A case of successful conservative chemotherapy for intramural pregnancy

OBJECTIVE

To describe a rare case of intramural pregnancy diagnosed with the use of magnetic resonance imaging (MRI) and conservatively managed.

DESIGN

Case report.

SETTING

Department of obstetrics and gynecology in a university hospital.

PATIENT

A 33-year-old healthy patient with a history of a partial mole after 3 years of primary unexplained infertility.

INTERVENTION(S)

Laparoscopic and transvaginal local injections of methotrexate.

MAIN OUTCOME MEASURE(S)

Transvaginal ultrasound (US) and MRI findings.

RESULT

Treatment was successful, with no complications, and the patient's reproductive potential was preserved.

CONCLUSION(S)

Early detection of intramural pregnancy with the use of transvaginal US is important, and MRI is a useful, noninvasive imaging modality. Chemotherapy with methotrexate is an effective treatment that allows preservation of reproductive potential.

Proline-rich antimicrobial peptide, PR-39 gene transduction altered invasive activity and actin structure in human hepatocellular carcinoma cells

PR-39 is an endogenous proline-rich antimicrobial peptide which induces the synthesis of syndecan-1, a transmembrane heparan sulphate proteoglycan involved in cell-to-matrix interactions and wound healing. Previously, we revealed that the expression of syndecan-1 was reduced in human hepatocellular carcinomas with high metastatic potential and speculated that syndecan-1 played an important role in inhibition of invasion and metastasis. It is assumed that a modification of this process with PR-39 and syndecan-1 may result in a new strategy by which it can inhibit the invasion and metastasis. Therefore, we transduced a gene of PR-39 into human hepatocellular carcinoma cell line HLF, which shows a low expression of syndecan-1 and a high in vitro invasive activity, and examined whether this procedure could reduce the invasive activity of tumour cells. In two transfectants with PR-39 gene, the syndecan-1 expression was induced and the invasive activity in type I collagen-coated chamber was inhibited. Moreover, these transfectants showed the suppression of motile activity assayed by phagokinetic tracks in addition to the disorganization of actin filaments observed by a confocal imaging system. In contrast, five transfectants with syndecan-1 gene in the HLF cells revealed suppression of invasive activity but did not alter the motile activity and actin structures of the cell. These results suggest that PR-39 has functions involved in the suppression of motile activity and alteration of actin structure on human hepatocellular carcinoma cells in addition to the suppression of invasive activity which might result from the induction of syndecan-1 expression.

STAT5 as a molecular regulator of proliferation, differentiation and apoptosis in hematopoietic cells

Signal transducers and activators of transcription (STATs) play key roles in growth factor-mediated intracellular signal transduction. In the present study using a constitutively active STAT5 mutant, we show that STAT5 has pleiotropic functions regulating cell proliferation, differentiation and apoptosis in an IL-3-dependent Ba/F3 cell line. The mutant STAT5 possessed constitutive tyrosine phosphorylation and DNA binding activity, induced expression of bcl-xL and pim-1 in the absence of IL-3 in Ba/F3 cells, and rendered Ba/F3 cells factor-independent. Unexpectedly, IL-3 treatment of the factor-independent Ba/F3 cells expressing the constitutively active STAT5 resulted in apoptosis within 24 h, or differentiation followed by cell death. In these cells, mRNA expression of growth inhibitory genes downstream of STAT5 such as CIS, JAB/SOCS-1/SSI-1, and p21(WAF1/Cip1) was highly induced, correlating with prolonged hyper-phosphorylation of the mutant STAT5 after IL-3 stimulation. Of the STAT5-regulated genes, we found that constitutive expression of JAB/SOCS-1/SSI-1 was sufficient to induce apoptosis of Ba/F3 cells, while p21(WAF1/Cip1) could induce differentiation of these cells. In contrast, constitutive expression of pim-1 was sufficient to induce IL-3-independent growth of Ba/F3 cells. These findings suggest that a single transcription factor regulates cell fate by varying the intensity and duration of the expression of a set of target genes.

Expression levels of B cell surface immunoglobulin regulate efficiency of allelic exclusion and size of autoreactive B-1 cell compartment

Surface-expressed immunoglobulin (Ig) has been shown to have a critical role in allelic exclusion of Ig heavy (H) and light (L) chains. Although various degrees of suppression of endogenous Ig expression are observed in Ig transgenic (Tg) mice, it was not clear whether this difference is due to different onsets of Tg expression or to different levels of Tg expression, which are obviously affected by integration sites of the transgene. In this study we generated antierythrocyte antibody Tg mice that carry tandem joined H and L chain transgenes (H+L) and confirmed that homozygosity of the transgene loci enhances the level of transgene expression as compared with heterozygosity. Suppression of endogenous H and L chain gene expression was stronger in homozygous than in heterozygous Tg mice. Similar results were obtained in control Tg mice carrying the H chain only. These results suggest that there is a threshold of the B cell receptor expression level that induces allelic exclusion. In addition, despite the same B cell receptor specificity, the size of Tg autoreactive B-1 cell compartment in the peritoneal cavity is larger in homozygous than in heterozygous mice, although the number of the Tg B-2 cell subset decreased in the spleen and bone marrow of homozygous Tg mice as compared with heterozygous Tg mice. By contrast, homozygosity of the H chain alone Tg line, which does not recognize self-antigens, did not increase the size of the peritoneal B-1 subset. These results suggest that the size of the B-1 cell subset in the Tg mice may depend on strength of signals through B cell receptors triggered by self-antigens.

Induction of germline transcription in the TCRgamma locus by Stat5: implications for accessibility control by the IL-7 receptor

IL-7 receptor (IL-7R) plays critical roles in lymphocyte development by promoting survival and proliferation and by inducing V(D)J recombination in TCR and Ig loci. Here, we demonstrate that IL-7R-activated Stat5 binds to consensus motifs in the 5' regions of Jgamma segments and induces germline transcripts. We also show that a constitutively active form of Stat5 restores V-J recombination of TCRgamma genes and partially rescues T cell development from IL-7R(-/-) T cell precursors, especially in favor of gammadelta T cells. Therefore, this study reveals a potential role of Stat5 in T cell development and also implies that IL-7R may control the accessibility of the TCRgamma locus through Stat5-induced germline transcription.

