Pseudoxanthomonas putridarboris sp. nov. isolated from rotten tree.

A Gram-staining-negative, rod-shaped, motile bacterium, designated WD12T, was isolated from a rotten tree at Chungbuk National University, South Korea. WD12T grew optimally at 30-37 °C and pH 7.0-7.5 and could assimilate arbutin and potassium-5-ketogluconate. The major cellular fatty acid were iso-C16 : 0, C16 : 0, cyclo C17 : 0, iso-C15 : 0, summed features 3 (comprising C16 : 1ω7c/iso-C15 : 0 2-OH) and anteiso-C15 : 0. The major polar lipids consisted of phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol. The major respiratory quinone was ubiquinone-8 (Q-8). The G+C content of the genomic DNA was 69.1 %. The results of phylogenetic and comparative analysis based on the 16S rRNA gene sequence indicated that WD12T formed a tight phylogenetic lineage with Pseudoxanthomonas mexicana AMX 26BT and Pseudoxanthomonas japonensis 12-3T of the the genus Pseudoxanthomonas in the family Xanthomonadaceae. Sequence similarity to other members of the genus Pseudoxanthomonasranged from 98.6 % (P. mexicana AMX 26BT) to 95.1 % (Pseudoxanthomonas taiwanensis CB-226T). DNA-DNA relatedness between WD12T and eight type strains of species of the genus Pseudoxanthomonasshowing more than 97 % 16S rRNA sequence similarity were 6±0-26±1 %. On the basis of the evidence from this polyphasic study, WD12T represents a novel species of the genus Pseudoxanthomonas, for which the name Pseudoxanthomonas putridarboris sp. nov. is proposed. The type strain is WD12T (=KACC 15045T=LMG 25968T).

Novel monoclonal antibody against beta 1 integrin enhances cisplatin efficacy in human lung adenocarcinoma cells.

The use of anti-beta 1 integrin monoclonal antibody in lung cancer treatment has proven beneficial. Here, we developed a novel monoclonal antibody (mAb), called P5, by immunizing mice with human peripheral blood mononuclear cells (PBMC). Its anti-tumor effect is now being tested, in a clinical phase III trial, in combinatorial treatments with various chemical drugs. To confirm that P5 indeed binds to beta 1 integrin, cell lysates were immunoprecipitated with commercial anti-beta 1 integrin mAb (TS2/16) and immunoblotted against P5 to reveal a 140 kDa molecular weight band, as expected. Immunoprecipitation with P5 followed by LC/MS protein sequence analysis further verified P5 antigen to be beta 1 integrin. Cisplatin treatment upregulated cell surface expression of beta 1 integrin in A549 cells, while causing inhibition of cell growth. When cells were co-treated with different concentrations of P5 mAb, the cisplatin-mediated inhibitory effect was enhanced in a dose-dependent manner. Our findings show that a combinatorial treatment of P5 mAb and cisplatin in A549 cells resulted in a 30% increase in apoptosis, compared to baseline, and significantly more when compared to either the cisplatin or P5 alone group. The entire peptide sequences in CDR from variable region of Ig heavy and light chain gene for P5 mAb are also disclosed. Together, these results provide evidence of the beneficial effect of P5 mAb in combinatorial treatment of human lung adenocarcinoma.

Characterization of Two Novel mAbs Recognizing Different Epitopes on CD43.

JL1, a specific epitope on CD43, is a potential biomarker for the diagnosis of acute leukemia. Although qualitative assays for detecting leukemia-specific CD43 exist, there is a need to develop quantitative assays for the same. Here, we developed two novel monoclonal antibodies (mAbs), 2C8 and 8E10, recognizing different epitopes on CD43. These clones are capable of pairing with YG5, another mAb against JL1 epitope, because they were selectively obtained using sandwich ELISA. Antigens recognized by 2C8 and 8E10 were confirmed as CD43 by western blotting using the CD43-hFC recombinant protein. When expression on various leukemic cell lines was investigated, 2C8 and 8E10 displayed a disparity in the distribution of the epitope. Enzyme assays revealed that these mAbs recognized a sialic acid-dependent epitope on CD43. Using normal thymus and lymph node paraffin-embedded tissues, we confirmed a difference in the epitopes recognized by the two mAbs that was predicted based on the maturity of the cells in the tissue. In summary, we developed and characterized two mAbs, 2C8 and 8E10, which can be used with YG5 in a sandwich ELISA for detecting leukemia-specific CD43.

