Therapeutic efficacy of Bifidobacterium longum-mediated human granulocyte colony-stimulating factor and/or endostatin combined with cyclophosphamide in mouse-transplanted tumors

Granulocyte colony-stimulating factor (GCSF) is frequently used as an adjunctive agent in tumor chemotherapy. Bifidobacterium longums (B. longum) attracted researchers' interests due to its enhancement of immunity and selective location in solid tumors. B. longum-pBV22210-endostatin (Endo) was proved to have a definite inhibitive effect on tumor growth in our previous study. In the present study, we evaluated the effects of B. longum-pBV22210-GCSF and/or B. longum-pBV22210-Endo combined with cyclophosphamide (CTX) on H22 and S180 tumor-bearing mice. Based on our previous work, the plasmid pBV22210-GCSF was constructed and transformed by electroporation into B. longum. The B. longum-pBV22210-GCSF and/or B. longum-pBV22210-Endo combined with CTX were applied to treat H22 and S180 tumor-bearing mice. A leukocyte count was carried out and the tumor inhibition rate was calculated after treatment. In our study, CTX combined with B. longum-pBV22210-GCSF significantly raised the leukocyte level of tumor-bearing mice, while combined with B. longum-pBV22210-GCSF alone or B. longum-pBV22210-Endo alone combinations with CTX inhibited tumor growth by over 65%. The results showed that B. longum-pBV22210-GCSF had an effective antagonistic effect on bone marrow inhibited by CTX and could inhibit tumor growth when it was combined with B. longum-pBV22210-Endo and CTX. Our results provide an enhanced understanding of B. longum and GCSF as well as their potential as an adjunctive approach in cancer gene therapy.

hMan2c1 transgene promotes tumor progress in mice

In order to study the biological significance of alpha-mannosidase Man2c1, hMan2c1 transgenic mice were developed. In 113 F0 mice, eight were found to be genomic PCR positive for hMan2c1; 9/20 (45%) F1 mice, 16/21 (76.2%) F2 mice, and 12/14 (85.7%) F3 mice were genomic PCR positive for hMan2c1. RT-PCR demonstrated hMan2c1 mRNA transcription in four of eight transgenic lines. Enzymatic activity on p-nitrophenyl-alpha-D: -mannopyranoside was enhanced in 35# and 54# transgenic mice and real-time RT-PCR showed hMan2c1 mRNA expression in these mice. Reduced Con A binding to splenocytes implied N-glycosylation modification of host proteins by hMan2c1 transgene. hMan2c1 transgene promoted growth, invasion, and metastasis to lung of implanted hepatoma H22 and sarcoma S180. The average weights of H22 and S180 tumors were 3.98 +/- 1.62, 3.29 +/- 0.76, 1.69 +/- 1.09, and 3.19 +/- 0.44, 2.72 +/- 1.38, 0.97 +/- 0.41 g for 35#, 54# transgenic mice and wild type mice (W), respectively, (35# or 54# versus W, paired t-test, P < 0.05). In 35# and 54# mice 5/10 and 3/10 showed lung metastasis of H22 tumor in contrast with 1/10 in W mice. In 35# and 54# mice 1/6 and 2/6 showed lung metastasis of S180 tumor in contrast with 0/6 in W mice. The possible mechanism of the promotion was explored on both humoral and cellular immunity. Reduced antibody response to BSA was observed in transgenic mice, suggesting that specific antibody response to tumor antigens might be suppressed by hMan2c1 transgene. However, NK cytotoxicity in splenocytes was not affected by the transgene.