Effects of photoperiod on salmon GnRH mRNA levels in brain of castrated underyearling precocious male masu salmon

Previous studies have suggested that activation of salmon gonadotropin-releasing hormone (sGnRH)-producing neurons is induced by the combined effects of photoperiod and steroid hormones in underyearling males of the masu salmon, Oncorhynchus masou. The present study further assesses the effects of photoperiod and steroid hormones on sGnRH synthetic activity and examines the changes in sGnRH mRNA levels in the brains of castrated underyearling precocious male masu salmon by manipulating the photoperiod for 60 days from August through October. In castrated males in which plasma testosterone levels decreased to low levels, sGnRH mRNA levels in the preoptic area (POA) increased under a short photoperiod (8L-16D), whereas they remained at low levels under a long photoperiod (16L-8D) for a 2-month duration. In sham-operated males, sGnRH mRNA levels in the ventral telencephalon and those in the POA increased in October with testicular maturation even under a long photoperiod with a delay of 1 month compared with the short photoperiod group. These results suggest that preoptic sGnRH-producing neurons receive short photoperiodic signals and that either short photoperiod or steroid hormone secretion is required for the activation of sGnRH synthesis in underyearling precocious male masu salmon.

Requirement of IL-5 for induction of autoimmune hemolytic anemia in anti-red blood cell autoantibody transgenic mice

IL-5, IL-10 and lipopolysaccharide (LPS) are known to activate B-1 cells in vivo in normal mice and anti-red blood cell autoantibody transgenic mice (HL mice). To assess the exact role of IL-5 in proliferation and activation of peritoneal B-1 cells, we analyzed IL-5 receptor alpha chain-deficient HL (IL-5Ralpha-/- x HL) mice generated by the cross between IL-5Ralpha-/- and HL mice. In IL-5Ralpha-/- x HL mice, Ig-producing B-1 cells in the peritoneal cavity were negligible, although the total number of B-1 cells in the peritoneal cavity were as many as 30% of that in HL mice. Moreover, LPS- or IL-10-induced differentiation of B-1 cells into antibody-producing cells was severely impaired in IL-5Ralpha-/- x HL mice. We also used in vivo 5-bromo-2'-deoxyuridine labeling to estimate the proliferation of B-1 cells in IL-5Ralpha-/- mice. The absence of IL-5Ralpha did not affect spontaneous proliferation of peritoneal B-1 cells. However, induced proliferation of peritoreal B-1 cells by oral administration of LPS was markedly impaired in IL-5Ralpha-/- mice. These results suggest that IL-5 is required for activation-associated proliferation of B-1 cells but not for their spontaneous proliferation and support the idea that IL-5 plays an important role on the induction of autoantibody production from B-1 cells.

Reverse transcriptase (RT)-independent as well as RT-dependent HIV-1 replication exists in syncytia following cell fusion

We studied the role of reverse transcriptase (RT) in human immunodeficiency virus (HIV)-1 replication in syncytia following cell fusion. A chronically HIV-1-infected MOLT-4 (MOLT-4/IIIB) cells allow HIV-1 replication and induce syncytium formation between uninfected MOLT-4 cells. AZT (3'-azido-3'-deoxythymidine, 1 microM) inhibited neither HIV-1 replication in MOLT-4/IIIB cells nor the syncytium formation induced by concultivation of MOLT-4/IIIB cells with uninfected MOLT-4 cells. In the supernatant of the syncytium containing culture a remarkably higher titer of p24 antigen was produced than in that of MOLT/IIIB cell culture. AZT inhibited p24 antigen production by HIV-1 in the syncytia to levels to comparable to that in MOLT-4/IIIB cells which were treated with AZT. In addition, p24 production by HIV-1 in the syncytia formed by cocultivation of CL-2 cells, which are chronically infected with HIV-1 but lack functional RT, with uninfected MOLT-4 cells was not different from that in CL-2 cells alone. The results suggest that HIV-1 RT plays an important role in HIV-1 replication within the syncytia but an RT-independent replication process which is essential for syncytium formation also exists in the syncytia. These results indicate that not only RT inhibitors but also inhibitors of syncytium formation are essential for anti-HIV therapy.

Mercury and other trace metals (Ag, Cr, Co, and Ni) in soft tissue and byssus of Mytilus edulis from the east coast of Kyushu Island, Japan

Concentrations of Hg and other metals such as Ag, Cr, Co and Ni in soft tissues and byssi of the blue mussel (Mytilus edulis) from three sites along the east coast of Kyushu Island, Japan, were determined by a cold-vapor technique. Large inter-regional differences in metal concentrations in both soft tissues and byssi were observed. The tissue concentrations of Hg were significantly greater in M. edulis from the most contaminated locations (Saganoseki) compared to those from a non-industrialized area (Urashiro). It is evident that, compared to the soft tissue, byssus is a more sensitive biomonitor for Hg, Cr, Co and Ni. From the data obtained in the present study evidently results that the soft tissue and especially byssi of M. edulis appear to be good bioindicators for identification of coastal areas exposed to Hg contaminants.

The cellular kinase binding motifs (PxxP and RR) in human immunodeficiency virus type 1 Nef protein are dispensable for producer-cell-dependent enhancement of viral entry

We have recently demonstrated that human immunodeficiency virus type 1 (HIV-1) Nef is required for enhancing viral infectivity by increasing the efficiency of viral entry in a producer-cell-dependent manner, suggesting the possible involvement of a cellular factor(s) in the enhancement of viral entry. Moreover, it has been reported that a proline-rich (PxxP) motif and an Arg-Arg (RR) motif in HIV-1 Nef bind to the SH3 domain of the Src-family tyrosine kinase Hck and to a serine/threonine kinase, respectively. To address whether these cellular kinase binding motifs, PxxP and RR, could be involved in virus producer-cell-dependent enhancement of viral entry, we constructed two nef mutant proviral clones in which these motifs were mutated. The results show that the HIV-1 Nef PxxP motif, which significantly influenced viral infectivity, and the RR motif, which modestly affected viral infectivity, were both dispensable for enhanced viral entry, thus suggesting that another interaction of Nef with a cellular factor(s) is involved in the efficiency of viral entry.

