Characterization of the First Genome of Porcine mastadenovirus B (HNU1 Strain) and Implications on Its Lymphoid and Special Origin

Virologica Sinica - Porcine adenoviruses (PAdVs) are classified into three species, PAdV-A, PAdV-B, and PAdV-C. The genomes of PAdV-A and PAdV-C have been well characterized. However, the genome of...     

Trypanosoma cruzi: alteration in the lymphoid compartments following interruption of infection by early acute benznidazole therapy in mice

Disability and mortality as consequence of Chagas disease is enormous in South America. Recently, the success of the trypanocidal treatment with benznidazole, the only available drug, has been associated with the host immune response. In the current study, the impact of benznidazole administration immediately after the experimental infection with Trypanosoma cruzi was evaluated in the main lymphocyte populations in lymphoid organs. Untreated mice displayed enlargement of spleen and lymph node related to the increased frequency of T and B lymphocytes, respectively. An intense thymus involution with the depletion of CD4(+)CD8(+) double-positive thymocytes also occurred. Benznidazole treatment led to a partial reversion of the spleen and lymph node enlargement related to changes in the frequency of lymphocyte subsets due to infection. Prevention of thymus involution was achieved, with the profile of thymocyte subsets similar to that of non-infected mice. The parasitic load at the onset of T. cruzi infection seems critical to trigger immune system activation.     

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-12Rβ1) and an IL-12Rβ2-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.     

Differential effect of appendectomy and tonsillectomy on anti-Kudoa sp. antibodies in patients with MALTectomy

We found an association between tonsillectomized patients and subsequent appendicitis. We also observed that MALTectomy significantly decreased secretory IgA levels in serum of patients, being this decrease more pronounced when both operations (tonsillectomy and appendectomy) had been performed. The elevated humoral responses detected previously by us in BALB/c mice immunized with Kudoa sp. pseudocyst extracts and the high IgG1 and IgE levels induced by the oral administration of Kudoa sp. pseudocysts to BALB/c mice showed the possible immunopathological effects in man from the ingestion of Kudoa sp. infected fish. We use the ELISA method to investigate the possible relationship between MALTectomy (tonsillectomy and appendectomy) and specific antibody levels to Kudoa sp. Both anti-Kudoa sp. specific antibody levels and the number of patients that recognized Kudoa sp. antigens were greater in tonsillectomy patients when compared to the control and the other studied groups (appendectomized and appendectomized + tonsillectomies patients). Tonsillectomy was associated to a switch in the class of immunoglobulins involved in these responses and these responses may be abrogated by appendectomy. Tonsils and appendix may respond in different ways to Kudoa sp. antigens and these different reactions may be involved in some immunopathological reactions.     

A novel medium for the development of in vitro cell culture system from Penaeus monodon

Lack of a valid shrimp cell line has been hampering the progress of research on shrimp viruses. One of the reasons identified was the absence of an appropriate medium which would satisfy the requirements of the cells in vitro. We report the first attempt to formulate an exclusive shrimp cell culture medium (SCCM) based on the haemolymph components of Penaeus monodon prepared in isosmotic seawater having 27 ‰ salinity. The SCCM is composed of 22 amino acids, 4 sugars, 6 vitamins, cholesterol, FBS, phenol red, three antibiotics, potassium dihydrogen phosphate and di-sodium hydrogen phosphate at pH 6.8–7.2. Osmolality was adjusted to 720 ± 10 mOsm kg⁻¹ and temperature of incubation was 25 ºC. The most appropriate composition was finally selected based on the extent of attachment of cells and their proliferation by visual observation. Metabolic activity of cultured cells was measured by MTT assay and compared with that in L-15 (2×), modified L-15 and Grace’s insect medium, and found better performance in SCCM especially for lymphoid cells with 107 % increase in activity and 85 ± 9 days of longevity. The cells from ovary and lymphoid organs were passaged twice using the newly designed shrimp cell dissociation “cocktail”.     

