We established long-term cell lines of cytotoxic T lymphocytes (CTL) specific for human T cell leukemia virus type I (HTLV-I) from peripheral blood lymphocytes (PBL) of a patient with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), an HTLV-I-carrier with Sjögren syndrome, and an asymptomatic HTLV-I-carrier, by repeated stimulation with autologous HTLV-I-infected T cells in vitro. CTL derived from the patient with HAM/TSP expressed CD8 antigen, and their function was restricted by HLA-A2. They showed cytotoxic effects predominantly against the target cells expressing HTLV-I p40tax among the autologous B cell lines infected with vaccinia recombinants containing various HTLV-I genes which served as targets. These data are consistent with the previously reported findings that fresh PBL of HAM/TSP patients contain p40tax-specific CTL activity. Furthermore, CTL derived from the patient with Sjögren syndrome without neurological involvement also demonstrated cytotoxicity predominantly to p40tax. The cytotoxicity to the target cells experimentally expressing p40tax was blocked by unlabeled HTLV-I-infected cells possessing HLA-A2. HTLV-I-specific cytotoxicity was also inhibited by unlabeled B cells bearing p40tax. Thus, HTLV-I p40tax-specific cytotoxicity is mediated by the major CTL population activated by native HTLV-I antigens in patients with HAM/TSP or Sjögren syndrome. In contrast to the CTL of these patients, CTL similarly induced from the asymptomatic HTLV-I-carrier, which were highly cytotoxic to autologous HTLV-I-infected T cells, did not show significant levels of cytotoxicity to autologous B cells expressing p40tax.(ABSTRACT TRUNCATED AT 250 WORDS)

The subcellular distributions and co-associations of the gap junction-forming proteins connexin 47 and connexin 32 were investigated in oligodendrocytes of adult mouse and rat CNS. By confocal immunofluorescence light microscopy, abundant connexin 47 was co-localized with astrocytic connexin 43 on oligodendrocyte somata, and along myelinated fibers, whereas connexin 32 without connexin 47 was co-localized with contactin-associated protein (caspr) in paranodes. By thin-section transmission electron microscopy, connexin 47 immunolabeling was on the oligodendrocyte side of gap junctions between oligodendrocyte somata and astrocytes. By freeze-fracture replica immunogold labeling, large gap junctions between oligodendrocyte somata and astrocyte processes contained much more connexin 47 than connexin 32. Along surfaces of internodal myelin, connexin 47 was several times as abundant as connexin 32, and in the smallest gap junctions, often occurred without connexin 32. In contrast, connexin 32 was localized without connexin 47 in newly-described autologous gap junctions in Schmidt-Lanterman incisures and between paranodal loops bordering nodes of Ranvier. Thus, connexin 47 in adult rodent CNS is the most abundant connexin in most heterologous oligodendrocyte-to-astrocyte gap junctions, whereas connexin 32 is the predominant if not sole connexin in autologous ("reflexive") oligodendrocyte gap junctions. These results clarify the locations and connexin compositions of heterologous and autologous oligodendrocyte gap junctions, identify autologous gap junctions at paranodes as potential sites for modulating paranodal electrical properties, and reveal connexin 47-containing and connexin 32-containing gap junctions as conduits for long-distance intracellular and intercellular movement of ions and associated osmotic water. The autologous gap junctions may regulate paranodal electrical properties during saltatory conduction. Acting in series and in parallel, autologous and heterologous oligodendrocyte gap junctions provide essential pathways for intra- and intercellular ionic homeostasis.