Alymphoplasia is caused by a point mutation in the mouse gene encoding Nf-kappa b-inducing kinase

The alymphoplasia (aly) mutation of mouse is autosomal recessive and characterized by the systemic absence of lymph nodes (LN) and Peyer's patches (PP) and disorganized splenic and thymic structures with immunodeficiency. Although recent reports have shown that the interaction between lymphotoxin (LT) and the LT beta-receptor (Ltbeta r, encoded by Ltbr) provides a critical signal for LN genesis in mice, the aly locus on chromosome 11 is distinct from those for LT and its receptor. We found that the aly allele carries a point mutation causing an amino acid substitution in the carboxy-terminal interaction domain of Nf-kappa b-inducing kinase (Nik, encoded by the gene Nik). Transgenic complementation with wild-type Nik restored the normal structures of LN, PP, spleen and thymus, and the normal immune response in aly/aly mice. In addition, the aly mutation in a kinase domain-truncated Nik abolished its dominant-negative effect on Nf-kappa b activation induced by an excess of Ltbeta r. Our observations agree with previous reports that Ltbeta r-deficient mice showed defects in LN genesis and that Nik is a common mediator of Nf-kappa b activation by the tumour necrosis factor (TNF) receptor family. Nik is able to interact with members of the TRAF family (Traf1, 2, 3, 5 and 6), suggesting it acts downstream of TRAF-associating receptor signalling pathways, including Tnfr, Cd40, Cd30 and Ltbeta r. The phenotypes of aly/aly mice are more severe than those of Ltbr-/- mice, however, indicating involvement of Nik in signal transduction mediated by other receptors.

IL-7 receptor alpha+ CD3(-) cells in the embryonic intestine induces the organizing center of Peyer's patches

Peyer's patch (PP) organogenesis proceeds through three histologically distinct steps: formation of organizing centers expressing VCAM-1 and ICAM-1 in segregated regions of the intestine at 15.5 days post-coitus (d.p.c.) (step I), accumulation of blood cells expressing different sets of surface markers to this region at 16.5-17.0 d.p.c. (step II), and entry of CD3+ and B220+ lymphocytes just before birth (step III). PP formation of both Il7ra-/- and Lta-/- mice is impaired from step I, suggesting involvement of the two molecules at the same timing in PP organogenesis. Expression of lymphotoxin (LT) alpha and LTbeta in IL-7 receptor (IL-7R) alpha+ cells in the intestine indicates that defects of Il7ra-/- and Lta-/- mice are due to functional inability of IL-7Ralpha+ cells in the induction of PP anlage. Blocking of IL-7Ralpha function by a single injection of the antagonistic mAb in 15.5 d.p.c. embryos suppressed appearance of VCAM-1(+) spots and expression of LTalpha and LTbeta in the intestine, which eventually resulted in mice without PP but are otherwise normal. Intestinal IL-7Ralpha+ cells are lymphoid in morphology but CD3(-) and functional in both nu/nu and Rag2-/- mice. These results implicate IL-7Ralpha+ CD3(-) cells as the direct inducer of the organizing center of PP.

Increase of serum des-gamma-carboxy prothrombin in alcoholic liver disease without hepatocellular carcinoma

The purpose of this study is to determine serum des-gamma-carboxy prothrombin (DCP) levels in benign liver diseases by a new sensitive method, and to demonstrate the elevation of serum DCP in alcoholic liver disease (ALD) without hepatocellular carcinoma (HCC). Median values of serum DCP were 16.2 mAU/ml (range: 3.2 to 1570 mAU/ml) in ALD and 16.7 mAU/ml (1.2 to 75.4 mAU/ml) in viral liver disease (VLD). Using the cut-off value of 40 mAU/ml as a tumor marker for HCC, 21% (11/52) was positive in ALD and 2% (1/57) was positive in VLD (p = 0.0014, Fisher's exact probability test), and 27% (9/33) was positive in alcoholic liver cirrhosis and 3% (1/39) was positive in viral liver cirrhosis (p = 0.0042, Fisher's exact probability test). The positive rate of DCP was significantly (p < 0.001, Spearman's rank correlation test) correlated with the severity of liver disease in ALD. Serum vitamin K level was not decreased in cases with ALD. In a demonstrable case, serum DCP was decreased after abstinence and was increased again after the beginning of ethanol intake, suggesting the involvement of ethanol to the elevation of serum DCP in ALD. In conclusion, serum DCP was significantly elevated in ALD, compared with VLD, although the mechanism of the elevation of DCP was not clarified. Ethanol intake may act, in part, on the increase of serum DCP in ALD.

Establishment of persistent infection with HIV-1 abrogates the caspase-3-dependent apoptotic signaling pathway in U937 cells

Treatment of 26L cells, a subclone obtained from U937 cells, with TNF-alpha or DNA-damaging agents such as teniposide (VM26) and camptothecin (CPT) induced morphologically and biochemically typical apoptotic changes, including the activation of procaspase-3. The cells persistently infected with HIV-1 (26L/HIV), however, showed a marked resistance to VM26 and CPT, whereas they hardly lost the sensitivity to TNF-alpha. TNF-alpha-induced apoptosis of 26L/HIV cells proceeded without the increase in caspase-3 activity, indicating that signaling for apoptosis in the infected cells proceeded through an alternative caspase-3-independent pathway which could respond to TNF-alpha but not to VM26 and CPT. The evidence that p-toluenesulfonyl-l-lysine chloromethyl ketone (a trypsin-like serine protease inhibitor) blocked VM26- and CPT-induced apoptotic changes but not TNF-alpha-induced apoptosis also supported the existence of the alternative TNF-alpha-inducible pathway. The results also suggest that a TLCK-sensitive protease is involved upstream of the procaspase-3 activation process and that the protease is essential for the progress of VM26- and CPT-induced apoptosis. The similar effect of HIV-1-productive infection on the apoptosis induced by the DNA-damaging agents was also confirmed by utilizing U1 cells, which are latently HIV-1-infected U937 cells. The cells became resistant to these agents after induction of the viral production by pretreatment with PMA. These results suggest that persistent HIV-1 infection blocks an apoptotic pathway triggered by DNA damaging agents through the inhibition of the procaspase-3 activation process.

Antigen-driven clonal accumulation of peritoneal gammadelta T cells in vivo

How the clonality of gammadelta T cells changes in response to exogenous antigens is uncertain. Here we analyzed kinetics of Vgamma1.1 and Vgamma2 T cell clonality after intraperitoneal injection of purified protein derivatives (PPD) by the heterogeneity of the third complementarity determining region (CDR3) length in Vgamma1.1-Jgamma4-Cgamma4 and Vgamma2-Jgamma1-Cgamma1 junctions. The V-J junctions were analyzed in intrahepatic lymphocytes (IHL), spleen cells, and peritoneal exudate cells (PEC) by polyacrylamide gel electrophoresis. Gammadelta T cells expressing Vgamma1.1 and Vgamma2 genes were heterogeneous in normal mice. Accumulation of specific Vgamma1.1 T cell clones was transiently detected 7 days after the injection in PEC, but no accumulation was observed in IHL and spleen cells. The accumulated clones disappeared by 4 weeks. Transient accumulation of Vgamma2 T cell clones was also observed in PEC at the early phase after the injection. These results suggest that gammadelta T cells with specific TCR respond to PPD and temporary accumulate in the peritoneal cavity, but not in liver and spleen.

