Search

It has been reported that Epstein-Barr virus (EBV) resides in resting B cells in vivo. However, an ideal in vitro system for studying EBV latent infection in vivo has not yet been established. In this study, a mantle cell lymphoma line, SP53, was successfully infected with a recombinant EBV containing a neomycin-resistant gene. The EBV-carrying SP53 cells were obtained by selection using G418. They expressed EBER-1, EBNAs, and LMP1; this expression pattern of the EBV genes was similar to that in a lymphoblastoid cell line (LCL). However, proliferation assay showed that the EBV-carrying SP53 cells have a doubling time of 73 h, compared with 57 h of SP53 cells. Transplantation of 10(8) SP53 cells to nude mice formed tumors in 4 of 10 mice inoculated, but the EBV-carrying SP53 cells did not. Unexpectedly, EBV infection reduced the proliferation and tumorigenicity of SP53 cells. However, the EBV-carrying SP53 cells showed higher resistance to apoptosis induced by serum starvation than did the SP53 cells. The inhibition of proliferation and the resistance to apoptosis induced in SP53 cells by EBV infection indicate that this cell line might to some extent provide a model of in vivo EBV reservoir cells.

We have developed a reliable internally controlled RT-nested PCR method for the detection of hepatitis C virus (HCV) RNA using in vitro synthesized Renilla luciferase (Rluc) RNA as an internal control. Using this method, the 5'-noncoding region of HCV RNA (144 nucleotides) and Rluc RNA (276 nucleotides) were efficiently amplified in a single tube, and the sensitivity and specificity of this method were comparable to standard RT-nested PCR. This method was successfully performed on RNA specimens obtained from in vitro HCV-infected human hepatocyte PH5CH8 cells, which support HCV replication. In addition, we demonstrated that this method was useful for the evaluation of antiviral reagents by confirming the anti-HCV activity of bovine lactoferrin, which we previously found to be a new inhibitor of HCV infection. Therefore, this method may be useful for the studies of not only HCV but also of other viruses.

A patient with a diffuse, small cleaved cell, non-Hodgkin's lymphoma associated with marked hypecalcemia was described. Antibody to the adult T-cell leukemia-lymphoma virus was absent. Although bone marrow was infiltrated by lymphoma cells, destructive or lytic bone lesions could not be detected. The serum level of immunoreactive parathyroid hormone C-terminal (PTH-C) was normal. The serum level of 1, 25-dihydroxyvitamin D was lower than normal. This case suggests that other humoral substances produced by lymphoma cells may be responsible for hypercalcemia.</P>

The hepatitis B virus surface antigen containing the preS2 nine amino acid sequence produced by a recombinant Saccharomyces cerevisiae (yHBsAg) was purified and its physicochemical properties were determined. Ultrastructurally, the yHBsAg was found to be a homogeneous spherical particle with a diameter of 24 +/- 4 nm. The homogeneity of the yHBsAg particles was also demonstrated by analyses of their buoyant density and isoelectric point. They consisted of protein (53%), lipid (36%) and carbohydrate (11%), and the alpha-helix content was estimated to be 32%, differing from the reported values for human plasma-derived HBsAg (hHBsAg). Immunodiffusion analysis showed that the antigenic specificity of yHBsAg was identical to that of hHBsAg. Immunization of mice demonstrated that the immunogenicity of the yHBsAg was significantly higher than that of hHBsAg.