Tumor suppressor function of BCSC-1 in nasopharyngeal carcinoma

BCSC-1 is dramatically upregulated in CNE-2L2 human nasopharyngeal carcinoma cells with reduced malignancy (AS cells) and is proposed to be a candidate tumor suppressor gene. We therefore examined the effect of BCSC-1 expression on malignant behaviors of CNE-2L2 cells. Growth in vitro and tumorigenesis in nude mice of wild-type CNE-2L2 cells (W cells) were inhibited by ectopic BCSC-1, and those of AS cells were promoted by BCSC-1 suppression. The tumor suppressor function of BCSC-1 was further confirmed by a study showing that intratumor BCSC-1 injection caused growth suppression of the tumor from W cells inoculated in nude mice. Immunohistochemistry exhibited marked reduction of BCSC-1 expression in 11 of 39 human nasopharyngeal carcinoma specimens. Because BCSC-1 expression was as rich as that in normal cells in the rest of the carcinoma specimens and was poor in CNE-2L2 cells, HNE-1 human nasopharyngeal carcinoma cells with rich BCSC-1 expression were used as a control in the study. No effect of BCSC-1 transfection on growth of the cells was observed. The data suggest that BCSC-1 suppression might play roles in tumorigenesis of some nasopharyngeal carcinomas and that BCSC-1 might be a potential gene therapy target in nasopharyngeal carcinomas with poor BCSC-1 expression. Enhanced aggregation of cells together with increased E-cadherin and alpha-catenin expression and reduced Wnt signaling might be involved in the mechanisms of tumor suppressor function of BCSC-1.

Two new sesquiterpene lactones from Sarcandra glabra

Two new sesquiterpene lactones (1) and (2), along with three known sesquiterpenes, atractylenolide beta (3), chloranthalactone E (4), and ( - )-istanbulin A (5), were isolated from the whole plant of Sarcandra glabra. The structures of two new compounds were established as 8beta,9alpha-dihydroxyeudesman-4(15),7(11)-dien-8alpha,12-olide (1) and 8beta,9alpha-dihydroxylindan-4(5),7 (11)-dien-8alpha,12-olide (2) on the basis of spectroscopic analysis. Compound 3 was isolated from this genus for the first time.

[Experimental BCSC-1 gene therapy on nasopharyngeal carcinoma mediated by adenovirus]

OBJECTIVE

To explore the therapeutic value of BCSC-1 in tumor gene therapy.

METHODS

Recombinant adenovirus Ad5-BCSC-1 was prepared. Cell proliferation was assayed using CellTiter 96 Aqueous one solution cell proliferation assay kit. Ad5-BCSC-1 was injected into tumor with Ad5-egfp or with PBS injection as controls. The injections were repeated one weak later. After another 2 weeks, the mice were sacrificed and the tumors were excised and weighed.

RESULTS

The growth of the CNE-2L2 cell infected with Ad5-BCSC-1 in vitro was remarkably slower than that of the controls, the wild type cell and the cell infected with Ad5-egfp. In contrast to the controls, the cells infected with Ad5-BCSC-1 aggregated and formed huge messes in the culture. The average weight of the CNE-2L2 tumors in mice was (2.28 +/- 0.73), (2.07 +/- 0.40), and (0.58 +/- 0.32) g for the tumors injected with PBS, Ad5-egfp, and Ad5-BCSC-1, respectively (Ad5-BCSC-1 vs. PBS or Ad5-egfp, P<0.05).

CONCLUSION

Intra-tumor injection of Ad5-BCSC-1 can suppress the growth of CNE-2L2 tumor in nude mice, suggesting that BCSC-1 gene therapy may be effective for tumors with low or no expression of BCSC-1 gene.

Clinical significance of increased CD4+CD25-Foxp3+ T cells in patients with new-onset systemic lupus erythematosus

OBJECTIVE

To investigate the expressions of Foxp3 and CD25 on CD4(+) T cells from patients with new-onset systemic lupus erythematosus (SLE) and assess their clinical significance.

METHODS

10 patients with active (systemic lupus erythematosus Disease Activity Index (SLEDAI) >or=10) and 11 with inactive (SLEDAI <or=5) new-onset SLE as well as 11 healthy volunteers were enrolled. The expressions of CD25, Foxp3 and CD127 on CD4(+) T cells were analysed by flow cytometry. Proliferation assays were performed on isolated CD4(+)CD25(+) or CD4(+)CD25(-) T cells, or both.