High susceptibility of Mongolian gerbil (Meriones unguiculatus) to Borna disease virus

Borna disease virus (BDV) is a neurotropic enveloped virus with a nonsegmented, single-, negative-stranded RNA genome. This virus induced encephalitis in experimentally infected adult rats, but in newborn rats BDV established a persistent, tolerant infection with no apparent clinical signs. Here, we report evidence that newborn Mongolian gerbils (Meriones unguiculatus) are more susceptible to experimental intracranial inoculation of horse-derived BDV in persistently infected MDCK cells, compared with similar inoculation in newborn rats. All inoculated newborn gerbils, but not rats, died 30 days after infection. Reverse transcriptase-polymerase chain reaction amplified BDV-specific sequences in several regions including the brain. Histopathological analysis revealed apparent inflammatory reactions in the brains of inoculated gerbils but not rats, although similar levels of BDV RNA were detected in both gerbil and rat brains. BDV-specific antigen and RNA were identified predominantly in neurons in the brains by immunohistochemistry with antibodies to BDV and in situ hybridization with BDV-specific riboprobes, respectively. BDV in the gerbil brain was easily rescued by co-cultivation of the brain homogenate with human oligodendroglioma cells. Thus, gerbils seem to be a useful animal model for studying BDV-induced pathogenesis in the brain.

The YXXL sequences of a transmembrane protein of bovine leukemia virus are required for viral entry and incorporation of viral envelope protein into virions

The cytoplasmic domain of an envelope transmembrane glycoprotein (gp30) of bovine leukemia virus (BLV) has two overlapping copies of the (YXXL)2 motif. The N-terminal motif has been implicated in in vitro signal transduction pathways from the external to the intracellular compartment and is also involved in infection and maintenance of high viral loads in sheep that have been experimentally infected with BLV. To determine the role of YXXL sequences in the replication of BLV in vitro, we changed the tyrosine or leucine residues of the N-terminal motif in an infectious molecular clone of BLV, pBLV-IF, to alanine to produce mutated proviruses designated Y487A, L490A, Y498A, L501A, and Y487/498A. Transient transfection of African green monkey kidney COS-1 cells with proviral DNAs that encoded wild-type and mutant sequences revealed that all of the mutated proviral DNAs synthesized mature envelope proteins and released virus particles into the growth medium. However, serial passages of fetal lamb kidney (FLK) cells, which are sensitive to infection with BLV, after transient transfection revealed that mutation of a second tyrosine residue in the N-terminal motif completely prevented the propagation of the virus. Similarly, Y498A and Y487/498A mutant BLV that was produced by the stably transfected COS-1 cells exhibited significantly reduced levels of cell-free virion-mediated transmission. Analysis of the protein compositions of mutant viruses demonstrated that lower levels of envelope protein were incorporated by two of the mutant virions than by wild-type and other mutant virions. Furthermore, a mutation of a second tyrosine residue decreased the specific binding of BLV particles to FLK cells and the capacity for viral penetration. Our data indicate that the YXXL sequences play critical roles in both viral entry and the incorporation of viral envelope protein into the virion during the life cycle of BLV.

Fine structure and morphogenesis of Borna disease virus

Borna disease virus (BDV), a negative nonsegmented single-stranded RNA virus, has not been fully characterized morphologically. Here we present what is to our knowledge the first data on the fine ultrastructure and morphogenesis of BDV. The supernatant of MDCK cells persistently infected with BDV treated with n-butyrate contained many virus-like particles and more BDV-specific RNA than that of untreated samples. The particles were spherical, enveloped, and approximately 130 nm in diameter; had spikes 7 nm in length; and reacted with BDV p40 antibody. A thin nucleocapsid, 4 nm in width, was present peripherally in contrast to the thick nucleocapsid of hemagglutinating virus of Japan. The BDV particles reproduced by budding on the cell surface.

Two proline-rich nuclear localization signals in the amino- and carboxyl-terminal regions of the Borna disease virus phosphoprotein

Borna disease virus (BDV) uses a unique strategy of replication and transcription which takes place in the nucleus, unlike other known, nonsegmented, negative-stranded RNA viruses of animal origin. In this process, viral constituents necessary for replication must be transported to the nucleus from the cytoplasm. We report here the evidence that BDV P protein, which may play an important role in viral replication and transcription, is transported into the nucleus in the absence of other viral constituents. This transportation is accomplished by its own nuclear localization signals (NLSs), which are present in both N-terminal (29PRPRKIPR36) and C-terminal (181PPRIYPQLPSAPT193) regions of the protein. These two NLSs can function independently and both have several Pro residues as key amino acids.

Development of peptide vaccines inducing production of neutralizing antibodies against HIV-1 viruses in HLA-DQ6 mice

Peptide vaccines against HIV-1 were prepared according to the cassette theory that we had proposed previously. An amino acid sequence of B subtype consensus of the HIV-1 V3 region was introduced into the MHC binding component with a supermotif for various MHC class II. The peptide vaccines induced T-cell responses in the DQ6 mice in which only DQ6 molecules were expressed as MHC class II. By contrast, an original V3 peptide including the consensus sequence was non-immunogenic in the DQ6 mice. Antibodies obtained from the DQ6 mice immunized with the peptide vaccines neutralized laboratory B subtype strains of HIV-1 in vitro. It may be anticipated that these peptide vaccines protect infection of HIV-1 in DQ6 positive individuals.

Enhancement of human immunodeficiency virus type 1 infectivity by Nef is producer cell-dependent

The growth kinetics of wild-type and nef mutant viruses of human immunodeficiency virus type 1 were comparatively analysed in several human CD4+ cell lines. Delayed replication of nef mutant virus was observed in all cell lines examined. To determine the stage in the virus replication cycle that is affected by Nef, a single-round replication assay was performed. Initially, the expression of marker genes in transfected cells was examined in order to study the role of Nef in the late phase of infection. The results obtained indicated that Nef is dispensable during the transcription to virion production stage. Next, the effect of Nef on the early phase was investigated with a single-round infection. It was demonstrated that Nef is required in the early phase of the virus replication cycle, from virion adsorption to integration. Finally, the infectivity of virus stocks prepared from four cell lines was determined. The relative infectivity of the nef mutant from the four cell lines differed. Taken together, we conclude that Nef acts via modulation of viral particles to enhance virus infectivity in a cell-dependent manner.