Identification of novel triazole inhibitors of Wnt/β-catenin signaling based on the Niclosamide chemotype

Dysregulation of the Wnt signaling pathway is an underlying mechanism in multiple diseases, particularly in cancer. Until recently, identifying agents that target this pathway has been difficult and as a result, no approved drugs exist that specifically target this pathway. We reported previously that the anthelmintic drug Niclosamide inhibits the Wnt/β-catenin signaling pathway and suppresses colorectal cancer cell growth in vitro and in vivo. In an effort to build on this finding, we sought to discover new Wnt/β-catenin inhibitors that expanded the chemotype structural diversity. Here, we asked a specific SAR question unresolved in previous SAR studies of Niclosamide’s inhibition of Wnt/β-catenin signaling to identify a new structural class of Wnt/β-catenin signaling inhibitors based on a triazole motif. Similar to Niclosamide, we found that the new triazole derivatives internalized Frizzled-1 GFP receptors, inhibited Wnt/β-catenin signaling in the TOPflash assay and reduced Wnt/β-catenin target gene levels in CRC cells harboring mutations in the Wnt pathway. Moreover, in pilot SAR studies, we found the Wnt/β-catenin SAR trends in the anilide region were generally similar between the two chemical classes of inhibitors. Overall, these studies demonstrate the ability to use the SAR of the Niclosamide salicylanilide chemical class to expand the structural diversity of Wnt/β-catenin inhibitors.     

Interdigitating cells in the lymphoid tissues of bovine fetuses and calves

Summary Electron-microscopic studies of lymphoid tissues from bovine fetuses and from calves disclosed a non-lymphoid cell type in the thymus-dependent zones of secondary lymphoid tissues and in the thymus that is distinguishable from reticulum cells, epithelial and endothelial cells, and macrophages. Based on morphological and topographical criteria, the cell is identified as the interdigitating cell. In addition, studies of the tissues of normal and virus-challenged fetuses, and of conventionally reared calves, indicated that the interdigitating cells originate from monocytoid cells, which undergo differentiation in the thymus-dependent zones during an immune response.     

A novel antigen is common to the dome epithelium of gut- and bronchus-associated lymphoid tissues

Summary The dome epithelium (DE) covering bronchus- and gut-associated lymphoid tissues (BALT and GALT) is composed of columnar cells, groups of lymphocytes, M cells, and pre-M cells. Although the cell biology and immunologic processes of this tissue are likely important in the afferent arm of secretory immune responses, virtually nothing is known about biochemical constituents of the DE. Therefore, a monoclonal antibody, 30E5, was used to study the distribution of a novel antigen, common to dome epithelia of GALT and BALT. 30E5 was secreted by a hybridoma, prepared by fusing murine splenocytes, immunized against dome epithelial cells, with P3×68/Ag8 myeloma cells. Reactivity of antigens was defined by indirect immunocytochemistry on sections of rabbit tissues or with dissociated epithelial cells. In situ, 30E5-reactive antigen circumscribed each group of dome epithelial lymphocytes, most or all of which were T cells, in rabbit appendix, sacculus rotundus, cecal patch, Peyer's patch, and BALT. In the DE this antigen was associated with the apical surface and the supranuclear or perinuclear regions of epithelial cells, but it was not associated with epithelial cells of villi, epithelium, or with individual lymphocytes. In peripheral lymph nodes, spleen, and in domes and follicles of GALT or BALT, 30E5-reactive antigen was visualized in linear wisps, primarily in regions populated by thymocytes. In other adult tissues, 30E5-reactive antigen was associated with involuntary muscle, myoepithelial cells of lactating mammary gland and with what appeared to be neural dendrites; but it was not found in epithelia other than DE. In neonatal rabbit appendix, this antigen first appeared in the upper dome epithelium two days after birth, a period coinciding with T cell infiltration and M cell maturation. The histologic distribution of 30E5-reactive antigen suggested that it might be a contractile filament, a receptor, or a differentiation antigen. Since 30E5 was associated with DE of both GALT and BALT, results support the concept of a molecule common to all mucosa-associated lymphoid tissues.In conducting the research described in this report, the investigators adhered to standards set forth in the Guide for the Care and Use of Laboratory Animals (NIH Publication 85-23) as promulgated by the Committee on Care and Use of Laboratory Animals of the Institute of Laboratory Animal Resources, National Research Council, USALimited quantities of ascites containing monoclonal antibody 30E5 will be distributed to interested investigators until such time as the hybridoma is available from American Type Culture CollectionAbbreviations ABC avidin-biotin-horseradish peroxidase complex - BALT bronchus-associated lymphoid tissues - DMEM Dulbecco's modified Eagle medium - GALT gut-associated lymphoid tissues - DE dome epithelium - DEL dome epithelial lymphocytes - MAb monoclonal antibody - MALT mucosal-associated lymphoid tissues The views of the authors expressed here do not purport to reflect the position of the Department of the Army or the Department of Defense Send offprint requests to: Department of Experimental Pathology, Division of Pathology, Walter Reed Army Institute of Research, Washington, D.C. 20307-5100, USA     

