Isolation of a new virus, HBLV, in patients with lymphoproliferative disorders.

A novel human B-lymphotropic virus (HBLV) was isolated from the peripheral blood leukocytes of six individuals: two HTLV-III seropositive patients from the United States (one with AIDS-related lymphoma and one with dermatopathic lymphadenopathy), three HTLV-III seronegative patients from the United States (one with angioimmunoblastic lymphadenopathy, one with cutaneous T-cell lymphoma, and one with immunoblastic lymphoma), and one HTLV-III seronegative patient with acute lymphocytic leukemia from Jamaica. All six isolates were closely related by antigenic analysis, and sera from all six virus-positive patients reacted immunologically with each virus isolate. In contrast, only four sera from 220 randomly selected healthy donors and none from 12 AIDS patients without associated lymphoma were seropositive. The virus selectively infected freshly isolated human B cells and converted them into large, refractile mono- or binucleated cells with nuclear and cytoplasmic inclusion bodies. HBLV is morphologically similar to viruses of the herpesvirus family but is readily distinguishable from the known human and nonhuman primate herpesviruses by host range, in vitro biological effects, and antigenic features.

Low numbers of intestinal Shiga toxin-producing E. coli correlate with a poor prognosis in sheep infected with bovine leukemia virus.

Healthy ruminants carry intestinal Shiga toxin (Stx)-producing Escherichia coli (STEC). Stx has antiviral activities in vitro and STEC numbers correlate with reduced early viremia in sheep experimentally infected with bovine leukemia virus (BLV). This study assessed the impact of intestinal STEC on BLV-induced disease for one year post-BLV-challenge. High STEC scores (CFU/g feces x frequency of STEC-positive samples) correlated with good health, whereas poor weight gain, distress, and tumor development occurred only among animals with low STEC scores. STEC carriage was associated with increased percentages of B cells in peripheral blood.

Retroviruses and nervous system disease.

During the past decade retroviruses have been recognized as causes of human neurological disease. A wide clinical spectrum of neurological and neuromuscular diseases have been reported with HIV infections, and studies of these diseases have raised novel and exciting hypotheses of pathogenesis. As yet the full clinical spectrum of diseases associated with HTLV-1 has yet to be defined, and the pathogenesis of the chronic spastic paraparesis remains a mystery. Chronic neurological diseases in animals caused by both oncoviruses and lentiviruses can provide some clues to the pathogenesis of these newly recognized human neurological illnesses.

Development of adult T-cell leukemia-like disease in African green monkey associated with clonal integration of simian T-cell leukemia virus type I.

Proviral integration of a simian retrovirus highly homologous to human T-cell leukemia virus type I was examined in cellular DNAs extracted from primary peripheral blood lymphocytes of 31 adult African green monkeys (Cercopithecus aethiops) that were seropositive for simian T-cell leukemia virus type I (STLV-I). Among these monkeys, one case with overt leukemia, showing pleomorphic leukemia cells similar to those in human adult T-cell leukemia (ATL), and five cases in a preleukemic state of ATL-like disease were found. Judging from the integration site of the provirus genome, primary lymphocytes of these leukemic or preleukemic cases contained monoclonally proliferated STLV-I-infected cells, whereas lymphocytes of other seropositive monkeys without hematological abnormalities were polyclonal, and those of seronegative monkeys did not contain the provirus. The restriction patterns with PstI ans SstI of most STLV-I proviruses were identical to those of the previous isolate from this species, but in three monkeys there was a deletion of one PstI site. From the correlation of the development of simian ATL-like disease with the monoclonal integration of the STLV-I provirus genome, it should be indicated that STLV-I has similar leukemogenicity to human T-cell leukemia virus type I, and so STLV-I infection in African green monkeys will be useful as an animal model of human ATL.

Lack of evidence for a role of T-cell-associated retroviruses as an etiology of schizophrenia.