Producer cell-dependent requirement of the Nef protein for efficient entry of HIV-1 into cells

A proviral nef gene mutant of human immunodeficiency virus type 1 (HIV-1) was evaluated for its defective early replication step. Virus stocks were prepared from six CD4-positive and -negative cell lines transfected with wild-type (wt) or the nef mutant clone and inoculated into two target CD4-positive cell lines to monitor the efficiency of viral entry process. The nef mutant virions produced in one cell line exhibited a severe defect in the entry process, although those produced in the other five cell lines were only slightly less efficient than the wt virions at entering into cells. These results have demonstrated that the HIV-1 Nef is critical for efficient viral entry in a producer cell-dependent manner.

Ontogenic development of salmon GnRH and chicken GnRH-II systems in the brain of masu salmon (Oncorhynchus masou)

Ontogenic development of salmon gonadotropin-releasing hormone (GnRH) and chicken GnRH-II systems in masu salmon (Oncorhynchus masou) was examined. Salmon GnRH was first detected by radioimmunoassay in the embryo on day 36 after fertilization. Salmon GnRH-immunoreactive fibers were detected initially by immunocytochemistry in the vicinity of the olfactory placode of the embryo (day 36) and were distributed widely in the brain as well as in the pituitary gland of fish just after hatching (day 80). Salmon GnRH-immunoreactive neuronal somata were first detected about 6 months after fertilization in the rostroventral brain area, ranging from the olfactory nerve to the preoptic area. Salmon GnRH neuronal somata were detected earlier by in situ hybridization than by immunocytochemistry. Neuronal somata expressing salmon GnRH mRNA were first detected in the vicinity of the olfactory epithelium on day 40 and then were seen to be migrating from the olfactory epithelium, along the olfactory nerve, on day 60 and in the transitional area between olfactory nerve and olfactory bulb on day 80. In the brain, these neurons were first detected in the ventral olfactory bulb on day 80, and thereafter they were also detected in the caudal brain regions. The chicken GnRH-II system was detected later than the salmon GnRH system; chicken GnRH-II was first detected by radioimmunoassay on day 57, and chicken GnRH-II-immunoreactive fibers were first detected on day 67. Chicken GnRH-II-immunoreactive neuronal somata were not detected during the observation period. These results suggest that salmon GnRH neurons derive from the olfactory placode and then migrate into the brain and that salmon GnRH is synthesized before chicken GnRH-II.

Advanced endocrine cell carcinoma of the gallbladder: a patient with 12-year survival

Gallbladder carcinoid is a rare disease. In previous reports, classical carcinoid, an entity with a good prognosis, has not been distinguished from endocrine cell carcinoma, a tumor associated with marked cell atypia and mitosis, and a poor prognosis. The patient was a 66 year old woman who presented to our hospital with a chief complaint of jaundice. Pre-operatively, she was diagnosed as having advanced gallbladder carcinoma invading the liver and the hepatic hilus. The patient underwent right hepatic trisegmentectomy with en bloc resection of the caudate lobe and extrahepatic bile ducts, extended lymph node clearance and left hepaticojejunostomy. Histopathological examination showed positive Grimelius staining, marked mitosis, and intense atypism, hence, the tumor was diagnosed as an endocrine cell carcinoma. Twelve years after surgery, the patient is healthy, without any sign of recurrence. We present this novel case of long-term survival and review the literature.

Unrelated umbilical cord-blood stem cell transplantation: a report from Kanagawa Cord Blood Bank, Japan

Umbilical cord-blood (CB) has been used as a source of hematopoietic stem cells in pediatric patients with sibling donors. As a result of the success with CB transplantation from sibling donors, pilot programs for the banking of unrelated donor CB were initiated in the organization of Kanagawa Cord Blood Bank, Japan in 1995. As of December 1997, unrelated donor CB was used to reconstitute hematopoiesis in seven patients aged 0.7-12.8 years, weighing 7-36 kg with high-risk leukemia (n = 5), myelodysplastic syndrome (n = 1), and immunodeficiency syndrome (n = 1). Engraftment of CB was achieved in six patients. The absolute neutrophil count reached 500/microliter in a median of 27 days; a platelet count of 20,000/microliter was reached by a median of 64 days in three patients who could be evaluated. Five patients are currently surviving. Grade I GVHD developed in three patients and grade III in one patient; no GVHD developed in three patients. Although only a small number of patients have been studied and the period of observation is too short to determine long-term survival, HLA-matched or HLA-mismatched CB from unrelated donors can provide an alternative source of hematopoietic reconstitution for clinical transplantation.

A specific T-cell subset with CD4+/CD38- markers derived from HIV-1 carriers induces apoptosis in healthy donor-derived T-lymphocytes

Apoptosis is an important mechanism of human immunodeficiency virus type 1 (HIV-1)-induced T-cell depletion. Our recent findings revealed mitogenic stimulation-dependent apoptosis induction in healthy donor-derived peripheral blood T-lymphocytes after adsorption with defective HIV-1 particles through acquirement by a subset of CD4+/CD38- cells of specific killer function. Based on these in vitro observations, we have extended the significance of this killing activity of CD4+/CD38- cells directly derived from HIV-1 carriers. The CD4+/CD38- cells from HIV-1-positive individuals showed significantly higher cell-killing activities than those from HIV-1-negative donors by co-culture with allogeneic resting T-cells after mitogenic stimulation. Furthermore, most of the samples induced apoptosis in a Fas-dependent manner. Thus, it is suggested that HIV-1 infection-related apoptosis is triggered by inappropriate activation of a certain resting T-cell subset, presumably due to adsorption with HIV-1 particles.

Loss of heterozygosity of NF1 gene in juvenile chronic myelogenous leukemia with neurofibromatosis type 1

To investigate a genetic relation between juvenile chronic myelogenous leukemia (JCML) and neurofibromatosis type 1 (NF-1), we analyzed the NF1 gene in the leukemic cells of a JCML patient with NF-1. We found a point mutation in exon 29 of one allele and a deletion of the other normal allele in the leukemic cells. The point mutation is considered a germline mutation because it was also detected in fibroblasts obtained from the bone marrow of the patient and the peripheral blood mononuclear cells from a sibling. A loss of heterozygosity of NF1 gene may contribute to the progression of leukemia in NF-1 patients.