In order to elucidate the mechanism of latent infection of herpes simplex virus (HSV), reactivatable latency of three avirulent strains (SKO-1B, -GCr Miyama, SKa) of HSV type 1 was comparatively examined in a mouse latency model. The SKO-1B strain showed high rate of virus reactivation from explanted trigeminal ganglia without n-butyrate enhancement, while the other two strains showed a very low rate of virus reactivation in the absence of n-butyrate. In the presence of n-butyrate, however, the rate of the -GCr Miyama strain jumped to a comparable level with that of SKO-1B, although the rate of SKa remained at a low level. A more precise follow-up experiment changing the virus dose highlighted the difference of the ability to reactivate from the latent state between SKO-1B and -GCr Miyama. Virus titer in trigeminal ganglia during acute phase, infectivity to cell lines of neural origin, and susceptibility to acyclovir and phosphonoacetate were assayed to know the reasons for the variation in the ability of reactivatable latency among these strains. It was concluded that the reduced infectivity to neural cells, and limited ability of reactivatable latency shown by the SKa strain could mainly be attributed to the deficiency of thymidine kinase activity.</P>

<P>Peripheral T-cell lymphoma (PTL) is a distinctive clinical entity, albeit it comprises several diseases with histologically heterogeneous diagnoses. We studied prognostic factors on 30 patients diagnosed and treated at Shikoku Cancer Center Hospital. Clinical findings and laboratory data were evaluated by statistical analysis to investigate the important factors influencing survival duration. Variables influencing survival were stage, leukemic change, bone marrow infiltration (BMI), anti-human T-lymphocyte virus-type I antibody, white blood cell count, and lactate dehydrogenase (LDH). Multivariate analysis revealed high level of LDH and positive BMI as the important factors for short survival. Histological classifications of the Working Formulation and the T-lymphoma classification by Suchi et al. were also evaluated whether these were related with prognosis. Our data revealed that there was no significant relationship between histological subtype and survival duration. The study of prognostic factors provides valuable aids for us to understand the clinical characteristics of PTL patients with various backgrounds.

Trial of Rous sarcoma virus (RSV) induction by cell fusion with chick embryo cells (CEC) and wing web test from so-called RSV-transformed human cells, KC and RSb cells, was unsuccessful. The loss of RSV inducibility was also confirmed by DNA transfection method. Southern blot and northern blot hybridization of DNA and RNA from those cells with the v-src probe revealed that the v-src genes in those cells were defective and not expressed. On the other hand, the v-src gene in RSV-transformed mouse and rat cells was complete and transforming virus was inducible from them.</P>

Ability of two neurovirulent strains (F and +GC (LPV) Miyama) of herpes simplex virus type 1 (HSV-1) to establish and maintain reactivatable latency in trigeminal ganglia (TG) was compared after intranasal inoculation of mice. The +GC (LPV) Miyama strain showed a very low rate of virus reactivation in explant cultures of TG, while the F strain showed a high rate of reactivation. These data indicate that neurovirulent strains of HSV-1 are not always competent for reactivatable latency, although most virulent strains of HSV-1 thus far reported were competent for reactivatable latency.</P>

Immune responses to hepatitis B virus (HBV) vaccine in six low- or non-responded health-care workers were tested with an intradermal low dose (5 micrograms) of the recombinant vaccine. The injection was repeated three or four times at fortnightly intervals. These successive doses of the vaccine induced a high concentration of antibodies with delayed-type hypersensitivity (DTH) skin reactions in all six subjects. A few minor temporary side effects, such as irritation and itching at the injection site, were reported by some of the vaccinees. The results suggest low-dose of intradermal HBV vaccinations for low- or non-responders are safe and readily effective.

A 34-year-old woman infected with human T cell leukemia virus type-I(HTLV-I) with recurrent thrombocytopenia and various autoantibodies is described. The platelet counts fluctuated between 1.3 x 10(4)/microliters and 14.8 x 10(4)/microliters without any medical treatment, and thrombocytopenia improved with a decrease of platelet-associated IgG (PA-IgG). Autoantibodies such as rheumatoid factor, antinuclear factor, anti-Sm, anti-RNP and anti-SSA antibodies were also recognized. Marker analysis of peripheral mononuclear cells showed an increase in the proportion of CD 25+ cells, CD 3+ HLA-DR+ cells, CD4+ HLA-DR+ cells and CD8+ HLA-DR+ cells. The recurrent thrombocytopenia and development of various autoantibodies in this HTLV-I carrier are speculated to be due to the alteration of B cell functions by T cells infected with HTLV-I.