The evidence that schizophrenia may involve infection by a virus (or viruses) has been indirect. The recent discovery, however, of the human retroviruses--human T-cell lymphoma-leukemia virus-I, and II (HTLV-I, -II) and human immunodeficiency virus (HIV)--now also known to affect the central nervous system (CNS), together with the development of new techniques in retrovirology, have made it possible to investigate more directly the role of this class of viruses as an etiology of schizophrenia. In our first effort to screen for the presence of a T-cell lymphotropic virus in schizophrenia, short-term tissue cultures of peripheral lymphocytes from 17 chronic schizophrenic patients and 10 normal controls were established. The cells were cultured in the presence of T-cell growth factor (TCGF, IL-2), and the culture supernatants were tested for the presence of the retroviral enzyme reverse transcriptase. No T-cell-associated reverse transcriptase activity was detected in cultures from patients or normal controls. Therefore, the data do not provide evidence for a role for T-cell lymphotropic retroviruses as an etiology of schizophrenia.

Human T cell lines established from the cerebrospinal fluid of patients with human T lymphotropic virus type I-associated myelopathy (HAM).

T cell lines were established from the cerebrospinal fluid (CSF) lymphocytes of two patients with human T lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM). These two interleukin-2 (IL-2)-dependent T cell lines have been cultured for more than 8 months without any accessory cells. The surface phenotype of these cells was CD2(+), CD4(+), CD8(-), Ia(+) and Tac(+). Southern blot hybridization analysis revealed the presence of HTLV-I provirus in these cells and C-type retrovirus particles were identified by electron microscopy. These findings indicate the presence of HTLV-I infected helper T lymphocytes in the CSF of the patients with HAM. These HTLV-I(+) T cell lines may be valuable for investigating the possible neutrotropism of HTLV-I and the role of HTLV-I in the pathogenesis of HAM.

HTLV-I infection of cerebrospinal fluid T cells from patients with chronic neurologic disease.

Antibodies reacting with HTLV-I, the etiologic agent of acute T cell leukemia/lymphoma and a transforming agent for T4-positive lymphocytes in vitro, have recently been described in sera of patients with chronic neurologic disease in the absence of lymphoproliferative disorders. The largest number of such cases was described in Japan and in the Caribbean and parts of South America. We report here two cases of patients with chronic neurologic disease whose cerebrospinal fluid (CSF)-derived T cells contain HTLV-I specific RNA sequences and antigens and are expressing retroviral particles. Only one of these patients has demonstrable antibody to HTLV-I in serum or CSF.

The origins of HIV-1 and HTLV-4/HIV-2.

PIP: More sophisticated knowledge of the different strains of seemingly closely related retroviruses is essential to understanding acquired immunodeficiency syndrome (AIDS) and developing a successful vaccine. Distinct exogenous human retroviruses include human immunodeficiency virus type 1 (HIV-1), the etiologic agent in AIDS; human T-lymphotropic virus type 1 (HTLV-1), which has been linked with adult T-cell leukemia/lymphoma; and HTLV-II, a virus closely linked to HTLV-I but not definitively implicated in human disease. Closely related to HIV-1 is simian T-lymphotropic virus type 3 (STLV-3 mac). 30-70% of over 1000 African green monkeys tested possess antibodies to STLV-3 proteins. Of interest is the contrasting pathogenicity of HTLV-3 in seropositive Asian macques and African green monkeys; the former always have clinical or pathological evidence of immunosuppressive disease, while the latter remain healthy. Given the apparent ability of African green monkeys to mount an effective immune response against infection with STLV-3, this retrovirus offers a model system for the study of AIDS pathogenesis. It was hypothesized that STLV-3 is a distant progenitor of the AIDS virus, and that HIV-1 may have originated in Africa through the chance transmission of a simian virus to humans. A 4th human T-lymphotropic retrovirus, isolated from healthy Senegalese prostitutes in 1985 and termed HTLV-4/HIV-2, has viral proteins similar to those of STLV-3 and HIV-1. Although HTLV-4/HIV-2 is prevalent among high risk groups in West Africa, it is not associated with immunosuppression; this suggests a unique species-specific pathogenicity similar to that in STLV-3.^ieng

Failure to detect human T-lymphotropic virus antibody in wild-caught New World primates.

