The isolation of a T-cell tropic retrovirus from three immunodeficient macaques and one macaque with lymphoma is described. The morphology, growth characteristics, and antigenic properties of this virus indicate that it is related to the causative agent of acquired immune deficiency syndrome in humans (HTLV-III or LAV). This virus is referred to as simian T-lymphotropic virus type III (STLV-III) of macaques. The existence of a cytopathic, T-cell tropic virus resembling HTLV-III in monkeys may facilitate study of disease induction and vaccine development in an animal model.

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 transmission of adult T cell leukemia virus, a human retrovirus, into fresh leukocytes from normal humans was examined. One of three virus-carrying cell lines, tested after being subjected to lethal x-irradiation, consistently transformed leukocytes from adult peripheral blood and umbilical cord blood. All the transformed cell lines expressed adult T cell leukemia virus-associated antigen, but transformed lines originating from adult and umbilical cord blood exhibited T cell and non-T, non-B cell surface natures, respectively. Efforts to transform human leukocytes with cell-free virus were unsuccessful.

Human immunodeficiency virus type 1 integrase (HIV-1 IN) is thought to have several putative roles at steps prior to integration, such as reverse transcription and nuclear transport of the preintegration complex (PIC).Here, we investigated new functional aspects of HIV-1 IN in the context of the viral replication cycle through point mutagenesis of Ser, Thr, Tyr, Lys, and Arg residues conserved in IN, some of which are located at possible phosphorylation sites. Our results showed that mutations of these Ser or Thr residues had no effect on reverse transcription and nuclear transport of PIC but had a slight effect on integration. Of note, mutations in the conserved KRK motif (amino acids 186 to 189), proposed previously as a putative nuclear localization signal Retroviruses establish a proviral state in which a doublestranded DNA copy of the viral genomic RNA is integrated into the host genome in a stable manner, through several steps following binding and entry into the target cell. These early events include uncoating, reverse transcription, nuclear transport of the viral genome, and integration. The viral enzyme integrase (IN) is encoded by the pol gene and the attachment (att) site located at the U3 and U5 termini of the viral DNA and is required for integration, which is the last event (6,14,43,47,53,56,57,61,66,74). The detailed mechanism of retroviral integration has been elucidated from in vitro studies using recombinant IN protein and a synthetic DNA substrate mimicking the viral att sites. These studies, using in vitro assays, have contributed much information toward the currently accepted mechanism of retroviral integration (reviewed in references 34, 42, and 75). Mutational and structural studies of human immunodeficiency virus type 1 (HIV-1) IN have identified three functional domains: a central catalytic core domain, an N-terminal zinc binding domain, and a C-terminal nonspecific DNA binding domain. The core domain contains the highly conserved D,D35E motif, which is directly involved in the catalytic activities of IN (7,23,46,48). The N-terminal domain contains a highly conserved HHCC motif, which binds to zinc. Through a tetrahedral attachment to the HHCC motif, zinc enhances both multimerization and enzymatic activities of 8,21,79). The C terminus, consisting of a structure that closely resembles Src homology 3 domains, possesses sequence-and metal ion-independent DNA binding activity (20,51). Each domain has been demonstrated to form a dimer or higher multimerization state of IN (8,19,20), which might be required for its full activity (13,21,22,66,70,73).Genetic analysis of HIV-1 IN has demonstrated multiple effects of mutations at steps distinct from integration. These steps include correct viral particle formation (24, 59), uncoating (54, 59), and reverse transcription (49,54). During the early events of the infection cycle, prior to integration, around 50-100 protomers of IN exist as one of the major components of the preintegration complex (PIC). This is composed of the viral genome, the matr...

ABSTRACT

Severe acute respiratory syndrome (SARS) is characterized by rapidly progressing respiratory failure resembling acute/adult respiratory distress syndrome (ARDS) associated with uncontrolled inflammatory responses. Here, we demonstrated that, among five accessory proteins of SARS coronavirus (SARS-CoV) tested, 3a/X1 and 7a/X4 were capable of activating nuclear factor kappa B (NF-jB) and c-Jun N-terminal kinase (JNK), and significantly enhanced interleukin 8 (IL-8) promoter activity. Furthermore, 3a/X1 and 7a/X4 expression in A549 cells enhanced production of inflammatory chemokines that were known to be up-regulated in SARS-CoV infection. Our results suggest potential involvement of 3a/X1 and 7a/X4 proteins in the pathological inflammatory responses in SARS.

