in Peritoneal Macrophages

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.

Adjuvant effect of co-stimulatory molecule CD137L on cellular responses to HBsAg DNA vaccination in mice / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the adjuvant effect of co-stimulatory molecule CD137L on cellular responses to HBsAg DNA vaccination in mice.</p><p><b>METHODS</b>Eukaryotic expression vector containing the full length of mouse CD137L cDNA sequence (pcD137L) was transfected into NIH3T3 cells, and then the expression of CD137L mRNA and protein in the transfected cells were detected by RT-PCR, flow cytometry and immunofluorescence method, respectively. The BALB/c mice were co-immunized with pcD137L and HBsAg DNA vaccine (pcDS) by intramuscular injection. HBsAg-specific activity of splenic cytotoxic T lymphocyte (CTL) in the immunized mice was measured by LDH release assay. The splenic memory CD8+ T cells, and intracellular IFN-gamma and IL-4 of splenic lymphocytes and CD8+ T cells after immunization were detected by flow cytometry.</p><p><b>RESULTS</b>The NIH3T3 cells transfected with pcD137L efficiently expressed mouse CD137L mRNA and protein. HBsAg-specific CTL responses induced by the pcDS plus pcD137L group were much stronger than those induced by pcDS alone at a week after immunization (P<0.05). Compared to mice immunized with pcDS alone, CD44high and CD127(IL-7R) were all significantly up-regulated in memory CD8+ T cells from the mice immunized with pcDS combined CD137L both at a week and 12 weeks after immunization (P<0.05 and P<0.01). The pcDS plus CD137L group also elicited higher levels of IFN-gamma secreted by CD8+ T cells and splenic lymphocytes than pcDS alone at a week, 12 and 13 weeks after immunization, respectively (all P<0.01).</p><p><b>CONCLUSION</b>DNA, viral/immunol; Co-stimulatory molecule CD137L can enhance the Tc1 (type I) cell-mediated immunity, HBsAg-specific CTL and memory responses induced by HBsAg DNA vaccine, and may be an efficient adjuvant in priming HBV-specific T cell response.</p>

Prostate cancer cell vaccine transfected with 4-1BBL induces anti-tumor immunity in vitro / 中华男科学杂志

<p><b>OBJECTIVE</b>To explore the anti-tumor immunity in vitro induced by prostate cancer cell vaccine transfected with recombinant adenovirus encoding 4-1BBL in mice.</p><p><b>METHODS</b>The replication-deficient adenovirus AdEasy-1 system was used to construct recombinant adenovirus Ad-m4-1BBL and Ad-eGFP. The prostate cancer cell RM-1 of mice was transfected with Ad-m4-1BBL and Ad-eGFP, and treated with mitomycin (MMC) to produce TCV, TCV-Ad-eGFP and TCV-Ad-m4-1BBL, followed by co-culture with syngeneic murine spleen cells. Then the cytotoxic activity of the lymphocytes against RM-1 cells was analyzed with CCK-8 solution, and IL-2 and INF-gamma were detected by ELISA.</p><p><b>RESULTS</b>The 4-1BBL protein was highly expressed in the TCV-Ad-m4-1BBL of the 4-1BBL-transfected mice. TCV-Ad-m4-1BBL significantly increased the expressions of IL-2 ([180.24 +/- 2.22] pg/ml) and INF-gamma ([1512.46 +/- 23.64] pg/ml) as compared with TCV and TCV-Ad-eGFP (P < 0.05), and induced higher RM-1 cell specific cytotoxicity ([34.24 +/- 2.64]%) than the latter two ([9.82 +/- 1.48]%) and ([14.65 +/- 3. 21]%), (P < 0.05). But none of them exhibited significant cytotoxicity against hepatocellular carcinoma Hepal-6.</p><p><b>CONCLUSION</b>The m4-1BBL-expressing prostate cancer cell vaccine can effectively induce anti-tumor immune responses.</p>