RESULTS

There was no significant difference in the number of CD4(+)CD25(+)Foxp3(+ )T cells in subjects with either active or inactive SLE compared with normal controls (p>0.05). Moreover, the suppressive capacity of CD4(+)CD25(+)T cells in patients with new-onset lupus was not impaired as measured by the ability to inhibit proliferation of CD4(+)CD25(-) T cells. Interestingly, CD4(+)CD25(-)Foxp3(+ )T cells in new-onset lupus (2.97-10.94%) were significantly more frequent than in normal controls (1.01-3.62%) (p<0.01), and correlated positively with the titres of anti-dsDNA antibodies (p = 0.029). Few of these cells expressed CD127. Treatment with glucocorticoids and cyclophosphamide reduced CD4(+)CD25(-)Foxp3(+) T cells in 8 of 10 patients with active disease.

CONCLUSIONS

There was a significant increase in CD4(+)CD25(-)Foxp3(+)T cells in patients with new-onset SLE that correlated with anti-dsDNA titres, whereas no alteration in either the percentage or function of CD4(+)CD25(+)Foxp3(+)T cells was observed.

[Predation of micro-protozoa on bacteria in Taihu Lake]

With dilution method, this paper studied the predation of different size micro-protozoa on bacteria in Taihu Lake, and approached the effects of the predation on bacterial growth and of the water temperature on the predation. The results showed that in the water body of Taihu Lake, the predation rate of micro-protozoa with its size less than 32 microm was 5.07 d(-1), and the nano-size (less than 16 microm) protozoa contributed about 90.7%. The predation of nano-protozoa reduced the abundance of bacteria significantly. With the increase of water temperature, the predation rate of nano-protozoa and the growth rate of bacteria increased obviously.

Inhibition of malignant activities of nasopharyngeal carcinoma cells with high expression of CD44 by siRNA

Since CD44 was found to be significantly inhibited in the human nasopharyngeal carcinoma cell line CNE-2L2 with profound reduction of malignant activities caused by inhibition of alpha-mannosidase Man2c1 gene expression and CD44 has been observed to be involved in many tumor-supporting functions, we studied the association of CD44 expression with the malignant activities of CNE-2L2 cells. Suppression of CD44 gene expression by RNA silencing technique resulted in profound reduction of malignant potential of the cells, including growth in vitro, colony formation, tumorigenesis and metastasis of tumors in nude mice. Direct injection of the adenoviruses harboring and producing siRNA to CD44 into the tumor inoculated with CNE-2L2 cells in nude mice caused inhibition of tumor growth. The data indicate a positive association of CD44 expression with the malignant activities of CNE-2L2 cells and suggest a possible therapeutic effect of direct introduction of siRNA to CD44 into tumors in some human solid tumors with high expression of CD44 gene.

Structure-based 3D-QSAR studies on heteroarylpiperazine derivatives as 5-HT3 receptor antagonists

Structure-based 3D-QSAR studies were performed on a series of novel heteroarylpiperazine derivatives as 5-HT(3) receptor antagonists with comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) methods. The compounds were initially docked into the binding pocket of the homology model of 5-HT(3) receptor using GOLD program. The docked conformations with the highest score were then extracted and used to build the 3D-QSAR models, with cross-validated r(cv)(2) values 0.716 and 0.762 for CoMFA and CoMSIA, respectively. The CoMFA and CoMSIA contour plots were also fitted into the 3D structural model of the receptor to identify the key interactions between them, which might be helpful for designing new potent 5-HT(3) receptor antagonists.

A quantitative method for measuring the antitumor potency of recombinant human endostatin in vivo

Recombinant human endostatin (rhEndostatin) has been shown to inhibit tumor growth, but the variable antitumor activity of different rhEndostatin preparations has necessitated the development of an accurate, reproducible in vivo bioassay for evaluating the rhEndostatin activity. To assess the in vivo antitumor efficacy of rhEndostatin, H22 tumor-bearing mice received three doses of rhEndostatin and the potency of rhEndostatin preparations in inhibiting tumor growth was determined by ED(50)-potency assay and validated by dose-response parallel-line assay. There was a consistent and highly reproducible linear regression relationship between rhEndostatin dosage and tumor growth inhibition rate. The ED(50) values were determined from dose-response regression lines for seven rhEndostatin preparations with high reproducibility. On the basis of the current study, the potency of rhEndostatin preparations was assigned a value of 6.09 x 10(5) U/ampoule and a 95% confidence limit of 5.96 x 10(5)-6.22 x 10(5). We consider that this procedure can be served as a potential candidate pharmacopoeial method for potency measurement of different rhEndostatin preparations.