Precocious development of lectin (Ulex europaeus agglutinin I) receptors in dome epithelium of gut-associated lymphoid tissues

Summary Dome epithelium (DE), the tissue covering lymphoid domes of gut-associated lymphoid tissues, was examined in both adult and neonatal rabbit appendix or sacculus rotundus to determine if dome epithelial cells matured earlier than epithelial cells covering adjacent villi. The localization of well-differentiated epithelial cells in rabbit gut-associated lymphoid tissues (GALT) was accomplished histochemically by use of molecular probes: fluorescein isothiocyanate or horseradish peroxidase conjugates of Ulex europaeus agglutinin I (UEA), a lectin specific for terminal L-fucose molecules on certain glycoconjugates. The villus epithelial cells of newborn and 2-, 5-, or 10-day-old rabbits did not bind UEA, but between the twelfth and fifteenth days of postnatal life, UEA receptors were expressed by well-differentiated villus epithelial cells. In contrast to villus epithelium, DE in appendix and sacculus rotundus of neonatal rabbits expressed UEA receptors two days after birth, a feature that distinguished the DE of neonatal GALT for the next two weeks. In adult rabbits, UEA receptors were associated with dome epithelial cells extending from the mouths of glandular crypts to the upper domes; in contrast to the domes, UEA receptors were only present on well-differentiated epithelial cells at the villus tips. Results suggested that in neonatal rabbits most dome epithelial cells developed UEA receptors shortly after birth, reflecting precocious development of DE as compared to villus epithelium. In adult rabbit dome epithelium UEA receptors appeared on dome epithelial cells as they left the glandular crypts, representing accelerated epithelial maturation.Abbreviations DE dome epithelium - DEL dome epithelial lymphocytes - FITC fluorescein isothiocyanate - HRP horseradish peroxidase - PBS phosphate-buffered saline - PBS-CaMg PBS containing calcium and magnesium ions - UEA Ulex europaeus agglutinin I The views of the authors expressed here do not purport to reflect the position of the Department of the Army or the Department of DefenseIn conducting the research described in this report, the investigators adhered to standards set forth in the Guide for the Care and Use of Laboratory Animals (NIH Publication 85-23) as promulgated by the Committee on Care and Use of Laboratory Animals of the Institute of Laboratory Animal Resources, National Research Council, USA     

Characterization and identification of Tage4 as the murine orthologue of human poliovirus receptor/CD155

CD155 is a member of the immunoglobulin superfamily also known as the human receptor for poliovirus (PVR). Transmembrane glycoproteins related to CD155, the nectins, are well-characterized cell adhesion receptors displaying a high degree of sequence conservation across species. In contrast, CD155 belongs to the category of rapidly evolving genes wherefore a mouse CD155 gene distinguished by an affirmative extent of amino acid conservation as observed for nectins is absent. Consequently, the existing genetic evidence by itself is an inferior indicator to consider whether Tage4, a mouse orphan receptor, represents the murine orthologue of CD155. In the present study Tage4 cDNA was cloned from mouse lung and further characterized genetically. CD155 and Tage4 possess an identical genomic organization and reside in syntenic chromosomal regions. The Tage4 expression pattern was explored applying a newly generated antibody. Both receptors, CD155 in human and Tage4 in mouse, are expressed by intestinal epithelia as well as by follicle associated epithelium and follicular dendritic cells inside Peyer's patches of the gut associated lymphoid tissue. Furthermore, Tage4 lacks self-adhesion capacity but binds to vitronectin, two known features of CD155. These data indicate that Tage4 represents the functional orthologue of CD155 in mouse. Therefore, we suggest to rename Tage4 into rodent CD155.