Genetic variation of hepatitis C virus was assessed. We prepared RNA fractions from 21 patients' sera which were positive for hepatitis C virus RNA, synthesized their cDNAs, and amplified fragments, 406 base pairs, encoding a putative core protein, by polymerase chain reaction. One of them, N 15, was cloned and sequenced. N 15 showed 92.4% homology at the nucleotide level and 97.0% homology at the amino acid level compared with HC-J 1 which is the first isolated clone in Japan and similar to that isolated in USA. By restriction fragment length polymorphisms analysis, 14 out of 21 patients (66.7%) showed the same pattern as N 15. No patients showed the pattern of HC-J 1. We could not find a correlation between the genetic variation and clinical features of hepatitis C virus infection. These results indicate that the region, which encodes the core protein and is believed to be relatively conserved in hepatitis C virus genome, has several variations at the nucleotide level, and the major part of hepatitis C virus in Okayama district is different from HC-J 1 and the USA clone.

Epstein-Barr virus (EBV)-related herpesvirus (Si-IIA-EBV) was serially transmitted for 3 passages from rabbit to rabbit of the opposite sex by blood transfusion, which subsequently induced virus-associated rabbit lymphomas. The virus could be transmitted by transfusion with 15-20 ml of whole blood (7/7) or irradiated blood (1/6) from the EBV-related virus-infected rabbits, but there was no transmission with transfusion of cell-free plasma (0/6) from the infected rabbits. Passive anti-EBV-VCA IgG (x 20 approximately x 10) titers decreased during the first 1-2 weeks in the transfused rabbits. The virus-transmitted rabbits showed a gradual increase in antibody titers ranging from peak titers of x 640 to x 2560 after 3 weeks of transfusion. The recipient origin of malignant lymphoma that developed in the first rabbit transfused by infected blood was confirmed by chromosomal analysis. This rabbit model thus shows that EBV-related herpesvirus is serially transmissible by blood transfusion and that transmission can not be completely prevented by irradiation of blood, but removal of blood cells is the best way to prevent transmission of EBV-related virus. Therefore, this animal model provides a convenient in vivo system for studies of the prevention and therapy of transfusion-related transmission of EBV and EBV-associated lymphoproliferative diseases in immunocompromised human beings.

Epstein-Barr virus (EBV), or human herpesvirus 4 (HHV-4), infects the vast majority of adults worldwide, and establishes both nonproductive (latent) and productive (lytic) infections. Host immune responses directed against both the lytic and latent cycle-associated EBV antigens induce a diversity of clinical symptoms in patients with chronic active EBV infections who usually contain an oligoclonal pool of EBV-infected lymphocyte subsets in their blood. Episomal EBV genes in the latent infection utilize an array of evasion strategies from host immune responses: the minimized expression of EBV antigens targeted by host cytotoxic T lymphocytes (CTLs), the down-regulation of cell adhesion molecule expression, and the release of virokines to inhibit the host CTLs. The oncogenic role of latent EBV infection is not yet fully understood, but latent membrane proteins (LMPs) expressed during the latency cycle have essential biological properties leading to cellular gene expression and immortalization, and EBV-encoded gene products such as viral interleukin-10 (vIL-10) and bcl-2 homologue function to survive the EBV-infected cells. The subsequent oncogenic DNA damage may lead to the development of neoplasms. EBV-associated NK/T cell lymphoproliferative disorders are prevalent in Asia, but quite rare in Western countries. The genetic immunological background, therefore, is closely linked to the development of EBV-associated neoplasms.