Improved protein-adsorption resistance of polyethersulfone membranes via surface segregation of ultrahigh molecular weight poly(styrene-alt-maleic anhydride)

A styrene-maleic anhydride (SMA) alternating copolymer with ultrahigh molecular weight (M(w)>10(6)) synthesized in super critical carbon dioxide (SC CO(2)) medium was used as hydrophilic polymeric additive in the preparation of polyethersulfone (PES) membranes. The PES/SMA blend membranes were prepared by immersion precipitation process. X-ray photoelectronic spectroscopy (XPS) measurements confirmed that the hydrolyzed SMA preferentially segregated to membrane-coagulant interface during membrane formation. For the PES/SMA blend membranes, no big change was observed in the cross-sectional structure and the mechanical properties were well maintained after SMA addition except that a thicker top layer was formed. The surface morphology analysis by atomic force microscopy (AFM) showed that the membrane surface roughness increased with the added SMA amount. The results of water contact angle, water absorbance measurements and static protein adsorption experiments revealed that the surface enrichment of SMA endowed PES/SMA blend membranes with significantly improved surface hydrophilicity and protein-adsorption resistance.

[Reduction of CD44 expression results in growth inhibition of human nasopharyngeal carcinoma cell CNE-2L2 in vitro]

OBJECTIVE

To study the effect of the inhibition of CD44 gene expression on the growth of human nasopharyngeal carcinoma cell CNE-2L2 in vitro.

METHODS

CD44 gene expression in cells was suppressed by siRNA which was introduced into cells through retrovirus infection. Integration of siRNA into genomic DNA was examined by genomic PCR. CD44 gene expression in cells was detected by Western blot analysis. Cell growth in vitro was assayed using Cell Titer 96 AQueous One Solution Cell Proliferation Assay kit Promega. Cells were stained with propidium iodium and cell DNA content was detected upon a flow cytometer.

RESULTS

siRNA was integrated into genomic DNA of host cells. The 4 cell pools integrated with one of the 4 siCD44s showed a significant inhibition of CD44 gene expression comparing to the controls, the wild type cell and the cell pool integrated with siegfp. The cell pools integrated with siCD44-1 or siCD44-2 showed the most profound inhibition. Growth of these 2 cells in vitro was compared to that of the controls and was found to be significantly inhibited. Cell DNA content analysis indicated 44.4%, 45.5%, 53.9%, and 53.3% in G0/G1 phase; 39.3%, 40.0%, 27.1%, and 28.2% in S phase; and 16.3%, 14.5%, 19.0%, and 18.5% in G2/M phase for the wild type cell, the cell pool integrated with siegfp, the cell pools integrated with siCD44-1, and the cell pools integrated with siCD44-2, respectively.

CONCLUSION

Reduction in CD44 expression inhibit the growth of CNE-2L2 cell and affects the development of cells from G0/G1 into S phase, but may somehow promote cells to develop from S into G2/M phase.

Meningitis due toPrototheca wickerhamii: rare case in China

A rare case of Prototheca wickerhamii meningitis is reported in a patient without any underlying immunodeficient condition. Wet-mount microscopy and culture of cerebral spinal fluid specimens, along with temperature resistance, cycloheximide tolerance, carbohydrates assimilation, including API 20C AUX tests of the isolated etiologic agent were performed. In addition, transmission and scanning electron microscopy studies and in vitro antifungal susceptibility tests were conducted. Through the combination of these investigations, the isolate was identified as P. wickerhamii and the patient was successfully treated with intravenous amphotericin B and itraconazole. This is the first detailed report of meningitis caused by P. wickerhamii in China.