Gap junctions between glial cells in mammalian CNS are known to contain several connexins (Cx), including Cx26, Cx30 and Cx43 at astrocyte-to-astrocyte junctions, and Cx29 and Cx32 on the oligodendrocyte side of astrocyte-to-oligodendrocyte junctions. Recent reports indicating that oligodendrocytes also express Cx47 prompted the present studies of Cx47 localization and relationships to other glial connexins in mouse CNS. In view of the increasing number of connexins reported to interact directly with the scaffolding protein zonula occludens-1 (ZO-1), we investigated ZO-1 expression and Cx47/ZO-1 interaction capabilities in brain, spinal cord and Cx47-transfected HeLa cells. From counts of over 9000 oligodendrocytes labeled by immunofluorescence in various brain regions, virtually all of these cells were found to express Cx29, Cx32 and Cx47. Oligodendrocyte somata displayed robust Cx47-immunopositive puncta that were co-localized with punctate labeling for Cx32 and Cx43. By freeze-fracture replica immunogold labeling, Cx47 was abundant on the oligodendrocyte-side of oligodendrocyte/astrocyte gap junctions. By immunofluorescence, labeling for Cx47 along myelinated fibers was sparse in most brain regions, whereas Cx29 and Cx32 were previously found to be concentrated along these fibers. By immunogold labeling, Cx47 was found in numerous small gap junctions linking myelin to astrocytes, but not within deeper layers of myelin. Brain subcellular fractionation revealed a lack of Cx47 enrichment in myelin fractions, which nevertheless contained an enrichment of Cx32 and Cx29. Oligodendrocytes were immunopositive for ZO-1, and displayed almost total Cx47/ZO-1 colocalization. ZO-1 was found to co-immunoprecipitate with Cx47, and pull-down assays indicated binding of Cx47 to the second PDZ domain of ZO-1.Our results indicate widespread expression of Cx47 by oligodendrocytes, but with a distribution pattern in relative levels inverse to the abundance of Cx29 in myelin and paucity of Cx29 in oligodendrocyte somata. Further, our findings suggest a scaffolding and/or regulatory role of ZO-1 at the oligodendrocyte side of astrocyte-to-oligodendrocyte gap junctions. Keywords connexin47; connexin32; connexin43; gap junctions; PDZ domains; glia Gap junctions are localized at specialized cell-to-cell contacts of plasma membranes in which connexin (Cx) proteins form bidirectional intercellular channels that allow passage of ions and *Corresponding author. Tel: +1-204-789-3767; fax: +1-204-789-3934. E-mail address: nagyji@ms.umanitoba.ca (J. I. Nagy).. 1 Present address: Department of Pathology, Weifang Medical College, PR China. NIH Public Access Author ManuscriptNeuroscience. Author manuscript; available in PMC 2007 March 8. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscriptsmall molecules between cells (Goodenough et al., 1996;Kumar and Gilula, 1996;Willecke et al., 2002). In the CNS, astrocytes are extensively coupled by gap junctions (astrocyte-toastrocyte gap junctions [A/A junctions]) that, base...

There has been disagreement regarding the source of new cells for planarian regeneration. Electron microscopy was used to study this problem in surgically decapitated asexual Dugesia dorotocephala. Comparison of the fine structural morphology of cells found in prophase, metaphase, anaphase, and telophase with those of various cell types in interphase shows that the mitotic cells and resulting daughter cells are all neoblasts. This mitosis, which appears quite classical, was observed in the parenchyma of preexisting tissue but not in the regeneration blastema. This accords with previous observations indicating that blastema cells are already differentiated out of the neoblast stage, and the present observation that mitotic activity appears restricted to neoblasts. However, persistence of neoblast characteristics, e.g., numerous free, or poly-, ribosomes and diminished, but still prominent, nuclear satellite material, indicate recent differentiation of blastema cells from neoblasts. Previous studies have shown a basal mitotic rate in the parenchymal neoblasts of uninjured asexual planarians. This mitotic incidence remains the same for the first day, then increases to a maximum on the second and third days following decapitation. Despite a n exhaustive search involving construction of electronmicrographic montages of all or most of the wound area and adjacent tissue at various times ranging from 1 to 72 hours after decapitation, no evidence of cellular dedifferentiation was observed. Joint consideration of present and previous results indicate that new specialized cells, whether required for normal turnover replacement, asexual reproduction, or reconstitutive regeneration, are all differentiated from parenchymal neoblasts which maintain their numbers by mitotic production of more neoblasts.