Dependence on host cell cycle for activation of human immunodeficiency virus type 1 gene expression from latency

Human immunodeficiency virus type 1 (HIV-1) establishes latent infection of a certain population of CD4+ host cells which could be long-term reservoirs for HIV-1. The expression of viral genes in such long-term infected cells is strongly regulated by cellular status, such as the phase of the cell cycle or stage of cell differentiation. Here, viral gene expression in synchronized U1 cells, a monocytic cell clone latently infected with HIV-1, was characterized. The expression of HIV-1 antigens was detected exclusively at G2/M phase in U1 cells, irrespective of phorbol myristate acetate (PMA) treatment. The induction of HIV-1 gene expression in PMA-treated cells was due to the recruitment of NF-kappaB with DNA-binding activity at G2/M phase. Activated NF-kappaB was induced only by PMA treatment during the late G1 to S, but not after entering G2 phase, indicating that the transcriptional factor(s) involved in viral gene expression is also largely regulated by the host cell cycle. In contrast, the enhancement of antigen expression by treatment with tumour necrosis factor-alpha (TNF-alpha) was cell cycle-independent. In fact, NF-kappaB was activated 2 h after TNF-alpha treatment at all stages of the cell cycle. Thus, the mechanisms of HIV-1 activation from latency in U1 cells by PMA and TNF-alpha treatment are different. The model system using U1 cells shown here may provide insight into the mechanisms responsible for HIV-1 gene expression from latency.

Reduced expression and rare genomic alteration of nm23-H1 in human hepatocellular carcinoma and hepatoma cell lines

We investigated the expression and genomic alteration of nm23-H1 (which encodes a nucleoside diphosphate, kinase A) in 12 human hepatocellular carcinomas (HCCs) and four hepatoma cell lines. The expression of nm23-H1 protein was significantly reduced in HCCs with intrahepatic metastasis (72%) compared with expression in HCCs without intrahepatic metastasis (38%). However, in two of three HCCs examined that had marked reduction of nm23-H1 protein, the nm23-H1 mRNA level was not reduced. A hepatoma cell line, HLF (phenotype, poorly differentiated carcinoma) revealed marked reduction of nm23-H1 protein compared with two other hepatoma cell lines, HuH-1 and HuH-2, although the mRNA level was similar in the three cell lines. No allelic deletion of the nm23-H1 gene was detected in the 12 HCCs examined. No point mutation in the coding region of the nm23-H1 gene was observed in any of the 12 HCCs or the four hepatoma cell lines. These findings suggest that: (i) the expression of nm23-H1 protein is inversely associated with high metastatic potential of HCC, (ii) regulation of nm23-H1 expression may occasionally occur at both the transcriptional and post-transcriptional levels in HCC; and (iii) genomic alteration of nm23-H1 is a rare event in HCC.

Impaired anaphylactic responses with intact sensitivity to endotoxin in mice lacking a platelet-activating factor receptor

Platelet-activating factor (PAF) is a potent phospholipid mediator with diverse biological activities in addition to its well-known ability to stimulate platelet aggregation. Pharmacologic studies had suggested a role for PAF in pregnancy, neuronal cell migration, anaphylaxis, and endotoxic shock. Here we show that disruption of the PAF receptor gene in mice caused a marked reduction in systemic anaphylactic symptoms. Unexpectedly, however, the PAF receptor-deficient mice developed normally, were fertile, and remained sensitive to bacterial endotoxin. These mutant mice clearly show that PAF plays a dominant role in eliciting anaphylaxis, but that it is not essential for reproduction, brain development, or endotoxic shock.

Transmission and propagation in cell culture of virus produced by cells transfected with an infectious molecular clone of bovine leukemia virus

A full-length molecular clone of bovine leukemia virus (BLV) pBLV-IF with two copies of a long terminal repeat (LTR) was constructed from a previously isolated, covalently closed, circular DNA clone, pB6490, that has one copy of the LTR and the pX region split at an EcoRI site. This molecular clone directed the synthesis of viral proteins and the induction of syncytia in transiently transfected cells. In addition, virus particles were released into the culture medium. Serial passages of transient transfectants also resulted in propagation of BLV. After transfection of five cell lines with linearized pBLV-IF and a neomycin-resistance gene, BLV-producing transfectants were established in cell lines COS-1 and 23CLN that did not form syncytia upon expression of BLV. In HeLa and FLK cells, BLV produced by a stable COS-1 transfectant was transmitted by both cell-free and cell-to-cell infection. Thus, pBLV-IF encoded an infectious provirus that successfully induced primary and secondary infections. This study indicates that the infectious molecular clone and the virus-producing transfectants could be useful for further examination of the biological properties of BLV.

Two differing salmon GnRH precursor mRNAs are co-expressed in the brain of sockeye salmon

The localization of two salmon-type gonadotropin-releasing hormone (sGnRH) precursors, pro-sGnRH-I (short type) and pro-sGnRH-II (long type), was investigated by using in situ hybridization techniques in the brain of the landlocked sockeye salmon, Oncorhynchus nerka. We used 30-mer oligonucleotide probes complementary to pro-sGnRH-I and pro-sGnRH-II cDNA. No significant differences were observed in the localization of sGnRH neurons expressing pro-sGnRH-I and pro-sGnRH-II mRNAs; both were expressed in the olfactory nerve, the olfactory bulbs, the regions between the olfactory bulb and telencephalon, the ventral telencephalon, the preoptic area, and the hypothalamus. Almost all sGnRH neurons examined co-expressed both precursors. The expression of two sGnRH precursors in the same neuron and the wide distribution of such neurons in the brain suggest that there are no functional differences between the two precursors.

Immunohistochemical detection of 4-hydroxy-2-nonenal-modified-protein adducts in human alcoholic liver diseases

4-Hydroxy-2-nonenal (HNE) is one of the major components of lipid peroxidation product and has been shown to react with proteins to form HNE-protein adducts. HNE-protein adducts are relatively stable and can be used as a marker of radical-mediated cellular damage. We report herein the immunohistochemical analysis of HNE-protein adducts in human alcoholic liver diseases using a specific monoclonal antibody HNEJ-2. Cytoplasm of hepatocytes and bile duct epithelia was positively stained for HNE-protein adducts, and the nucleus was negligibly stained. The immunohistochemical intensity of hepatocytes was classified into three groups: strong, moderate, and faint staining. Strong staining was found in 43% of alcoholic liver diseases and in 4% of viral liver diseases. Hepatocytes of alcoholic liver diseases contained a higher amount of HNE-protein adducts than those of viral liver diseases, and the difference was statistically significant (p = 0.005; chi2 test). Semiquantitative analysis of the histological intensities of HNE-protein adducts and iron indicated a significant positive correlation (p = 0.084; Spearman's rank correlation). The localization of HNE-protein adducts and iron in hepatocytes appeared to be identical. These data suggested the correlation between HNE-protein adducts and iron. Our results indicate that HNE-protein adducts, a marker of oxidative stress-induced damage, are increased in human alcoholic liver damage, and that hepatic siderosis may act on the production of free radicals.