Structure-based 3D-QSAR studies on thiazoles as 5-HT3 receptor antagonists

Structure-based 3D-QSAR studies were performed on 20 thiazoles against their binding affinities to the 5-HT(3) receptor with comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA). The thiazoles were initially docked into the binding pocket of a human 5-HT(3A) receptor homology model, constructed on the basis of the crystal structure of the snail acetylcholine binding protein (AChBP), using the GOLD program. The docked conformations were then extracted and used to build the 3D-QSAR models, with cross-validated r2omega values 0.785 and 0.744 for CoMFA and CoMSIA, respectively. An additional five molecules were used to validate the models further, giving satisfactory predictive r2 values of 0.582 and 0.804 for CoMFA and CoMSIA, respectively. The results would be helpful for the discovery of new potent and selective 5-HT(3) receptor antagonists.

Passive sensitization increases histamine-stimulated calcium signaling and NF-kappaB transcription activity in bronchial epithelial cells

AIM

To find out if the two aspects of asthma (chronic airway inflammation and bronchial hyperresponsiveness) are related to hypersensitivity of calcium signaling in bronchial epithelial cells.

METHODS

Porcine bronchial epithelial cells (PBEC) were divided into sensitized (S) and non-sensitized (N) groups. In group S, the cells were preincubated with serum from ovalbumin sensitized guinea pigs. In group N, the cells were preincubated with serum from nonsensitized guinea pigs. Single cell calcium imaging and ELISA-based NF-kappaB activity were used to evaluate the histamine-stimulated intracellular free calcium level and NF-kappaB activity, respectively.

RESULTS

First, 0.1 micromol/L histamine could induce [Ca(2+)](i) oscillations in PBEC of group S, but not in group N. Second, 1 micromol/L histamine could induce [Ca(2+)](i) oscillations of PBEC in both group S and group N. The [Ca(2+)](i) oscillation frequency of PBEC was significantly higher in group S than in group N, though the [Ca(2+)](i) oscillation amplitude showed no difference between the two groups. Finally, when 10 micromol/L histamine was used to stimulate PBEC, a transient initial increase followed by a sustained elevation (FSE) of [Ca(2+)](i) was observed in PBEC in both groups. The amplitude of the FSE of [Ca(2+)](i) in PBEC was significantly higher in group S than in group N. The subsequent NF-kappaB activity was in accordance to the calcium oscillation frequency evoked by histamine, but not to the amplitude.

CONCLUSION

It was suggested that the increased sensitivity of calcium signaling in bronchial epithelial cells might contribute to the exorbitant inflammation or increased susceptibility in asthmatic airway epithelial cells.

Identification and expression analysis of alternatively spliced isoforms of human interleukin-23 receptor gene in normal lymphoid cells and selected tumor cells

Interleukin 23 (IL-23) is a new member of the IL-12 family that plays a critical role in promoting the proliferation of memory T helper 1 cells. The heterodimerized IL-23 receptor is composed of a shared IL-12 receptor beta 1 (IL-12Rbeta1) and an IL-12Rbeta2-related molecule called IL-23R. The standard form of IL-23R is encoded by at least 12 exons. Here, we demonstrate that at least six spliced isoforms of IL-23R (IL-23R1 to 6) can be generated through alternative splicing. The splicing strategies for the IL-23R gene are complicated and most often result in the deletion of exon 7 and/or exon 10. Translation prediction revealed that these spliced variants result in either premature termination to give rise to a diverse form of receptor ectodomain, or a frameshift to generate various lengths of the IL-23R endodomain. Differential expressions of IL-23R spliced variants are observed in natural killer and CD3+ CD4+ T cells. The expressions of these spliced variants are also prevalently and complicatedly regulated in tumor cell lines. Interestingly, only IL-23R2 and/or IL-23R4 variants are predominantly detected in certain human lung carcinomas, but not in their resected normal margin tissues. Thus, our results indicate that the regulation of alternative splicing on the IL-23R gene is complicated, and the preferential expression of certain IL-23R spliced variants may be a contributive factor to the pathogenesis of certain cancers.