We conducted a study to look for a simian counterpart of human T-lymphotropic virus (HTLV) in wild-caught monkeys in the Republic of Panama. Serum specimens were obtained from 102 monkeys (Ateles fusciceps, n = 75; Alouatta villosa, n = 18; and Cebus capucinus, n = 9) captured in Panama's Darien rain forest in 1979-1980. Specimens were screened for HTLV antibody by enzyme-linked immunosorbent assay, and reactive specimens were further tested by Western blot. None of the 102 specimens were seropositive for HTLV. Our findings provide no evidence for an HTLV-like virus in New World primates from Panama, but the sample size was small, and further studies are warranted.

Clinical and molecular parameters of HTLV-I infection.

The elucidation of the spread of HTLV-I through high-risk groups and the finite but real incidence of HTLV-I seropositivity in normal blood donor populations in the United States indicates that blood and blood products should be screened for this infectious agent. Because of the ability of the provirus to exist in a quiescent state and the long lag time between exposure and seroconversion, it may be necessary to screen potential blood donors for integrated sequences by gene amplification methodologies in addition to standard serologic testing to protect the blood supply. The detection of the HTLV-I virus often requires multiple modes of testing, even in ATL patients. We have characterized by gene amplification several HTLV-I positive lymphoma patients who were seronegative. We have also identified by radioimmunoprecipitation assays intravenous drugs abusers who have antibody solely to the nuclear pX gene product and who do not, therefore, test positive in an ELISA assay prepared from purified virion proteins. All HTLV-I positive patients need to be counseled about the biohazard status of their body fluids. The fact tha only 1 to 2 per cent of HTLV-I infected persons have any diagnosable disease, coupled with the knowledge that the mean time for the onset of clinical manifestations is some 20 to 30 years following conversion to seropositivity, indicates that this is not a virulent pathogen or a highly transforming virus. These epidemiologic data support the notion of HTLV-I's role as a mitogen or first lesion in a multistep pathway to malignancy. These data are also consistent with the idea of rare random cis-activation of one of many cellular oncogenes following a fortuitous integration event.

Viruses in the pathogenesis of systemic lupus erythematosus.

In spite of the lack of firm evidence implicating infectious agents, it is still likely that SLE requires an initiating event, probably environmental, and possibly infectious. In the setting of genetically determined perturbations of the immune system, an infectious trigger could be a trivial event clinically, and could be different in different patients. Once triggered, the immunologic abnormalities might be self-perpetuating so that the persistent infection and foreign antigens as found in hepatitis B vasculitis, might not be needed in SLE. Current evidence has not firmly implicated any specific microbial agents, but on a theoretical basis, the human retroviruses are particularly attractive candidates.

Epidemiology and etiopathology of human T-lymphotropic viruses: diagnostic and clinical implications for non-endemic areas.

Human T-lymphotropic viruses (HTLV) type I and II were first described more than a decade ago. HTLV-I epidemiology and etiopathology are more defined than those of HTLV-II, but conflicting results have been obtained in seroepidemiologic surveys, mainly for difficulties in the discrimination between the two infections. The introduction of advanced serologic and molecular assays has recently provided sensitive and specific tools for diagnosis, and the epidemiologic and etiopathologic patterns linked to these retroviruses are being more precisely defined. Moreover, extensive nucleotide sequence analyses performed so far have mainly focused on HTLV-I isolates. The recent discovery of new HTLV-II endemic areas and the isolation of HTLV-II strains from intravenous drug users have finally provided the material for the molecular characterization of HTLV-II isolates, which is now a rapidly envolving field. We review the diagnostic strategies available and the etiologic associations reported so far for both viruses and also discuss the occurrence and significance of indeterminate serologic reactivities observed in both endemic and non-endemic areas.

Human T-lymphotropic virus type I (HTLV-I) provirus-related DNA sequences in peripheral blood mononuclear cells of a patient, in the absence of a definite serological positivity.

