Enhanced efficacy of CD19/CD22 bispecific CAR-T cells with EAAAK linker on B-cell malignancies.

OBJECTIVES: Despite the great success of CD19 CAR-T cell therapy, its clinical efficacy has been greatly hampered by the high relapse rate. In this study, we designed and compared four structures of CD19/CD22 bispecific CAR-T cells with different linkers and different orders of the antibody sequences. METHODS: We detected the cytotoxicity, cytokine secretion levels, sustainable killing ability, differentiation, exhaustion of these four CAR-T cells in vitro. The optimal Bis-C CAR-T cells were evaluated the efficacy using NSG mice. RESULTS: The two structures of CD19/CD22 bispecific CAR-T cells using (EAAAK)3 as linker had more significant cytotoxicity and cytokine secretion levels. In the process of continuous killing, Bis-C CAR-T cells showed better sustained killing ability, memory phenotype differentiation, and exhaustion. In the in vivo experiment mimicking CD19-negative relapse, Bis-C CAR-T was more able to control the tumor progression of mice in the CD19 low expression or no expression groups than CD19 CAR-T. CONCLUSIONS: This study has generated a novel bispecific CAR-T cell that can simultaneously target CD19 or CD22 positive tumor cells, providing a new strategy to address the limitations of single-targeted CAR-T therapy in B-cell tumors (limited response or relapse).

Preconditioning of radiotherapy enhances efficacy of B7-H3-CAR-T in treating solid tumor models.

AIMS: Limited efficacy of chimeric antigen receptor T (CAR-T) cells in treating solid tumors is largely due to the antigen heterogeneity and immunosuppressive tumor microenvironment (TME). B7-H3 is over-expressed in most kind of solid tumors, making it a promising target for cancer treatment. This study aims to explore the effect of B7-H3-CAR-T therapy combined with radiotherapy in treating solid tumor models. METHODS: Irradiated tumor cell lines were prepared and tested. A humanized B7-H3-CAR-T was constructed, and it was evaluated that B7-H3-CAR-T cytotoxicity against solid tumor models with preconditioning of radiotherapy in vitro and vivo. RESULTS: Irradiation was found to increase expression level of B7-H3 in pancreatic cancer (PANC-1), colorectal cancer (HCT-15, SW620), acute myelocytic leukemia (AML-5), epidermoid carcinoma (KB) and glioma (U87-MG) human cell lines significantly. 6Gy irradiation was also found to up-regulate tumor-infiltration molecule like intracellular adhesion molecule-1 ICAM-1 or FAS in HCT-15 cells, supporting a possible synergistic enhancement effect of radiotherapy. In vitro and in vivo experiments demonstrated that irradiation indeed significantly enhanced the ability of B7-H3-CAR-T to infiltrate and kill tumors. Interestingly in dual-tumor mouse model study, not only tumor cells on irradiation side were eradicated completely, irradiation also enhanced CAR-T tumor-killing ability on non-irradiated side, confirming the abscopal effect of irradiation existed with CAR-T therapy. CONCLUSIONS: Our results suggest that B7-H3-CAR-T therapy combined with radiotherapy may be a promising modality in treating solid tumors.

CD7 protein plays a crucial role in T cell infiltration in tumors.

CD7 protein as a target is being used to treat CD7+ lymphoma; however, the role of CD7 in the hematopoietic system remains largely unknown. Therefore, we evaluated the effects of CD7 KO in mice. The differentiation of the hematopoietic system in the bone marrow and the number of various cell types in the thymus and spleen did not differ between CD7 KO and WT mice. After subcutaneous inoculation of B16-F10 melanoma cells, tumors from CD7 KO mice grew more rapidly, and the proportion of CD8+ T cells in the spleen and tumors decreased. In vitro, the infiltration and adhesion of CD8+ T cells from the spleen of CD7 KO mice were weakened. Blocking CD7 in normal T cells did not alter the migration and infiltration, but in Jurkat, CCRF-CEM, and KG-1a tumor cell lines, migration and invasion were significantly reduced after blocking CD7. Therefore, CD7 does not affect hematopoietic system development but plays a crucial role in T cell infiltration into tumors.

B7-H3 chimeric antigen receptor-modified T cell shows potential for targeted treatment of acute myeloid leukaemia.