Inhibition of 6A8 alpha-mannosidase gene expression resulted in telomere length shortening in nasopharyngeal carcinoma cell CNE-2L2

Telomere length shortening was observed in the nasopharyngeal carcinoma cell CNE-2L2 when 6A8 alpha-mannosidase expression was inhibited by antisense 6A8 DNA. Transduction with mock or an irrelevant DNA did not affect the telomere length in the carcinoma cells. Telomerase activity and mRNA transcription of TRF 1 and 2 were not changed in the cells treated with antisense 6A8. The Con A binding test showed an enhancement on the proteins isolated from the cells treated with antisense 6A8, but not on those from mock- or irrelevant DNA-treated cells. The data imply an association between glycosylation modification with telomere shortening in antisense 6A8-treated cells.

Effects of several antifungal drug combinations against clinical and environmental isolates of Cryptococcus neoformans from China. Effekte verschiedener Antimykotika-Kombinationen gegen klinische und Umgebungsisolate von Cryptococcus neoformans aus China

The in vitro interactions of caspofungin (CSP) with terbinafine (TRB) and ravuconazole (RVC) with 5-fluorocytosine (5-FC) were tested against 82 clinical and environmental isolates of Cryptococcus neoformans from China. The interaction of CSP with TRB proved synergistic against those isolates with a CSP MIC < or =2 microg ml-1 (5% of the isolates), additive against 42% of the isolates and indifferent against 53%. The effects of RVC with 5-FC were synergistic, additive or indifferent against 8%, 26% and 67% of the isolates, respectively. No antagonistic effects were found among any of the drugs. The combinations of CSP with TRB and RVC with 5-FC may display beneficial effects in a strain-dependent manner, while in no case showed antagonistic effects. These data might be of use to design safer and more efficient treatments for patients with cryptococcosis and warrant further evaluation.

Case Reports. Pulmonary cryptococcosis associated with cryptococcal meningitis in non-AIDS patients

We report four cases of pulmonary cryptococcosis associated with cryptococcal meningitis in non-HIV infected patients. All four patients had no apparent symptoms and signs of focal lesions that necessitate evaluation for the pulmonary lesion. Two out of four patients had radiologic evidence of pulmonary cavitation and mass lesions simultaneously, an uncommon finding in non-AIDS patients. Diagnostic and therapeutic problems of pulmonary cryptococcosis associated with cryptococcal meningitis are discussed.

[Growth inhibition of human nasopharyngeal carcinoma cell CNE-2L2 caused by suppression of 6A8 alpha-mannosidase expression]

OBJECTIVE

To study the relationship between 6A8 alpha-mannosidase expression and growth of CNE-2L2 cells, a human nasopharyngeal carcinoma cell line.

METHODS

Recombinant adeno-associated virus vector (rAAV) was used as a mediator to transfer an antisense or a sense fragment of 6A8 cDNA into CNE-2L2 cells. 6A8 alpha-mannosidase expression was detected by means of mAb 6A8a staining, alpha-mannosidase activity assay and ConA binding test. Cell growth was examined by means of MTT and colony formation. Tumor growth at the inoculated site of the cells in nude mice was detected after 8 weeks.

RESULTS

Transduction of antisense 6A8 could reduce the expression of 6A8 alpha-mannosidase. In comparison to those in controls, the wild type, the mock-transduced and the sense 6A8-transduced cells, the MTT value, the colony number formed and the tumor weight grown at the inoculated site of cells were significantly decreased in the antisense 6A8-transduced cells (P < 0.001).

CONCLUSION

Decreased expression of 6A8 alpha-mannosidase caused an inhibition of CNE-2L2 cell growth.

[6A8 alpha-mannosidase catalyzes p-nitrophenyl-alpha-D-mannopyranoside]

OBJECTIVE

To confirm the alpha-mannosidase nature of the protein encoded by 6A8 cDNA.