Most gap junctions between neurons in mammalian retina contain abundant connexin36, often in association with the scaffolding protein zonula occludens-1. We now investigate co-association of connexin36, zonula occludens-1, zonula occludens-2 and Y-box transcription factor 3 (zonula occludens-1-associated nucleic acid-binding protein) in mouse and rat retina. By immunoblotting, zonula occludens-1-associated nucleic acid-binding protein and zonula occludens-2 were both detected in retina, and zonula occludens-2 in retina was found to co-immunoprecipitate with connexin36. By immunofluorescence, the four proteins appeared as puncta distributed in the plexiform layers. In the inner plexiform layer, most connexin36-puncta were co-localized with zonula occludens-1, and many were co-localized with zonula occludens-1-associated nucleic acid-binding protein. Moreover, zonula occludens-1-associated nucleic acid-binding protein was often co-localized with zonula occludens-1. Nearly all zonula occludens-2-puncta were positive for connexin36, zonula occludens-1 and zonula occludens-1-associated nucleic acid-binding protein. In the outer plexiform layer, connexin36 was also often co-localized with zonula occludens-1-associated nucleic acid-binding protein. In connexin36 knockout mice, labeling of zonula occludens-1 was slightly reduced in the inner plexiform layer, zonula occludens-1-associated nucleic acid-binding protein was decreased in the outer plexiform layer, and both zonula occludens-1-associated nucleic acid-binding protein and zonula occludens-2 were markedly decreased in the inner sublamina of the inner plexiform layer, whereas zonula occludens-1, zonula occludens-2 and zonula occludens-1-associated nucleic acid-binding protein puncta persisted and remained co-localized in the outer sublamina of the inner plexiform layer. By freeze-fracture replica immunogold labeling, connexin36 was found to be co-localized with zonula occludens-2 within individual neuronal gap junctions. In addition, zonula occludens-1-associated nucleic acid-binding protein was abundant in a portion of ultrastructurally-defined gap junctions throughout the inner plexiform layer, and some of these junctions contained both connexin36 and zonula occludens-1-associated nucleic acid-binding protein. These distinct patterns of connexin36 association with zonula occludens-1, zonula occludens-2 and zonula occludens-1-associated nucleic acid-binding protein in different sublaminae of retina, and differential responses of these proteins to connexin36 gene deletion suggest differential regulatory and scaffolding roles of these gap junction accessory proteins. Further, the persistence of a subpopulation of zonula occludens-1/zonula occludens-2/zonula occludens-1-associated nucleic acid-binding protein co-localized puncta in the outer part of the inner plexiform layer of connexin36 knockout mice suggests close association of these proteins with other structures in retina, possibly including gap junctions composed of an as-yet-unidentified connexin.

Free-living flatworms such as planarians are inexpensive to culture, maintain, and use for toxicologic testing in the laboratory. A considerable number of basic studies by ourselves and others indicate that, in simplified miniature, they possess many features of biochemical and physiologic organization similar to higher animals such as mammals. These include a well-developed brain with a varied behavioral repertoire including complex maneuvers of prey capture and learning, with a number of the same neurotransmitters used in mammalian brain. They are sensitive to a variety of the same toxicants. Undifferentiated totipotent stem cells, i.e., "neoblasts," which are capable of mitosis and differentiation into any of the various specialized cell types, permit regeneration of complete planarians from fragments. They also provide new cells to replace those lost in the normal cellular turnover of nonregenerating planarians. Both regeneration of surgical fragments and aberrant remodeling of whole planarians model important features of embyrogenesis and are potentially useful for assaying teratogens. Results are described from studies in which various representative teratogenic toxicants were tested in these two different planarian paradigms. The potential of planarian cephalic regeneration for behavioral teratogenesis investigations is also indicated.

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The small size of the nerve fibers of the planarian nervous system render the details of its neuroanatomy invisible to optical microscopy. Electron microscopic studies on the nervous system of Dugesia dorotocephala are described showing the neuropil of the brain, the origin of the ventral nerve cords from the brain neuropil, synaptic junctions in the neuropil, and "giant" fibers in the longitudinal conduction system. Two major kinds of synapses can be discerned as well as the preand post-synaptic sides of each. There appear to be three major kinds of cells comprising the brain: neurons, neurosecretory cells, and neuroaccessow cells. The neurons are unmyelinated, contain neurotubules, and located neuropil.