Blockade of 4-1BB/4-1BB ligand interactions prevents acute rejection in rat liver transplantation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Blocking the 4-1BB/4-1BB ligand (4-1BBL) signal may modulate the secretion of Th1/Th2 cytokines and prolong the survival of the grafts, which play a key role in organ transplantation tolerance. The aim of this study was to investigate the role of blockade of the 4-1BB/4-1BBL co-stimulatory pathway with 4-1BBL monoclonal antibody (mAB) in acute rejection of rat orthotopic liver transplantation.</p><p><b>METHODS</b>The orthotopic liver transplantation model was set up, while male Lewis rats were used as liver donors and Brown-Norway rats as recipients. The recipient rats were intravenously injected with anti 4-1BBL mAB or isotype control antibody. Groups were monitored for graft survival after transplantation. Plasma chemistry, including aspartate transaminase (AST), alanine aminotransferase (ALT), and bilirubin (BIL), was assayed. The concentrations of interleukin (IL)-2, IL-10 and interferon (IFN)-gamma in plasma were also measured by enzyme-linked immunosorbent assay. Allograft histology images were collected under light microscope and electron microscope.</p><p><b>RESULTS</b>Isotype antibody treated recipients exhibited elevated plasma levels of liver injury markers including AST, ALT and BIL, progressive portal and venous inflammation and cellular infiltration of the liver allografts, and a mean graft survival time (MST) of 10.9 days. Administration of anti 4-1BBL mAB resulted in a decrease in plasma levels of liver injury markers and the concentrations of IL-2, IL-10 and IFN-gamma. The histological grade of rejection on day 7 decreased and MST (17.3 days) increased substantially.</p><p><b>CONCLUSIONS</b>These results demonstrate that attenuation of acute rejection follows the blockade of the 4-1BB/4-1BBL co-stimulatory pathway with 4-1BBL monoclonal antibody and strongly suggest it is a promising strategy to prevent progression of graft rejection by suppressing T cell-mediated immunity.</p>

Clinicopathological significance of CD137L expression in laryngeal carcinoma / 临床耳鼻咽喉头颈外科杂志

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.

Expression of co-stimulatory molecules in peripheral blood of patients with idiopathic thrombocytopenic purpura in relation with platelet antibodies / 中国实验血液学杂志

This study was aimed to detect the expression of co-stimulatory molecules CD80, CD86 and CD137 in peripheral blood of patients with idiopathic thrombocytopenic purpura (ITP), the content of platelet antibodies in serum (PAIgG), and to analyze the relationship between them and their correlation with the number of platelet in peripheral blood, so as to clarify the roles of co-stimulatory molecules in pathogenesis of idiopathic thrombocytopenic purpura and evaluation of disease status. The co-stimulatory molecules CD80, CD86 and CD137 in peripheral blood mononuclear cells (PBMNCs) of 48 ITP patients and 40 normal persons were detected by immunofluorescence and flow cytometry (FACS), PAIgG content in serum was detected by enzyme-linked immunosorbent assay (ELISA). The results showed that CD80, CD86 and CD137 expression levels in ITP patients were (4.92 +/- 2.02)%, (8.68 +/- 4.25)%, (5.32 +/- 2.67)% respectively, PAIgG content was 210 +/- 3.02 ng/10(7) PA, all these of which were significantly higher than these in normal control group (2.01 +/- 0.75)%, (4.56 +/- 2.06)%, (1.37 +/- 1.25)%, PAIgG 20 +/- 1.13 ng/10(7) PA (p < 0.01). Correlation of co-stimulatory molecule expression with PAIgG content were positive (r = 0.302, p < 0.05), but correlation of co-stimulatory molecule expression with platelet number was negative (r = -0.369, p < 0.05). It is concluded that the co-stimulatory molecules CD80, CD86 and CD137 are involved in immune response and the incidence of ITP. Their over-expression closely associates with the pathogenesis of ITP and clinical status, so that correcting the abnormal expression and regulating the immune status may be one therapeutic strategy and have important clinical significance.