METHODS

1) To construct a full-length 6A8 cDNA based on the three cloned DNA fragments by means of gene recombinant technique; 2) To insert the 6A8 cDNA into eukaryotic expression vector pCDI; 3) To transfect the recombinant pCDI-6A8 into COS-7 cells; 4) To characterize the nature of the protein encoded by 6A8 cDNA by means of enzymic activity assay and Western blotting assay.

RESULTS

The constructed 6A8 cDNA was the right cDNA in sequence. The enzymetic activity of the homogenate of COS-7 cells transfected with pCDI-6A8 was 3-4 times higher than that of the cells transfected with the mock or the wild cells. The enzymetic reaction could not be inhibited by swainsonine. Western blot showed a band of 120,000 recognized by mAb 6A8. The band in the cells transfected with pCDI-6A8 cDNA was much darker than that in the cells transfected with the mock or in the wild cells.

CONCLUSION

The protein encoded by 6A8 cDNA is a kind of alpha-mannosidase, which belongs to type II alpha-mannosidase.

Long-term expression of a transferred gene in Epstein-Barr virus transformed human B cells

Delivering a gene into the Epstein-Barr virus (EBV)-transformed B cells is useful in studying effects of the gene on B-cell functions. However, although people have been able to efficiently transfer genes into and get them expressed in B-lympho blastoid cells for a time probably long enough to kill the cells using vectors harbouring oriP, the expression time of the delivered gene is not long enough in order to study the gene function in B cells. To solve this problem, we constructed an adeno-associated virus (AAV) plasmid pAGX(+) based on plasmids pSub201 and pRc/CMV. We developed and packaged recombinant AAV (rAAV) expression vectors containing an antisense or a sense DNA fragment of 6A8 cDNA encoding a human alpha-mannosidase, or an antisense fragment of 5D4 cDNA encoding a human cell membrane protein, or EYFP DNA. EBV-transformed B cell SKW6 and 3D5 were transduced with those rAAV or the mock. Transduction with the rAAV-EYFP showed an infection frequency of 64 +/- 3.5% and 58 +/- 6.2% for SKW6 and 3D5 cell, respectively. Genomic polymerase chain reaction (PCR) for neoR gene indicated an integration of the transferred gene into the host DNA. After being cultured and propagated for over 12 months, the cells were detected for the expression of the transferred gene. The RT-PCR, enzymatic assay and Con A binding test demonstrated an inhibition of 6A8 alpha-mannosidase in both SKW6 and 3D5 cells transduced with the antisense 6A8 DNA. Immunofluorescence staining with monoclonal antibodies (MoAb) 5D4 showed a reduction of the 5D4 protein expression on both the cells transduced with the antisense 5D4 DNA. The DNA fragmentation assay showed a resistance of the cells with 6A8 alpha-mannosidase inhibition to apoptosis induction by anti-Fas antibody. The data indicate that the AAV vector pAGX(+) can efficiently introduce genes into EBV-transformed B cells and the delivered gene can be expressed in the cells for more than 12 months which may be long enough for the study of gene functions in B cells.

Cloning, expression and characterization of a cDNA (6A8) encoding a novel human alpha-mannosidase

A 3300-bp cDNA (6A8) has been isolated from a human tonsil cell lambdagt11 cDNA library (GenBank accession number: AF044414). The 6A8 gene is localized on human chromosome 13q31-32. Its cDNA has an open reading frame from position 57 bp to 3243 bp, encoding a 1062 amino-acid polypeptide. The sequence of the polypeptide has 89% identity to rat liver ER alpha-mannosidase. Homogenates of COS-7 cells transfected with 6A8 cDNA showed an enhanced enzymatic activity with p-nitro-phenyl-alpha-D-mannopyranoside, which was not inhibited by swainsonine. These data suggest that 6A8 alpha-mannosidase belongs to the class II alpha-mannosidase. Western blot analysis showed a band for 6A8 cDNA encoded protein of approximately 120 kDa. Northern blot analysis revealed two 6A8 mRNA transcripts with different tissue distribution. Enhanced concanavalin A (ConA) binding to CNE-2L2 cells transfected with a reverse 6A8 DNA was observed, indicating that the 6A8 protein is an important cellular alpha-mannosidase.