The life-cycle of human immunodeficiency virus type 1

The life-cycle of human immunodeficiency virus type 1 (HIV-1) has been studied using several techniques including immunoelectron microscopy and cryomicroscopy. The HIV-1 particle consists of an envelope, a core and the region between the core and the envelope (matrix). Virus particles in the extracellular space are observed as having various profiles: a central or an eccentric round electron-dense core, a bar-shaped electron-dense core, and immature doughnut-shaped particle. HIV-1 particles in the hydrated state were observed by high-resolution electron cryomicroscopy to be spherical and the lipid membrane was clearly resolved as a bilayer. Projections around the circumference were seen to be knob-like. The shapes and sizes of the projections, especially the head parts, were found to vary with each projection. HIV-1 cores were isolated with a mixture of Nonidet P40 and glutaraldehyde, and were confirmed to consist of HIV-1 Gag p24 protein by immunogold labelling. On infection, the HIV-1 virus was found to enter the cell in two ways: membrane fusion and endocytosis. After viral entry, no structures resembling virus particles could be seen in the cytoplasm. In the infected cells, positive reactions by immunolabelling suggest that HIV-1 Gag is produced in membrane-bound structures and transported to the cell surface by the cytoskeletons. A crescent electron-dense layer is then formed underneath the cell membrane. Finally, the virus particle is released from the cell surface and found extracellularly to be a complete virus particle with an electron-dense core. However, several cell clones producing defective mature, doughnut-shaped (immature) or teardrop-shaped particles were found to be produced in the extracellular space. In the doughnut-shaped particles, Gag p17 and p24 proteins exist facing each other against an inner electron-dense ring, suggesting that the inner ring consists of a precursor Gag protein showing a defect at the viral proteinase.

A novel mutation found in an adrenoleukodystrophy patient who underwent bone marrow transplantation

We identified a novel mutation, L322P, in a patient with X-linked adrenoleukodystrophy (ALD) who underwent bone marrow transplantation (BMT). An identification of the ALD gene mutation enabled us to employ an approach not dependent on the use of radioisotopes for detecting mixed chimerism. This assay could show more than 99.0% of the patient's peripheral white blood cells were replaced by the donor's cells.

Nuclear targeting activity associated with the amino terminal region of the Borna disease virus nucleoprotein

The Borna disease virus (BDV) replicates in the nucleus. The viral p40 protein (N), which is found abundantly in the nucleus in BDV-infected cells, may play an important role in virus replication. To analyze the amino acid residues involved in the nuclear targeting of BDV N, a series of eukaryotic expression plasmids encoding deletion mutants of N was constructed and transfected into COS-7 cells. In indirect immunofluorescence assays with a rabbit anti-BDV N antiserum, wild-type N was located in the nucleus of transfected cells in the absence of other viral constituents. In contrast, mutants lacking the 13 NH2-terminal amino acid residues 1MPPKRRLVDDADA13 in common gave a cytoplasmic localization pattern. Similarly, a mutant with substitution of 4KRR6 by 4NSG6 was retained in the cytoplasm. Furthermore, a nonapeptide, 3PKRRLVDDA11, derived from the NH2-terminal region of N conferred nuclear targeting activity to beta-galactosidase, which normally resides in the cytoplasm. Thus, we have identified the nuclear targeting signal of the BDV N and narrowed it to the NH2-terminal region where 4KRR6 basic amino acid residues are located.

Generation of endogenous tumour necrosis factor-alpha in MOLT-4 cells during the acute replication phase of human immunodeficiency virus type 1 determines the subsequent latent infection

We have characterized the mechanism for human immunodeficiency virus type 1 (HIV-1) latent infection in a human T cell line MOLT-4 subclone no. 8 (MOLT-#8). The inocula used were HIV-1 recovered from MT-4 during the acute (NL-A) and persistent (NL-P) phases after HIV-1 infection. On infection of MOLT-#8 with NL-A, viral antigens first appeared in almost 100% of the cells whereafter the numbers of viable antigen-positive cells declined. In contrast, following infection with NL-P the expression of viral antigens was maintained in almost 100% of the cells. In fact, limiting dilution of NL-P-infected cells allowed us to isolate 43 subclones, all of which were positive for viral antigen expression in almost 100% of the cells (type I). In sharp contrast, only two of 41 subclones from NL-A-infected cells were of type I. Seven subclones were latently infected with HIV-1; latent HIV-1 in six subclones (type II), but not in one type III subclone, was activated by tumour necrosis factor (TNF)-alpha or phorbol 12-myristate 13-acetate. The remaining subclones were negative for the viral genome. Of particular note is the effect of endogenous TNF-alpha generated during the acute phase of virus replication which shifted the virus phenotype. Thus, the presence of TNF-alpha during the acute phase of virus replication seems to play a key role in the selective destruction of cells expressing higher levels of viral antigens and in subsequent establishment of latent infection in host T cells.

[Cord blood stem cell transplantation and cord blood bank]

Human cord blood provides a rich source of hematopoietic stem cells. On the basis of the finding, umbilical cord blood has been postulated to be an alternative and efficacious source of hematopoietic stem cells for allogeneic reconstitution. Early results of cord blood stem cell transplantation (CBSCT) show that the incidence and severity of graft versus host disease has been low in HLA mismatched transplants. Cord blood banking has several advantages such as lack of donor risk, indefinite storage, speed of donor search, viral safety. More than four hundred cases of unrelated CBSCT have been performed in the world. Kanagawa cord blood bank has been established on 1995 and other some private cord blood banks have been established in Japan. Eleven cases of unrelated CBSCT have been reported in Japan. Large scaled public cord blood bank should be established in near future.