BACKGROUND AND AIMS: Chimeric antigen receptor (CAR)-T cell therapy is a novel type of immunotherapy. However, the use of CAR-T cells to treat acute myeloid leukaemia (AML) has limitations. B7-H3 is expressed in several malignancies, including some types of AML cells. However, its expression in normal tissues is low. Therefore, B7-H3 is ideal for targeted AML therapy. MATERIALS AND METHODS: First, we constructed B7-H3 CAR that can target B7-H3, and then constructed B7-H3-CAR-T cells in vitro, which were co-incubated with six AML cell lines expressing different levels of B7-H3, respectively. The toxicity and cytokines were detected by flow cytometry. In vivo, AML model was established in B-NSG mice to study the toxicity of B7-H3-CAR T on AML cells. RESULTS: In vitro functional tests showed that B7-H3-CAR-T cells were cytotoxic to B7-H3-positive AML tumor cells and had good scavenging effect on B7-H3-expressing AML cell lines, and the cytokine results were consistent. In vivo, B7-H3-CAR-T cells significantly inhibited tumor cell growth in a mouse model of AML, prolonging mouse survival compared with controls. CONCLUSION: B7-H3-CAR-T cells may serve as a novel therapeutic method for the targeted treatment of AML.

Autologous Nanobody-Derived Fratricide-Resistant CD7-CAR T-cell Therapy for Patients with Relapsed and Refractory T-cell Acute Lymphoblastic Leukemia/Lymphoma.

PURPOSE: Since CD7 may represent a potent target for T-lymphoblastic leukemia/lymphoma (T-ALL/LBL) immunotherapy, this study aimed to investigate safety and efficacy of autologous CD7-chimeric antigen receptor (CAR) T cells in patients with relapsed and refractory (R/R) T-ALL/LBL, as well as its manufacturing feasibility. PATIENTS AND METHODS: Preclinical phase was conducted in NPG mice injected with Luc+ GFP+CCRF-CEM cells. Open-label phase I clinical trial (NCT04004637) enrolled patients with R/R CD7-positive T-ALL/LBL who received autologous CD7-CAR T-cell infusion. Primary endpoint was safety; secondary endpoints included efficacy and pharmacokinetic and pharmacodynamic parameters. RESULTS: CD7 blockade strategy was developed using tandem CD7 nanobody VHH6 coupled with an endoplasmic reticulum/Golgi-retention motif peptide to intracellularly fasten CD7 molecules. In preclinical phase CD7 blockade CAR T cells prevented fratricide and exerted potent cytolytic activity, significantly relieving leukemia progression and prolonged the median survival of mice. In clinical phase, the complete remission (CR) rate was 87.5% (7/8) 3 months after CAR T-cell infusion; 1 patient with leukemia achieved minimal residual disease-negative CR and 1 patient with lymphoma achieved CR for more than 12 months. Majority of patients (87.5%) only had grade 1 or 2 cytokine release syndrome with no T-cell hypoplasia or any neurologic toxicities observed. The median maximum concentration of CAR T cells was 857.2 cells/µL at approximately 12 days and remained detectable up to 270 days. CONCLUSIONS: Autologous nanobody-derived fratricide-resistant CD7-CAR T cells demonstrated a promising and durable antitumor response in R/R T-ALL/LBL with tolerable toxicity, warranting further studies in highly aggressive CD7-positive malignancies.

Nanobody-based anti-CD22-chimeric antigen receptor T cell immunotherapy exhibits improved remission against B-cell acute lymphoblastic leukemia.

Chimeric antigen receptor (CAR) T-cell immunotherapies targeting CD19 can achieve impressive clinical remission rates in the treatment of B-cell non-Hodgkin lymphoma and B-cell acute lymphoblastic leukemia. However, relapse after CD19-CAR T treatment remains a major issue, with CD19 antigen-negative relapse being one of the main reasons. CD22, another antigen expressed in a B-cell lineage-specific pattern, is retained following CD19 loss. Accordingly, we hypothesized that CD22 could represent an alternative target to alleviate or compensate for the ineffectiveness of CD19-CAR T therapy. To this end, we generated camelid-derived CD22 nanobodies, whose smaller size, greater stability, and lower immunogenicity offer better quality than classical antibodies, and we used them to construct third-generation CD22-CARs containing 4-1BB and ICOS co-stimulatory domains. The novel CD22-CAR T cells exhibited impressive cytotoxicity both in vitro and in vivo and significantly prolonged the overall survival of tumor-bearing NSG mice. These findings provide the basis for further translational studies employing CD22-CARs.