Sera from 84 patients with chronic liver disease [CLD] (74 chronic active) and from 53 blood donors were tested immunochemically for anti-liver cell membrane antibody (LMAb). LMAb to rat liver tested by an indirect immunofluorescent technique was positive in 53.3% of CLD patients with positive HB surface antibody (HBsAb) and 40.0% of HBsAb positive blood donors. Pepsin digestion of the sera indicated that the binding between liver cell membrane and IgG was at the Fc site on the immunoglobulin. The sera with positive LMAb from HBsAb positive blood donors had elevated Clq-binding activity (Clq-BA). The LMAb to rat liver was a macro-molecular IgG (19-22S IgG) when assayed by Sephadex G-200 column chromatography and 5-40% sucrose density gradient ultracentrifugation. The results suggest that the LMAb in serum from a patient with chronic active liver disease may be an immune complex which consists of various antigens such as HB virus and its antibodies in serum.

Human cells derived from malignant tumors (HeLa, HEp-2 and KB) and human cells transformed by tumor viruses (KCand RSb) formed syncytia by simian sarcoma virus type I (SSV-I/SSAV-I), but human diploid or non-transformed cells (WI-38, HEL and HEC) did not.

RNA polymerase was extracted from the Schmidt-Ruppin strain of Rous sarcoma virus (SR-RSV)-induced C3H/He mouse ascites sarcoma cells (SR-C3H). RNA polymerase was separated into RNA polymerases I and II by DEAE-Sephadex chromatography. RNA polymerase I was separated into Ia and Ib fractions by phospho-cellulose chromatography. In SR-C3H cells RNA polymerase Ib was the main component of RNA polymerase I. At 0.05--0.1 M ammonium sulphate RNA polymerase I transcribed native DNA most actively, and RNA polymerase II transcribed denatured DNA most actively. Partial digestion of DNA by DNAase I enhanced RNA synthesis by RNA polymerases I and II. At ionic strength over 0.2 M ammonium sulphate, the initiation reaction of RNA polymerases I and II was inhibited. The initiation complexes of RNA polymerases I and II with native DNA were more stable against high salt concentration than with denatured DNA.

A study of 52 liver biopsies (47 hepatitis type B and 5 asymptomatic carriers) was performed to clarify the roles of HBe antigen (HBeAg), HB surface antigen (HBsAg) and HB core antigen (HBcAg). In this study, the Gudat classification was modified so as to classify the patterns of HB antigens into six reaction types including: type O (negative for both liver HBsAg and liver HBcAg), type III-A (characterized by a spotty HBsAg pattern) and type III-B (characterized from a sub-lobular to lobular HBsAg localization pattern). This classification enabled accurate prediction of the prognosis of hepatitis. Patients with positive serum HBeAg had either minimal hepatitis with mild clinical features or chronic aggressive hepatitis with severe clinical features. Ten patients negative for both HBeAg and HBeAb were all positive for liver HBcAg. In all 3 patients on corticosteroid administrations liver tissue was markedly positive for HBcAg and serum was usually positive for HBeAb.

In order to locate the target cells for malignant transformation by BK virus (a human papova virus) in hamster brain, electron microscopic observation of tumor originally induced in hamster brain by BK virus was performed. With light microscopy, the BK virus-induced tumor (Vn 17) bore a close resemblance to human malignant ependymoma. Under the electron microscope, numerous microvilli and few cilia were visible on the surface of the tumor cells. These tumor cells were joined to each other by desmosomes. Gap junctions were not observed. Multilayered cuboidal cells were observed around the lumen and blood vessels in the tumor. With regard to fine structure, three types of Vn 17 cells were recognized; ependymal like cells, tanycytes with prominent cell processes, and undifferentiated cells with few cytoplasmic organelles. There was no basal lamina between the ependymal cells and the connective tissue stroma. The Vn 17 cells showed some similarity to the ultrastructural features of the epemdymal cells of newborn rabbits, suggesting that the target cells for Vn 17 may be cells related to ependyma. Malignant transformation of the cells would be initiated in the early stages after BK virus inoculation into the brain of newborn hamsters.