Immunological killing effect of recombicant adenovirus vector rAD-mTERT-m4-1BBL on mouse hepatoma cell line Hepa1-6 cells co-cultured with T lymphocytes / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To study the immunological suppressing effect of recombinant adenovirus vector rAD-mTERT promotor-m4-1BBL (rAD-mTERT) on mouse hepatoma cell line Hepa1-6 cells in co-culture with T lymphocytes.</p><p><b>METHODS</b>Adding recombinant adenovirus rAD, rAD-CMV-m4-1BBL (rAD-CMV) and rAD-mTERT to Hepa1-6 and L929 cells, respectively, to observe the effect of these adenoviruses on growth and apoptosis of these cells in co-culture with T lymphocytes.</p><p><b>RESULTS</b>Adding adenovirus significantly suppressed the growth and slightly increased apoptosis of the two types of cells (P < 0.05). rAD-mTERT promotor-m4-1BBL showed only pro-apoptotic effect on Hepa1-6 cells. When co-cultured with T lymphocytes, rAD-CMV-m4-1BBL showed promoting effect on apoptosis of the cells. Compared with that of T cells pre-co-culture, CD4(+) and CD8(+) T cells were proliferated, and the ratio of CD4/CD8 was significantly reduced (from 1.27 to 1.08).</p><p><b>CONCLUSION</b>Adding the recombinant adenoviruses only suppresses the cell growth, but not promotes their apoptosis. In co-culture with T lymphocytes, recombinant adenovirus vector rAD-mTERT promotor-m4-1BBL can targetingly suppress the growth and induce apoptosis of Hepa1-6 cells. The apoptosis is induced through the immunological killing effect of T lymphocytes.</p>

CD137-CD137 Ligand Interactions in Inflammation

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.

Transgenic 4-1-BB ligand therapy induces tumor specific immune response in oral squamous cell carcinoma / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To examine the activation and cytotoxicity of human peripheral blood T lymphocyte induced in vitro by human 4-1-BB ligand (4-1-BBL) gene transfected into tumor Tca8113 cells.</p><p><b>METHODS</b>The eukaryotic expression vector pEGFP-h4-1-BBL was transfected into human oral carcinoma cell line Tca8113 by Lipofectamine 2000. The transfected cells were then selected in medium containing G-418, cloned by limited dilution and named as Tca8113-4-1-BBL. Human 4-1-BBL mRNA and protein expression of transfected cells was detected by reverse transcriptase-polymerase chain reaction (RT-PCR) and western blotting respectively. The tumor cell vaccines (TCV) were obtained by treatment with mitomycin (MMC). Human peripheral blood mononuclear cells (PBMC) were prepared from lymphoprep, and then stimulated with anti-CD-3 mAb and incubated with non-transfected or transfected TCV-Tca8113 cells, respectively. The proliferation of T cells was evaluated by trypan blue exclusion; the CCK-8 was used to detect the cytotoxic effect of T lymphocytes. Meanwhile, the secretion of interferon-gamma (IFN-gamma) and interleukin (IL)-2 in culture supernatant was detected by enzyme-linked immunosorbent assay (ELISA).</p><p><b>RESULTS</b>The Tca8113 cells transfected by pEGFP-h4-1-BBL could express human 4-1-BBL efficiently. As compared with wild type Tca8113 cells, the transfected Tca8113 cells could markedly promote proliferation, IL-2 and IFN-gamma production and cytotoxic activity of lymphocytes.</p><p><b>CONCLUSIONS</b>The transfection of human 4-1-BBL gene in Tca8113 cells is effective in enhancing its immunogenicity and inducing antitumor immune response in vitro.</p>