Chimeric antigen receptor T cells derived from CD7 nanobody exhibit robust antitumor potential against CD7-positive malignancies.

The great success of chimeric antigen receptor T (CAR-T)-cell therapy in B-cell malignancies has significantly promoted its rapid expansion to other targets and indications, including T-cell malignancies and acute myeloid leukemia. However, owing to the life-threatening T-cell hypoplasia caused by CD7-CAR-T cells specific cytotoxic against normal T cells, as well as CAR-T cell-fratricide caused by the shared CD7 antigen on the T-cell surface, the clinical application of CD7 as a potential target for CD7+ malignancies is lagging. Here, we generated CD7ΔT cells using an anti-CD7 nanobody fragment coupled with an endoplasmic reticulum/Golgi retention domain and demonstrated that these cells transduced with CD7-CAR could prevent fratricide and achieve expansion. Additionally, CD7ΔCD7-CAR-T cells exhibited robust antitumor potiential against CD7+ tumors in vitro as well as in cell-line and patient-derived xenograft models of CD7-positive malignancies. Furthermore, we confirmed that the antitumor activity of CD7-CAR-T cells was positively correlated with the antigen density of tumor cells. This strategy adapts well with current clinical-grade CAR-T-cell manufacturing processes and can be rapidly applied for the therapy of patients with CD7+ malignancies.

MUC1-Tn-targeting chimeric antigen receptor-modified Vγ9Vδ2 T cells with enhanced antigen-specific anti-tumor activity.

Chimeric antigen receptor (CAR) αß T cell adoptive immunotherapy has shown great promise for improving cancer treatment. However, there are several hurdles to overcome for the wide clinical application of CAR-αß T cells therapy, including side effects and a limited T cells source from cancer patients. Therefore, we sought to identify an alternative T cell subset that could avoid these limitations and improve the effectiveness of CAR-T immunotherapy. γδ T cells are a minor subset of T cells, which share the characteristic of innate immune cells and adaptive immune cells. Vγ9Vδ2 T cells are a predominant γδ T subset in the circulating peripheral blood. In this study, we investigated the antigen-specific antitumor activity of CAR-Vγ9Vδ2 T cells targeting MUC1-Tn antigen. Vγ9Vδ2 T cells were expanded from peripheral blood mononuclear cells of healthy volunteers with zoledronic acid and interleukin-2. CAR-Vγ9Vδ2 T cells were generated by transfection of lentivirus encoding MUC1-Tn CAR. Cytotoxicity assays with various cancer cell lines revealed that CAR-Vγ9Vδ2 T cells could effectively lyse tumor cells in an antigen-specific manner, with similar or stronger effects than CAR-αß T cells. However, CAR-Vγ9Vδ2 T cells had shorter persistence, which could be improved with the addition of IL-2 to maintain the function of CAR-Vγ9Vδ2 T cells with consecutive stimulation of tumor cells. Using a xenograft mouse model, we further showed that CAR-Vγ9Vδ2 T cells more effectively suppressed tumor growth in vivo than Vγ9Vδ2 T cells. Therefore, MUC1-Tn CAR-modified Vγ9Vδ2 T cells may represent a novel, promising ready-to-use product for cancer allogeneic immunotherapy.

[Killing Effect of A CD7 Chimeric Antigen Receptor-Modified NK-92MI Cell Line on CD7-Positive Hematological Malignant Cells].

