Localization of CD26/DPPIV in nucleus and its nuclear translocation enhanced by anti-CD26 monoclonal antibody with anti-tumor effect

<p>Abstract</p> <p>Background</p> <p>CD26 is a type II, cell surface glycoprotein known as dipeptidyl peptidase (DPP) IV. Previous studies have revealed CD26 expression in T cell leukemia/lymphoma and malignant mesothelioma, and an inhibitory effect of anti-CD26 monoclonal antibody (mAb) against the growth of CD26+ cancer cells in vitro and in vivo. The function of CD26 in tumor development is unknown and the machinery with which the CD26 mAb induces its anti-tumor effect remains uncharacterized.</p> <p>Results</p> <p>The localization of CD26 in the nucleus of T cell leukemia/lymphoma cells and mesothelioma cells was shown by biochemical and immuno-electron microscopic analysis. The DPPIV enzyme activity was revealed in the nuclear fraction of T cell leukemia/lymphoma cells. These expressions of intra-nuclear CD26 were augmented by treatment with the CD26 mAb, 1F7, with anti-tumor effect against the CD26+ T cell leukemia/lymphoma cells. In contrast, the CD26 mAb, 5F8, without anti-tumor effect, did not augment CD26 expressions in the nucleus. Biotin-labeled, cell surface CD26 translocated into the nucleus constantly, and this translocation was enhanced with 1F7 treatment but not with 5F8.</p> <p>Conclusion</p> <p>These results indicate that the intra-nuclear CD26 which moves from plasma membrane may play certain roles in cell growth of human cancer cells.</p

Synergistic Pathogenic Effects of Combined Mouse Monoclonal Anti-Desmoglein 3 IgG Antibodies on Pemphigus Vulgaris Blister Formation

Pemphigus vulgaris (PV) is an autoimmune blistering disease caused by anti-desmoglein 3 (Dsg3) IgG antibodies. Previously, we generated an active mouse model for PV by adoptive transfer of splenocytes from immunized or naive Dsg3−/− mice. In this study, we isolated 10 anti-Dsg3 IgG mAbs (NAK-series) from PV model mice generated by transfer of naive Dsg3−/− splenocytes. We characterized their epitopes using domain-swapped and point-mutated Dsg1/Dsg3 molecules and examined their pathogenic activities in blister formation in three different assays. In a passive transfer model using neonatal mice, eight of 10 NAK mAbs showed pathogenic activity when injected together with half the minimum pathogenic dose of anti-Dsg1 IgG autoantibodies from pemphigus foliaceus (PF) patients. None of the mAbs could induce the PV phenotype when individual hybridoma clones were inoculated by peritoneal injection into adult Rag2−/− mice. NAK mAbs displayed a range of potency in an in vitro dissociation assay using primary cultured mouse keratinocytes. Interestingly, when multiple hybridoma clones recognizing different epitopes were inoculated in combination, recipient mice developed the PV phenotype. In vitro dissociation assays confirmed that combined NAK mAbs had synergistic pathogenic effects. These findings indicate that although an individual anti-Dsg3 IgG is not sufficient to cause blistering in adult mice, several together can induce the PV phenotype. These mAbs will provide a valuable tool to investigate the molecular mechanisms of blister formation, mimicking the effects of the polyclonal IgG antibodies found in patients

Genome structure of the Lactobacillus temperate phage Φg1e: the whole genome sequence and the putative promoter/repressor system

The complete genome sequence of a Lactobacillus temperate phage Φg1e was established. The double-stranded DNA is composed of 42 259 bp, and encodes for sixty-two possible open reading frames (ORF) as well as several potential regulatory sequences. Based on comparative analysis with other related proteins of the Lactobacillus and Lactococcus phages as well as the Escherichia coli phages (such as lambda), functions were putatively assigned to several Φg1e ORFs: cng and cpg (encoding for repressors), hel (helicase), ntp (NTPase), and several ORFs (e.g., minor capsid proteins). An about 1000-bp DNA region of Φg1e containing cpg and cng was inferred to function as a promoter/repressor system for the Φg1e lysogenic and lytic pathway

Essential roles of DC-derived IL-15 as a mediator of inflammatory responses in vivo

Interleukin (IL)-15 is expressed in a variety of inflammatory diseases. However, the contribution of dendritic cell (DC)–derived IL-15 to the development of diseases is uncertain. Using established models of Propionibacterium acnes (P. acnes)– and zymosan-induced liver inflammation, we observed granuloma formation in the livers of wild-type (WT) and RAG-2−/− mice but not in those of IL-15−/− mice. We demonstrate that this is likely caused by an impaired sequential induction of IL-12, IFN-γ, and chemokines necessary for monocyte migration. Likewise, lethal endotoxin shock was not induced in P. acnes– and zymosan-primed IL-15−/− mice or in WT mice treated with a new IL-15–neutralizing antibody. In both systems, proinflammatory cytokine production was impaired. Surprisingly, neither granuloma formation, lethal endotoxin shock, nor IL-15 production was induced in mice deficient for DCs, and adoptive transfer of WT but not IL-15−/− DCs restored the disease development in IL-15−/− mice. Collectively, these data indicate the importance of DC-derived IL-15 as a mediator of inflammatory responses in vivo

Overexpression of CD26/DPPIV in mesothelioma tissue and mesothelioma cell lines

Mesothelioma, a highly aggressive cancer with poor prognosis and refractory to currently available therapies show increasing trends of its incidence in Japan and other developing countries. Although surgery is a gold standard for patients with early mesothelioma, most patients with advanced disease are not suitable for surgical resection and have option of palliative chemotherapy alone. One of the new treatment strategies for mesothelioma, the humanized anti-CD26 monoclonal antibody therapy is under development. CD26, a 110-kDa transmembrane glycoprotein with known dipeptidyl peptidase IV activity, plays a role in tumor development and its expression was reported in various human malignancies. This study determined the preliminary selection criteria for humanized monoclonal anti-CD26 antibody therapy. Eighty-one epithelioid (49 differentiated and 32 less differentiated), 34 sarcomatoid, 19 biphasic mesothelioma and 8 mesothelioma cell lines were immunohistochemically examined using 8 different commercially available anti-CD26 antibodies for membranous and cytoplasmic expression. The cytoplasmic expression of CD26 was observed in all histological types of mesothelioma, while the membranous expression of CD26 was found in 88% of differentiated and 69% of less differentiated epithelioid mesothelioma, and none of sarcomatoid mesothelioma with anti-CD26 antibodies with rabbit polyclonal anti-DPP4 antibody and similar results were also obtained with goat polyclonal anti-DPP4/CD26 antibody. These antibodies absorbed with soluble human CD26 proteins do not show CD26 expression in mesothelioma tissue, suggesting these two antibodies localize true CD26 protein. Seven mesothelioma cell lines, including sarcomatoid types, also showed membranous expression of CD26 in cellblock preparation.CD26 vector transfection to CD26-negative MSTO-211H cells showed membranous expression of CD26 by flow cytometry, but not in tumor developed in NOD/SCID mice with inoculation of CD26 vector transfected MSTO-211H cells. We found that both ra