Generation of 1E8 Single Chain Fv-Fc Construct Against Human CD59.

BACKGROUND: Therapeutic approaches using monoclonal antibodies (mAbs) against complement regulatory proteins (CRPs:i.e.,CD46,CD55 and CD59) have been reported for adjuvant cancer therapy. In this study, we generated a recombinant 1E8 single-chain anti-CD59 antibody (scFv-Fc) and tested anti-cancer effect.by using complement dependent cytotoxicity (CDC). METHODS: We isolated mRNA from 1E8 hybridoma cells and amplified the variable regions of the heavy chain (VH) and light chain (VL) genes using reverse-transcriptase polymerase chain reaction (RT-PCR). Using a linker, the amplified sequences for the heavy and light chains were each connected to the sequence for a single polypeptide chain that was designed to be expressed. The VL and VH fragments were cloned into the pOptiVEC-TOPO vector that contained the human CH2-CH3 fragment. Then, 293T cells were transfected with the 1E8 single-chain Fv-Fc (scFv-Fc) constructs. CD59 expression was evaluated in the prostate cancer cell lines using flow cytometry. The enhancement of CDC effect by mouse 1E8 and 1E8 scFv-Fc were evaluated using a cytotoxicity assay. RESULTS: The scFv-Fc constructs were expressed by the transfected 293T cells and secreted into the culture medium. The immunoreactivity of the secreted scFv-Fc construct was similar to that of the mouse 1E8 for CCRF-CEM cells. The molecular masses of 1E8 scFv-Fc were about 120 kDa and 55 kDa under reducing and non-reducing conditions, respectively. The DNA sequence of 1E8 scFv-Fc was obtained and presented. CD59 was highly expressed by the prostate cancer cell line. The recombinant 1E8 scFv-Fc mAb revealed significantly enhanced CDC effect similar with mouse 1E8 for prostate cancer cells. CONCLUSION: A 1E8 scFv-Fc construct for adjuvant cancer therapy was developed.

Characterization of Monoclonal Antibodies against Human Leukocyte Common Antigen (CD45).

BACKGROUND: The leukocyte common antigen (CD45) is a transmembrane-type protein tyrosine phosphatase that has five isoforms. METHODS: We generated seven murine mAbs against human CD45 by injecting cells from different origins, such as human thymocytes, PBMCs, and leukemic cell lines. By using various immunological methods including flow cytometry, immunohistochemistry, and immunoprecipitation, we evaluated the reactivity of those mAbs to CD45 of thymus as well as tonsil lysates. Furthermore, we transiently transfected COS-7 cells with each of gene constructs that express five human CD45 isoforms respectively, and examined the specificities of the mAbs against the transfected isoforms. RESULTS: In case of thymocytes, lymphocytes, and monocytes, all the seven mAbs demonstrated positive reactivities whereas none was reactive to erythrocytes and platelets. The majority of immune cells in formalin-fixed paraffin-embedded thymus and tonsil tissues displayed strong membranous immunoreactivity, and the main antigen was detected near 220 kDa in all cases. Among the mAbs, four mAbs (AP4, DN11, SHL-1, and P6) recognized a region commonly present in all the five isoforms. One mAb, YG27, recognized four isoforms (ABC, AB, BC, and O). Two mAbs, P1 and P14, recognized the isoforms that contain exon A encoded regions (ABC and AB). CONCLUSION: In this study, we confirmed that AP4, DN11, SHL-1, YG27 and P6, are mAbs reactive with the CD45 antigen whereas P1 and P14 are reactive with the CD45RA antigen.