Mitochondrial Ca(2+)homeostasis in the regulation of apoptotic and necrotic cell deaths

Using distinct models of apoptosis and necrosis, we have investigated the effect of mitochondrial Ca(2+)(Ca(m)) homeostasis in the regulation of cell death in neuroblastoma cells as well as cardiac myocytes. The steady state level of Ca(m)was determined as the FCCP-releasable Ca(2+). Culturing cells with low concentration of extracellular Ca(2+)(Ca(o)) or with EGTA triggered an early reduction in both the Ca(m)store and the membrane potential (DeltaPsi(m)). This was followed by the detection of cytochrome c release, caspase activation, and apoptosis. Inhibitors of the mitochondrial permeability transition pore such as cyclosporin A and Bcl-2 blocked the release of Ca(m)and inhibited apoptosis. In contrast, mitochondrial Ca(2+)overload resulted in necrotic cell death. Culturing cells in the presence of excess Ca(o)led to increased Ca(m)load together with a decrease of DeltaPsi(m)that reached maximum at 1 h, with necrosis occurring at 2 h. While the decline of Ca(m)and DeltaPsi(m)was a coupled reaction for apoptosis, this relationship was uncoupled during necrosis. Clonazepam, a relatively specific inhibitor of the mitochondrial Na/Ca exchanger, was able to protect the cells from necrosis by reducing Ca(m)overload. Importantly, combination of clonazepam and cyclosporin showed a cooperative effect in further reducing the Ca(m)overload and abolished cell death. The data imply the participation of Ca(m)homeostasis in the regulation of apoptosis and necrosis.

Activity changes of ATP synthase and adenylate kinase in rat-liver mitochondria during the early phase after burn injury

Using succinate as a substrate, the activities of ATP synthase and adenylate kinase in liver mitochondria of male Sprague-Dawley rats 30 min after 20 per cent full skin thickness burns were increased in comparison with the sham burn rats, suggesting that these two enzymes might contribute to the increased rates of ATP formation and oxidative phosphorylation coupling during the early phase after burn injury.

[Phenotype analysis of peripheral blood T lymphocytes from SLE patients by flow cytometry]

Phenotype of OKT3, OKT4 and OKT8 markers on surface of peripheral blood T lymphocytes from 31 SLE patients were analyzed with a flow cytometer and the results were compared with those of T cells from 36 normal controls. The results showed that the rates of OKT3+ and OKT4+ cells were within the normal range, while that of OKT8+ cells (44.52 +/- 12.07%) was significantly higher than normal (30.39 +/- 6.06%, P less than 0.01). Besides, the OKT4+/OKT8+ ratio in patients (0.69 +/- 0.24) was lower than that of normal controls (1.06 +/- 0.28, P less than 0.01), 5/13 (38.5%) cases with kidney lesion showing obvious decrease of OKT4+/OKT8+ ratio, while 1/18 cases (5.56%) without kidney lesion also showing such decrease.

Selective effects of cyclophosphamide therapy on activation, proliferation, and differentiation of human B cells

The immune function of B lymphocytes from 12 patients with nonneoplastic immune-mediated diseases receiving chronic low-dose (2 mg/kg per d) cyclophosphamide (CY) was evaluated. There was a selective and differential suppressive effect of CY therapy on the various stages of the B cell cycle including activation, proliferation, and differentiation. The proliferative responses to Staphylococcus aureus Cowan strain I (SAC) and mitogenic concentrations of anti-mu were suppressed. In contrast, B cells that have been presumably activated in vivo proliferated with a normal pattern when exposed to B cell growth factor in vitro. Chronic low-dose CY therapy also suppressed B cell differentiation. Secretion of immunoglobulin by B cells following in vitro triggering with SAC and a T cell supernatant was suppressed in CY-treated patients. Moreover, differentiation of the large in vivo-activated B cells (which do not require an in vitro activation signal) in the presence of appropriate T lymphocyte supernatant was also suppressed. This selective suppression of B cell function at multiple points in the B cell cycle may be responsible for the efficacy of CY therapy in certain antibody and immune complex-mediated diseases.