Expression of 4-1BB and 4-1BBL in thymocytes during thymus regeneration

4-1BB, a member of the tumor necrosis factor receptor (TNFR) superfamily, is a major costimulatory receptor that is rapidly expressed on the surface of CD4+ and CD8+ T cells after antigen- or mitogen-induced activation. The interaction of 4-1BB with 4-1BBL regulates immunity and promotes the survival and expansion of activated T cells. In this study, the expression of 4-1BB and 4-1BBL was examined during regeneration of the murine thymus following acute cyclophosphamide-induced involution. Four-color flow cytometry showed that 4-1BB and 4-1BBL were present in the normal thymus and were preferentially expressed in the regenerating thymus, mainly in CD4+CD8+ double-positive (DP) thymocytes. Furthermore, the CD4loCD8lo, CD4+CD8lo and CD4loCD8+ thymocyte subsets, representing stages of thymocyte differentiation intermediate between DP and single-positive (SP) thymocytes, also expressed 4-1BB and 4-1BBL during thymus regeneration but to a lesser degree. Interestingly, the 4-1BB and 4-1BBL positive cells among the CD4+CD8+ DP thymocytes present during thymus regeneration were TCR(hi) and CD69+ unlike the corresponding controls. Moreover, the 4-1BB and 4-1BBL positive cells among the intermediate subsets present during thymus regeneration also exhibited TCRhi/int and CD69+/int phenotypes, indicating that 4-1BB and 4-1BBL are predominantly expressed by the positively selected population of the CD4+CD8+ DP and the intermediate thymocytes during thymus regeneration. RT-PCR and Western blot analyses confirmed the presence and elevated levels of 4-1BB and 4-1BBL mRNA and protein in thymocytes during thymus regeneration. We also found that the interaction of 4-1BB with 4-1BBL promoted thymocyte adhesion to thymic epithelial cells. Our results suggest that 4-1BB and 4-1BBL participate in T lymphopoiesis associated with positive selection during recovery from acute thymic involution.

Study on the construction and expression of the human 4-1BBL extracellular domain/anti-CD20 Fab' fusion protein / 生物工程学报

Several studies have demonstrated the role of 4-1BBL in T cell activation. Furthermore, enhanced 4-1BB/4-1BBL interaction has been shown to amplify T-cell-mediated antitumor immunity in several mouse models. However, when applied in humans, it was difficult to generate sufficient T cells ex vivo and whole cell vaccines to transfer back into patients. To overcome this difficulty, we have focused on producing the human 4-1BBL extracellular domain/anti-CD20 Fab' fusion protein. In this report, PCR and overlap PCR were used to construct the human 4-1BBL extracellular domain/anti-CD20 Fab' expression vector. DNA sequence was analyzed by the Terminus of Dideoxy Nucleotide. The product was purified by affinity chromatography and analyzed by SDS-PAGE and HPLC; its antigen binding activity was examined by rosetting assay. The data of DNA sequence showed that the human 4-1BBL extracellular domain/anti-CD20 Fab' fusion protein was corrected. The fusion protein was recovered in high yield (up to 200 microg/mL) after E-taq purification. The fusion protein was capable of simultaneous binding to stimulated Jurkat cells and Raji cells as shown by cellular rosetting. In conclusion, the human 4-1BBL extracellular domain/anti-CD20 Fab' fusion protein was induced to express in E. coli 16C9. The results of some biological activity experiments indicated that the fusion protein could bind to stimulated Jurkat cells and Raji cells. Furthermore, 4-1BBL-negative tumors can be converted into 4-1BBL-positive tumors by the fusion protein without the need for 4-1BBL gene transfer to the malignant cells.

Preferential T cell expansion by artificial antigen presenting cells expressing 4-1BBL alone or in combination with CD80 or CD86

Varieties of artificial antigen presenting cells [aAPCs] with different efficiencies have been introduced to expand whole T cell population or antigen specific ones for the purpose of T cell therapy. From antibody coated beads to gene modified dendritic cells each has some advantages and disadvantages. However, no one can ignore the importance and the necessity of costimulation interaction during T cell activation. This study was designed to compare the effectiveness of CD80/CD86 and 4-1BBL, two major costimulatory families, in costimulation of autologous T cell responses. We used recombinant non-replicative adenoviral vectors and transferred genes of these ligands to autologous blood monocytes and skin fibroblasts to create aAPCs system. T cell response to anti-CD3 pan stimulation and some viral peptide Ags, in co-culture with gene modified monocytes and fibroblasts were studied using CFSE and HLA tetramers, respectively. Over-expression of ligands was able to expand the T cell population significantly higher than normal cells with no interference with antigen stimulation. Presence of 4-1BBL alone or in combination with B7 members enhanced T cell expansion and promoted more Ag-specific cells to accumulate in these culture systems. Considering the inhibitory proportion of B7 costimulation route, 4-1BBL, as an alternative signaling pathway, in combination with B7 will promote T cell proliferation and expansion