Sixteen patients with adult T-cell leukemia/ lymphoma (ATL) who were all over 50 years of age underwent allogeneic stem cell transplantation with reduced-conditioning intensity (RIST) from HLA-matched sibling donors after a conditioning regimen consisting of fludarabine (180 mg/m 2 ), busulfan (8 mg/ kg), and rabbit antithymocyte globulin (5 mg/kg). The observed regimen-related toxicities and nonhematologic toxicities were all found to be acceptable. Disease relapse was the main cause of treatment failure. Three patients who had a relapse subsequently responded to a rapid discontinuation of the immunosuppressive agent and thereafter achieved another remission. After RIST, the human T-cell leukemia virus type 1 (HTLV-1) proviral load became undetectable in 8 patients. RIST is thus considered to be a feasible treatment for ATL. Our data also suggest the presence of a possible graftversus-ATL effect; an anti-HTLV-1 activity was also found to be associated with this procedure. IntroductionTherapeutic trials to improve the dismal prognosis of adult T-cell leukemia/lymphoma (ATL) among elderly persons who are infected with human T-lymphotropic virus type 1 (HTLV-1) have so far been unsuccessful. 1-5 However, there have been a few encouraging reports on allogeneic stem cell transplantation (alloSCT) for selected populations of patients with ATL. [6][7][8][9] Although most of the patients who were treated successfully in these studies received grafts from HLA-identical siblings and the patients were younger than the average age for patients with ATL, the main cause of treatment failure after alloSCT remains transplant-related complications such as acute graft-versus-host disease (aGVHD). Recent advances have now allowed alloSCT to be extended to older patients through the use of reduced-intensity conditioning regimens. [10][11][12] We therefore conducted a phase 1 clinical trial of alloSCT with reducedconditioning intensity (RIST) to clarify whether this newly developed procedure is feasible for ATL patients over 50 years of age. Study designThe eligible patients ranged from 50 to 70 years of age and met the diagnostic criteria for ATL. 13 The patients were required to be in either complete remission (CR) or partial remission (PR) at the time of registration 5 and to have an HLA-identical sibling donor. All patients and donors gave their written informed consent to participate in this study, which was approved by the institutional review board of each participating institution.The conditioning regimen consisted of fludarabine (180 mg/m 2 ), busulfan (8 mg/kg), and rabbit antithymocyte globulin (ATG; 5 mg/kg) as reported. 10 Granulocyte colony-stimulating factor-mobilized peripheral blood (PB) grafts from the donors were transplanted. To prevent GVHD, cyclosporine (CsA) was administered intravenously (3 mg/kg/d). The severity of GVHD was graded according to the consensus criteria. 14 The degrees of donor-recipient chimerism and HTLV-1 proviral DNA in PB mononuclear cells (MNCs) were quantified according to published met...

Human T-cell leukemia/lymphoma virus (HTLV)-carrying cells from various origins were characterized by cell surface markers and expression of HTLV antigens. Eight cell lines named TCL were obtained by transformation of peripheral blood leukocytes (PBL) of healthy donors or HTLV carriers in cocultures with HTLV-producer MT-2 cells. Nine cell lines named ILT were interleukin 2 (IL2)-dependent cell lines cloned from PBL of ATL patients and healthy HTLV-carriers. Tc-Kan9 cell line was also an IL2-dependent cell line clonally established from PBL culture stimulated with autologous TCL cells. Five cell lines named TL were established in vitro directly from PBL of an adult T-cell leukemia (ATL) patient and from ILT cells of an ATL patient and three HTLV-carriers, respectively, to grow autonomously without IL2. All the TCLs, ILTs, TLs and Tc-Kan9 possessed Leu-I antigen, a pan-T-cell marker. Leu3a antigen, a helper/inducer T-cell marker, was expressed on five of eight TCLs and all of the ILTs and TLs. Leu-2a, a cytotoxic/suppressor T-cell marker, was detected only on Tc-Kan9 but not others. Fresh ATL leukemic cells of patients had a helper/inducer T-cell marker. Ia, OKT9 and Tac antigens, markers for activated and differentiated T cells, were strongly expressed on all of the cell lines tested and fresh ATL leukemic cells were weakly positive for these antigens. Expression of HTLV antigens detected by mouse monoclonal antibodies and an ATL-patient serum varied among these cell lines. One TL, two ILTs and most of the fresh ATL leukemic cells did not express HTLV antigens on the cell surface. The other cell lines were all positive for the surface viral antigens. However, molecular species of antigens defined by radioimmunoprecipitation with an ATL-patient serum were not always identical among the cell lines. Molecular weights of polypeptides detectable in most of the cell lines were 62K, 46K, 40K, 24K, 21K and 19K which could never be detected in several control T-cell lines. 68K and 28K polypeptides were frequently detected in MT-2 and TGLs. GIN14, a mouse monoclonal antibody against HTLV core protein (p19) detected not only p19 in various cell lines but also p28, p29, p31 or p40 in certain cell lines tested. B-cell lines named LCL were established and cloned from PBL of two HTLV-carriers by EB-virus-induced transformation and they also expressed HTLV antigens, Ia, OKT9 and Tac antigens.(ABSTRACT TRUNCATED AT 400 WORDS)