OBJECTIVE: To investigate the killing effect of NK-92MI cells modified by chimeric antigen receptor (CD7-CAR) and specifically targeting CD7 to CD7+ hematological malignant cells. METHODS: Three types of hematological malignant tumor cells, including 5 cases of CD7+ acute T-lymphoblastic leukemia (T-ALL), 10 cases of acute myeloid leukemia (AML) and 6 cases of T-cell lymphoma were collected, centrifuged, cultured and used to detect the expression levels of tumor cell surface targets; 7-AAD, CD56-APC, CD3-FITC, IgG Fc-PE flow cytometry were used to detected the transfection efficiency of NK-92MI and CD7-CAR-NK-92MI cells, killing efficiencies of CD7-CAR-NK-92MI cells to CD7+ hematological tumor cells in vitro were determined by flow cytometry using PE Annexin V Apoptosis Detection Kit. Secretion differences of NK-92MI and CD7-CAR-NK-92MI cytokines interleukin (IL)-2, interferon (IFN)-γ, and granzyme B detection were estimated by using CBA kit. RESULTS: The killing efficiencies of CD7-CAR-modified NK-92MI cells to CD7+ T-ALL, AML, T-cell lymphoma tumor cells were significantly higher than those of NK-92MI cells without genetical modification. The difference showed statistically significant (P＜0.05). The level of IFN-γ and granzyme B were significantly increased among cytokines secreted by CD7-CAR-modified NK-92MI cells as compared with those of NK-92MI cells without genetical modification (P＜0.05) . CONCLUSION: CD7-CAR-modified NK-92MI cells have significantly improved killing efficiency against CD7+ T-ALL, AML and T lymphoma cells, and shows specific targeting effects, which provides a clinical basis for the treatment of CD7+ hematological malignancies.

Research progression on the first-line biological target therapy of advanced / 中国肿瘤生物治疗杂志

@#[Abstract] Objective: To develop a new type of CD7 chimeric antigen receptor modified T cell (CD7-CAR-T) for the treatment of CD7 positive acute myeloid leukemia (AML), and to observe its killing effect on CD7 positive AML cells. Methods: The CD7-CAR lentiviral vector was constructed based on the CD7 Nanobody sequence and costimulatory domain sequence of CD28 and 4-1BB. The lentiviral particles were packaged and used to co-transfect human T cells with protein expression blocker (PEBL), so as to prepare CD7- CAR-T cells. Real time cellular analysis (RTCA) was used to monitor the cytotoxicity of CD7-CAR-T cells on CD7 overexpressed 293T cells. Flow cytometry assay was used to detect the effect of CD7-CAR-T cells on proliferation and cytokine secretion of AML cells with high, medium and low CD7 expressions (KG-1, HEL and Kasumi-1 cells, respectively). Results: CD7-CAR-T cell was successfully constructed and its surface expression of CD7 was successfully blocked. Compared with T cells, CD7-CAR-T cells could significantly inhibit the proliferation of CD7-293T cells and promote the release of TNF, Granzyme B and INF-γ; in addition, CD7-CAR-T cells also significantly promoted the apoptosis (t=147.1, P<0.01; t=23.57, P<0.01) and cytokine release (P<0.05 or P<0.01) in CD7 positive KG-1 and HEL cells, but had little effect on Kasumi-1 cells that only expressed minimal CD7 antigen (t=0.7058, P>0.05). Conclusion: CD7-CAR-T cells can specifically kill CD7-positive AML cells in vitro.

Decitabine enhances cytotoxic effect of T cells with an anti-CD19 chimeric antigen receptor in treatment of lymphoma.

Background: CD19-directed chimeric antigen receptor (CAR) T cells have substantial benefit in the treatment of patients with B-cell malignancies. However, despite encouraging therapeutic efficiency, there is limited overall response rate when anti-CD19 CAR-T cells are used to treat patients with relapsed and refractory (R/R) B cell lymphomas. Therefore, it further investigation is urgently needed to improve treatment efficacy. Method: A combined treatment protocol of CAR-T cell with decitabine (DAC) to treat B cell lymphoma was developed and tested on lymphoma cell lines first, and then efficacy and the underlying mechanism were investigated. After ethical approval was granted, the combined treatment protocol was applied to treat two patients with R/R B-cell lymphomas. Results: CAR-T cells were prepared successfully, and they recognized CD19 antigen expressed on lymphoma cell lines specifically. Cell-line studies also showed that CD19 antigen expression was increased by DAC pretreatment, and the function of CAR-T cells was not compromised. The cell-line study further demonstrated that lymphoma cells pretreated by DAC responded more to the treatment of CAR-T cells. Two patients with R/R B cell lymphoma were pretreated with DAC then treated with CAR-T, and both achieved complete remission (CR). Conclusions: The epigenetic modifying drug DAC increases expression of the surface antigen CD19 on lymphoma cells. The DAC pretreatment protocol may lead patients with B cell lymphoma to be more susceptible to adoptive transfer of anti-CD19 CAR-T cells treKeywordsatment.