Mechanism of enhancement of the CTL activity in mice co-expressing CD80, CD86 and CD137L genes / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To study the mechanism of enhancement of the CTL activity in mice co-expressing of CD80, CD86 and CD137L genes.</p><p><b>METHODS</b>The mice were randomly divided into five groups, named A, B, C, D and E. The group A and B were control groups (CG). H22-BAL B/c HCC mouse model was established by subcutaneous injection with hepatocellular carcinoma cells of cell line H22-Wt (group A), H22-neo (group B), H22-CD80/CD86(+) (group C), H22-CD137L(+) (group D) and H22-CD80/CD86/CD137L(+) (group E), respectively. On the 14th, 35th, 56th and 84th day after the first inoculation of tumor cells, TUNEL staining and DNA ladder examination were used to detect apoptosis of splenic T lymphocytes in all groups at each post-inoculation time point. Electrophoretic mobility-shift assay (EMSA) method was used to detect the activity of nuclear factor kappaB (NF-kappaB) in splenic T lymphocytes in each group at each time point post-inoculation.</p><p><b>RESULTS</b>Apoptosis was found in a great number of T lymphocytes in CG on the 14th day, much more than that in group C and E. The number of apoptotic T cells in group C had a significant difference compared with that in the group E from 14th to 84th day (P = 0.003). DNA ladder analysis showed typical positive results in group C and E. The significant apoptosis fragments were found in group C on 21st, 35th and 84th days. NF-kappaB activity of T cells in groups C and E was remarkably higher than that of groups CG and D, with higher in group D than that of CG (P = 0.002), and with no significant difference between group C and E on 14th day. The activity in group E was stable and remarkably higher than that of group C on 56th and 84th days after the first inoculation.</p><p><b>CONCLUSION</b>H22-CD80/CD86/CD137L(+) induces higher NF-kappaB activity of the host T cells by synergistic action of CD28 and CD137, which may be one of the mechanisms of enhancement of the host CTL activity induced by co-expression of CD80, CD86 and CD137L genes.</p>

Study on control of graft-versus-host disease by blocking CD137-CD137L ligand costimulatory pathway in mice / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore the in vitro effect on control of graft-versus-host disease (GVHD) and its mechanism in mice by blockade of CD137-CD137L pathway.</p><p><b>METHODS</b>Responder spleen cells from BALB/c donor mice (H-2(d)) were incubated with stimulator spleen cells from C57BL/6 ( H-2(b)) recipient mice, with or without anti-CD137L mAb. Lethally irradiated C57BL/6 mice were transplanted with donor bone marrow cells plus primary MLC spleen T cells. Group A (Allo-BMT control group): allo-BMT mice not receiving any prevention measures for GVHD. Group B (CsA + MTX control group): CsA and MTX given to C57BL/6 mice after transplantation. Group C (experimental group): donor spleen cells from BALB/c mice treated with anti-CD137L mAb. The percentages of CD3+ CD8+ T and CD3+ CD4+ T cells in the three groups were detected by flow cytometry, and the level of cytokines (IFN-gamma, IL-2, IL-10, IL-4) by RT-PCR.</p><p><b>RESULTS</b>The incidence of GVHD in group C was 70%, while in group A and group B were 100%. The survival rate was higher and the median survival time was longer of group C than that of group A and B (P < 0.01). All mice in group A died of aGVHD within 15 ds, while 30% of mice in group C survived more than 30 ds. Symptoms and histological signs of GVHD in group C were the mildest among the three groups. The percentage of CD3+ CD8+ T cells and the levels of IFN-gamma were significantly lower (P < 0.01), and the levels of IL-10 were significantly higher in group C than those in group A and B (P < 0.01).</p><p><b>CONCLUSION</b>Treatment of donor T cells with anti-CD137L mAb in vitro may relieve GVHD, thereby improve the survival time and survival rate, which maybe related to increasing Th1 cytokine (IFN-gamma) and decreasing Th2 cytokine (IL-10) as well as reducing CD3+ CD8+ T cells.</p>