Essential role of IL-7 receptor alpha in the formation of Peyer's patch anlage

We investigated the role of IL-7 receptor alpha (IL-7Ralpha) signal in the formation of Peyer's patch (PP) anlage. Although pan-lymphopenia is a common phenotype of rag2-/- and il7ralpha-/- mice, a close inspection revealed nodules corresponding to PP in the adult rag2-/- but not in the il7ralpha-/- mouse. In our previous study, three histologically distinct steps in the formation of PP were identified. The first is the appearance of VCAM-1 + spots in the intestine, which probably represents an initial stage of the formation of the PP anlage. Accumulation of cells bearing IL-7Ralpha, CD4 or Ia in this region then follows and eventually entry of mature lymphocytes expressing CD3 or B220 occurs just before birth. Based on this criterion, we next investigated which of these events is defective in mice with severe combined immunodeficiency. Formation of VCAM-1 + spots and cluster formation of IL-7Ralpha+ cells proceed normally in the rag2-/- mouse which completely lacks mature lymphocytes. In contrast, no VCAM-1+ spots were detected in the embryonic nor neonatal il7ralpha-/- mice, suggesting that IL-7Ralpha signal is involved in the early phase of PP anlage formation. The same defect was found in the jak3-/- mouse. In addition to the appearance of VCAM1+ spots, the clustering of IL-7Ralpha+ cells was absent in the jak3-/- mouse, though IL-7Ralpha+ cells are found to scatter over the intestine. These results indicate that IL-7Ralpha is an essential signal for an early step of PP anlage formation, without which the subsequent processes cannot be initiated.

[Superoxide generation and human cytomegalovirus infection]

Reactive oxygen intermediates (ROI) such as superoxide (O2-), hydrogen peroxide (H2O2) and hydroxyl radicals (.OH) are involved in the pathogenicity of various diseases. There is also evidence that superoxide is involved in disease progression following infection by influenza virus, HIV-1 and human cytomegalovirus (HCMV). Healthy donor-derived peripheral blood monocytes/macrophages, which seem to be the major reservoir for HCMV in vivo, showed significantly higher generation of O2- after HCMV infection. The importance of O2- in cytomegalovirus pneumonitis was also supported in a mouse model system using mouse cytomegalovirus. In addition, the importance of HCMV-induced ROI was also shown in the restenosis and atherosclerosis of smooth muscle cells. This review highlights the relationship between HCMV infection and ROI.

Role of cytosolic phospholipase A2 in allergic response and parturition

Phospholipase A2 (PLA2) comprises a superfamily of enzymes that hydrolyse the ester bond of phospholipids at the sn-2 position. Among the members of this superfamily, cytosolic PLA2 has attracted attention because it preferentially hydrolyses arachidonoyl phospholipids and is activated by submicromolar concentrations of Ca2+ ions and by phosphorylation by mitogen-activated protein kinases (MAP kinases). Here we investigate the function of cytosolic PLA2 in vivo by using homologous recombination to generate mice deficient in this enzyme. These mice showed a marked decrease in their production of eicosanoids and platelet-activating factor in peritoneal macrophages. Their ovalbumin-induced anaphylactic responses were significantly reduced, as was their bronchial reactivity to methacholine. Female mutant mice failed to deliver offspring, but these could be rescued by administration of a progesterone-receptor antagonist to the mother at term. Considered together with previous findings, our results indicate that cytosolic PLA2 plays a non-redundant role in allergic responses and reproductive physiology.

AIDS pathogenesis: the role of accessory gene mutations, leading to formation of long-lived persistently infected cells and/or apoptosis-inducing HIV-1 particles

Human immunodeficiency virus type 1 (HIV-1) infection indirectly induces activation-dependent apoptosis in bystander immune CD4+ T-cells, a hallmark of AIDS pathogenesis. It is well known that this pathogenetic event is significantly correlated with a high virus load. Active viral replication occurs in HIV-1 asymptomatic carriers throughout all stages of clinical disease. Most of the HIV-1 in plasma is derived from short-lived infected cells with a half life of a few days; however, a minor population of virus is derived from long-lived persistently and latently infected cells. Recently, the importance of such latent reservoirs for HIV-1 has come to the forefront because of studies with potent antiretroviral inhibitors that block only new rounds of infection. An initial large drop in viral load occurs within two weeks as noted by a decrease in plasma viremia. This is then followed by a slower second-phase decay, since only a small fraction of latently infected resting CD4+ T-cells carry replication-competent, integrated provirus. This review highlights the mechanisms of apoptosis induction in bystander immune cells by both protease-defective, gp120-containing HIV-1 particles, as well as by wild-type virus that appears to be derived predominantly from long-lived infected cells. A model involving the NH2-terminal Nef domain (p7) in this 'bystander apoptosis' event is also presented.

Clinical investigation of the relationship between Borna disease virus (BDV) infection and schizophrenia in 67 patients in Japan

The relationship between Borna disease virus (BDV) infection and schizophrenia in the clinical time course was investigated. By nested reverse-transcribed polymerase chain reaction (RT-PCR) and Western blotting, BDV-specific RNA and anti-BDV antibodies were examined in the EDTA-treated blood from 67 schizophrenic patients (according to DSM-III-R) in Japan. A significantly higher proportion (45%) of anti-BDV antibody and/or BDV RNA carriers were found among these 67 schizophrenic patients than in 26 controls (0%). There were no apparent associations of BDV infection with age, age at onset, period of hospitalization, accompanying somatic diseases, a past history of tuberculosis, a history of transfusion, a family history, or doses of psychotropic drugs. It is possible that, at least, BDV infection in schizophrenic patients may not be a nosocomial (hospital-acquired) infection, although the route of BDV infection in humans remains unidentified. More studies on the relationship between BDV infection and clinical psychosomatic features should be performed in order to elucidate the pathogenesis of schizophrenia.

[Demonstration on Borna disease virus in patients with chronic fatigue syndrome]

Chronic fatigue syndrome (CFS), a recently named heterogeneous disorder, is an illness of unknown etiology. The association between CFS and several viral infection has been suggested. Here, we centered on the possible link between CFS and Borna disease virus (BDV) infection. BDV is a neurotropic, nonsegmented negative-strand (NNS) RNA virus. Recent epidemiological data have suggested that BDV may be closely associated with depression and schizophrenia in humans. In Japanese patients with CFS, the prevalence of BDV infection was 34% (30/89) and 12% (7/57) by immunoblotting and PCR analysis, respectively. Furthermore, anti-BDV antibodies and BDV RNA were detected in a family cluster with CFS. These results suggested that this virus contributes to or initiates CFS, although the single etiologic role of BDV is unlikely.