A novel CD7 chimeric antigen receptor-modified NK-92MI cell line targeting T-cell acute lymphoblastic leukemia.

Chimeric antigen receptor (CAR) immunotherapy has recently shown promise in clinical trials for B-cell malignancies; however, designing CARs for T-cell based diseases remain a challenge since most target antigens are shared between normal and malignant cells, leading to CAR-T cell fratricide. CD7 is highly expressed in T-cell acute lymphoblastic leukemia (T-ALL), but it is not expressed in one small group of normal T lymphocytes. Here, we constructed monovalent CD7-CAR-NK-92MI and bivalent dCD7-CAR-NK-92MI cells using the CD7 nanobody VHH6 sequences from our laboratory. Both CD7-CAR-NK-92MI and dCD7-CAR-NK-92MI cells consistently showed specific and potent anti-tumor activity against T-cell leukemia cell lines and primary tumor cells. We observed robust cytotoxicity of the bivalent mdCD7-CAR-NK-92MI monoclonal cells against primary T-ALL samples. In agreement with the enhanced cytotoxicity of mdCD7-CAR-NK-92MI cells, significant elevations in the secretion of Granzyme B and interferon γ (IFN-γ) were also found in mdCD7-CAR-NK-92MI cells in response to CD7-positive primary T-ALL cells compared with NK-92MI-mock cells. Furthermore, we also demonstrated that mdCD7-CAR-NK-92MI cells significantly inhibited disease progression in xenograft mouse models of T-ALL primary tumor cells. Our data suggest that CD7-CAR-NK-92MI cells can be used as a new method or a complementary therapy for treating T-cell acute lymphocytic leukemia.

Erratum: First-in-man clinical trial of CAR NK-92 cells: safety test of CD33-CAR NK-92 cells in patients with relapsed and refractory acute myeloid leukemia.

[This corrects the article on p. 1083 in vol. 8, PMID: 30034945.].

First-in-man clinical trial of CAR NK-92 cells: safety test of CD33-CAR NK-92 cells in patients with relapsed and refractory acute myeloid leukemia.

CAR T cells have shown clinical efficacy for acute lymphoblastic leukemia, but this therapy has not been effective for acute myeloid leukemia (AML), and other treatment options are needed. Theoretically, CAR-NK cells have a more favorable toxicity profile compared to CAR T cells, especially in avoiding adverse effects such as cytokine release syndrome. However, the clinical evidence for this has not yet been reported. In the current study, we tested the safety of CD33-CAR NK cells in patients with relapsed and refractory AML. At doses up to 5 × 109 (5 billion) cells per patient, no significant adverse effects were observed. CAR NK-92 cells can be produced at much lower cost compared to CAR T cells, and we believe after being optimized, they will be widely accessible for the treatment of cancer.

Gene-modified NK-92MI cells expressing a chimeric CD16-BB-ζ or CD64-BB-ζ receptor exhibit enhanced cancer-killing ability in combination with therapeutic antibody.

Natural killer (NK) cells play a pivotal role in monoclonal antibody-mediated immunotherapy through the antibody-dependent cell-mediated cytotoxicity (ADCC) mechanism. NK-92MI is an interleukin-2 (IL-2)-independent cell line, which was derived from NK-92 cells with superior cytotoxicity toward a wide range of tumor cells in vitro and in vivo. Nonetheless, the Fc-receptor (CD16) that usually mediates ADCC is absent in NK-92 and NK-92MI cells. To apply NK-92MI cell-based immunotherapy to cancer treatment, we designed and generated two chimeric receptors in NK-92MI cells that can bind the Fc portion of human immunoglobulins. The construct includes the low-affinity Fc receptor CD16 (158F) or the high-affinity Fc receptor CD64, with the addition of the CD8a extracellular domain, CD28 transmembrane domains, two costimulatory domains (CD28 and 4-1BB), and the signaling domain from CD3ζ. The resulting chimeric receptors, termed CD16-BB-ζ and CD64-BB-ζ, were used to generate modified NK-92MI cells expressing the chimeric receptor, which were named NK-92MIhCD16 and NK-92MIhCD64 cells, respectively. We found that NK-92MIhCD16 and NK-92MIhCD64 cells significantly improved cytotoxicity against CD20-positive non-Hodgkin's lymphoma cells in the presence of rituximab. These results suggest that the chimeric receptor-expressing NK-92MI cells may enhance the clinical responses to currently available anticancer monoclonal antibodies.