The true extent of human T-lymphotropic virus type I and II (HTLV-I/II) infection in European countries and its pathogenetic potential are still unknown. To find out more about HTLV-I/II incidence in our area we studied a group of 160 outpatients attending a sexually transmitted disease clinic over a six-month period. All patients were screened for the presence of specific antibody by means of enzyme-linked immunosorbent assay (ELISA) and immunoblotting (IB) analysis, using commercially available reagents. A surprisingly high percentage of patients showed an antibody reactivity to HTLV-I/II antigens by ELISA (9.3%) and IB (6.8%), although none of the samples satisfied the internationally accepted criteria of serological positivity. All subjects, irrespective of doubtful and inconclusive serological results, were further analyzed for the presence of proviral DNA in peripheral blood mononuclear cells by polymerase chain reaction using different pairs of primers and probes. A clear cut positive result for the presence of HTLV-I provirus-related DNA sequences was obtained in peripheral blood mononuclear cells of only one patient, a 26 years old female presenting genital condylomatosis, with no history of blood transfusion and/or intravenous drug abuse. Her serum showed a borderline result at ELISA and an IB reactivity only against p21. These data are open to various possible interpretations and, among others, may represent a hint for the presence of divergent antigenic variants of HTLV-I in the geographical area investigated.

[A new variant of the simian T-lymphotropic retrovirus type I (STLV-IF) in the Sukhumi colony of hamadryas baboons]. / Novyi variant obez'ian'ego T-limfotropnogo retrovirusa pervogo tipa (STLV-1F) v Sukhumskoi kolonii pavianov gamadrilov.

Polymerase chain reaction (PCR) was developed for the detection of simian T-lymphotropic virus type 1 (STLV-1) infection of P. hamadryas and direct sequencing using oligo-nucleotide primer pairs specific for the tax and env regions of the related human T-lymphotropic virus type 1 (HTLV-1). Excellent specificity was shown in the detection of STLV-1 provirus in infected baboons by PCR using HTLV-1-derived primers. The nucleotide sequences of env 467bp and tax 159bp of the proviral genome (env position 5700-6137, tax position 7373-7498 HTLV-1, according to Seiki et al., 1983) derived from STLV-1-infected P. hamadryas were analysed using PCR and direct sequencing techniques. Two STLV-1 isolates from different sources (Sukhumi main-SuTLV-1 and forest stocks-STLV-1F) were compared. Two variants of STLV-1 among P. hamadryas with different level of homology to HTLV-1 were wound (83.8% and 95.2%, respectively). A possible role of nucleotide changes in env and tax sequenced fragments and oncogenicity of STLV-1 variants is discussed.

[Rat lymphoid cell lines producing human T cell leukemia virus-I].

Cocultivation of spleen cells, lymph node cells, and thymocytes of female Wistar-King-Aptekman rats with short-term cultured male adult T cell leukemia (ATL) cells in the presence of 5-bromo-2'-deoxyuridine (BudR) resulted in the establishment of rat lymphoid cell lines, TARS-1, TARL-2, and TART-1. Cytogenic analysis of the three cell lines showed a female rat karyotype with 42 chromosomes. The surface phenotypes of TARS-1 and TART-1 were those of rat T cells. TARL-2 was only positive for rat Ia and leukocyte common antigens and brain associated T antigen. The cell lines continuously produced a type C retrovirus, human T cell leukemia virus-I (HTLV-I) and expressed ATL-associated antigens. By using monoclonal antibodies for rat IL-2 receptors, FACS analysis demonstrated that three rat T cell lines unequivocally expressed rat IL-2 receptor. TARS-1 and TART-1 but not TARL-2 were transplantable into newborn syngeneic rats and nude mice. By injecting MMC-treated TARS-1 into newborn syngeneic rats, HTLV-I carrier rats were obtained which showed gradual increase of anti-ATLA antibody titer by aging. No evidence of leukemia nor malignant lymphoma were observed in those carrier rats. Adult rats immunized with these rat cell lines produced antibodies specific for HTLV-I. The biochemical analysis of the antigen that reacted with rat sera revealed that they are the HTLV-I specific polypeptides, p28, p24, p19 and p15.