Phase 1 clinical trial demonstrated that MUC1 positive metastatic seminal vesicle cancer can be effectively eradicated by modified Anti-MUC1 chimeric antigen receptor transduced T cells.

Recent progress in chimeric antigen receptor-modified T-cell (CAR-T cell) technology in cancer therapy is extremely promising, especially in the treatment of patients with B-cell acute lymphoblastic leukemia. In contrast, due to the hostile immunosuppressive microenvironment of a solid tumor, CAR T-cell accessibility and survival continue to pose a considerable challenge, which leads to their limited therapeutic efficacy. In this study, we constructed two anti-MUC1 CAR-T cell lines. One set of CAR-T cells contained SM3 single chain variable fragment (scFv) sequence specifically targeting the MUC1 antigen and co-expressing interleukin (IL) 12 (named SM3-CAR). The other CAR-T cell line carried the SM3 scFv sequence modified to improve its binding to MUC1 antigen (named pSM3-CAR) but did not co-express IL-12. When those two types of CAR-T cells were injected intratumorally into two independent metastatic lesions of the same MUC1(+) seminal vesicle cancer patient as part of an interventional treatment strategy, the initial results indicated no side-effects of the MUC1 targeting CAR-T cell approach, and patient serum cytokines responses were positive. Further evaluation showed that pSM3-CAR effectively caused tumor necrosis, providing new options for improved CAR-T therapy in solid tumors.

First BAFF gene cloned from an aquatic mammal.

The finless porpoise (Neophocaena phocaenoides) is one of the smallest cetacean species. Research into the immune system of the finless porpoise is essential to the protection of this species, but, to date, no genes coding for proteins from the tumor necrosis factor family (TNF family) have yet been reported from finless porpoises. The TNF B cell activating factor (BAFF) is critical to B cell survival, proliferation, maturation, and immunoglobulin secretion and to T cell activation. It acts through its three receptors, BAFF-R, BCMA, and TACI. In the present study, the full-length cDNA of BAFF (designated NpBAFF) from the finless porpoise was cloned using RT-PCR and rapid amplification of cDNA ends (RACE) techniques, and its biological activities have been characterized. To our knowledge, this is the first report of any BAFF gene being cloned from an aquatic mammal. The full-length cDNA of NpBAFF consists of 1502 bases including an 852 bp open reading frame encoding 283 amino acids. This protein was found to contain a predicted transmembrane domain, a putative furin protease cleavage site, and a typical TNF homology domain corresponding to other, known BAFF homologues. Sequence comparison indicated that the amino acid sequence of NpBAFF was very similar to its bovine (87.68%), porcine (76.33%), hircine (87.68%) and canine (82.19%) counterparts. The predicted three-dimensional (3D) structure of the NpsBAFF monomer, analyzed by comparative protein modeling, revealed that it was very similar to its human counterpart. Phylogenetic analysis indicated that NpBAFF showed a notable homology with Artiodactyla BAFFs. The SUMO-NpsBAFF was efficiently expressed in Escherichia coli BL21 (DE3) and confirmed by SDS-PAGE and Western blot analysis. Laser scanning confocal microscopy analysis showed that NpsBAFF could bind to its receptors on B cells. In vitro, MTT assays indicated that SUMO-NpsBAFF could promote the survival or proliferation of mouse splenic B cells grown with anti-mouse IgM. These findings indicate that NpBAFF plays an important role in the survival or proliferation of B cells and has functional cross-reactivity among cetaceans and other mammals. The present findings may provide valuable information for research into the immune system of the finless porpoise.

Molecular structure, expression analysis and functional characterization of APRIL (TNFSF13) gene in bat (Vespertilio superans Thomas).

A proliferation-inducing ligand (APRIL) is a novel member of the tumor necrosis factor (TNF) superfamily, which is involved in immune regulation. In the present study, the full-length cDNA of APRIL (designated bAPRIL) from bat was cloned using RT-PCR and its biological activities have been characterized. The open reading frame (ORF) of this cDNA consists of 753 bases, encoding a protein of 250 amino acids. This protein was found to contain a predicted transmembrane domain, a putative furin protease cleavage site, and a typical TNF homology domain corresponding to other, known APRIL homologs. Real-time quantitative PCR (qPCR) analysis indicated that bAPRIL mRNA was predominantly expressed in bat lymphoid tissue spleen. The SUMO-bsAPRIL was efficiently expressed in Escherichia coli BL21 (DE3) and confirmed by SDS-PAGE and Western blot analysis. Laser scanning confocal microscopy analysis showed that bsAPRIL could bind to its receptors on B cells. In vitro, MTT assays indicated that bsAPRIL could promote the survival/proliferation of mouse splenic B cells grown with anti-mouse IgM. These findings indicate that bsAPRIL plays an important role in the survival and proliferation of B cells and has functional cross-reactivity among mammalians. The present findings may provide valuable information for research into the immune system of the bat.

Molecular cloning, expression, bioinformatics analysis and bioactivity characterization of TNF13B (BAFF) gene in bat (Vespertilio superans Thomas).

B cell activating factor (BAFF) belonging to the tumor necrosis factor (TNF) family is critical to B cell survival, proliferation, maturation, and immunoglobulin secretion and to T cell activation. In the present study, the full-length cDNA of BAFF (designated bBAFF) from the bat (Vespertilio superans Thomas) was cloned using RT-PCR and rapid amplification of cDNA ends (RACE) techniques. The full-length cDNA of bBAFF consists of 986 bases including an 873 bp open reading frame encoding 290 amino acids. Sequence comparison indicated that the amino acid of bBAFF possessed the TNF signature, a transmembrane domain, a putative furin protease cleavage site and three cysteine residues. The predicted three-dimensional (3D) structure of the bsBAFF monomer, analyzed by comparative protein modeling, revealed that it was very similar to its counterparts. Real-time quantitative PCR (qPCR) analysis indicated that bBAFF mRNA was predominantly expressed in bat lymphoid tissue spleen. The SUMO (Small Ubiquitin-like Modifier)-bsBAFF was efficiently expressed in Escherichia coliBL21 (DE3) and confirmed by SDS-PAGE and Western blotting analysis. Laser scanning confocal microscopy analysis showed that bsBAFF could bind to its receptors on B cells. In vitro, the MTT assays indicated that SUMO-bsBAFF was not only able to promote survival/proliferation of bat lymphocytes but also able to stimulate survival/proliferation of mouse B cells. These findings indicate that bsBAFF plays an important role in the survival/proliferation of B cells and has functional cross-reactivity among mammalians. The present findings may provide valuable information for research into the immune system of the bat.

Molecular cloning, bioinformatics analysis and functional characterization of B-cell activating factor in goat (Capra hircus).

B-cell activating factor of the TNF family (BAFF) induces B cell survival, proliferation, immunoglobulin secretion and has a role in enhancing immune responses. In the present study, we amplified the cDNA of goat (Capra hircus) BAFF (designated gBAFF) from spleen by reverse transcription-PCR (RT-PCR). The open reading frame (ORF) of gBAFF covers 843 bp encoding 280 amino acids, with a 152-aa mature peptide. Sequence comparison indicated that the amino acid of gBAFF possessed the TNF signature, a transmembrane domain, a putative furin protease cleavage site and three cysteine residues. The predicted three-dimensional (3D) structure of the soluble part of gBAFF (gsBAFF) analyzed by "comparative protein modelling" revealed that it was very similar to its counterparts. Real-time quantitative PCR (qPCR) analysis indicated that gBAFF mRNA was predominantly expressed in goat lymphoid tissue spleen. Recombinant gsBAFF was fused with a small ubiquitin-related modifier (SUMO) gene to enhance the soluble expression level in Escherichia coli BL21 (DE3). The resulting fused protein SUMO-gsBAFF was efficiently expressed and purified using metal chelate affinity chromatography (Ni-NTA), then confirmed by SDS-PAGE and Western blotting analysis. In vitro, the MTT assays and flow cytometric analysis indicated that SUMO-gsBAFF as well as gsBAFF could promote the survival/proliferation of goat splenic B cells or mouse splenic B cells. Therefore, BAFF may be a potential immunologic factor for enhancing immunological efficacy in goat.