Transformed T lymphocytes infected by a novel isolate of human T cell leukemia virus type II

Human T cell leukemia virus type II (HTLV-II) has been isolated from a patient (Mo) with features of leukemic reticuloendotheliosis (LRE) and from a patient with acquired immunodeficiency syndrome (AIDS). We have obtained another isolate of HTLV-II from a patient (CM) with severe hemophilia A, pancytopenia, and a 14-year history of staphylococcal and candidal infections but no evidence of T cell leukemia/lymphoma, AIDS, or LRE. Fresh mononuclear cells and cultured lymphocytes from CM express retroviral antigens indistinguishable by molecular criteria from HTLV-IIMo. Leukocyte cultures from CM yield hyperdiploid (48,XY, +2, +19) continuous lymphoid lines; human fetal cord blood lymphocytes (CBL) are transformed by cocultivation with these CM cell cultures but retain normal cytogenetic constitution. Electron microscopic examination of the CM cultures and transformed CBL reveals budding of extracellular viral particles, intracellular tubuloreticular structures, and viral particles contained within intracellular vesicles. CM cell cultures and the transformed CBL do not require exogenous interleukin 2, have T cell cytochemical features and mature T helper phenotypes, and exhibit minimal T helper and profound T suppressor activity on pokeweed mitogen-stimulated differentiation of normal B cells. These characteristics, which are similar to those observed with the first HTLV-II isolate, may represent properties of all HTLV-II-infected T cells.     

Cytokine production by endothelial cells infected with human T cell lymphotropic virus type I.

OBJECTIVE: To investigate the ability of human T cell lymphotropic virus type I (HTLV-I) to infect endothelial cells and induce cytokine production by these cells. METHODS: Human umbilical vein endothelial cells (HUVEC) were cocultured with HTLV-I infected T cell line (MT-2 cells) or uninfected T cell line (CEM cells). RESULTS: Following coculture with MT-2 cells, endothelial cells expressed HTLV-I specific core antigens. Endothelial cells cocultured with MT-2 cells produced significant amounts of several cytokines, including interleukin (IL)-1 alpha, IL-6, granulocyte colony stimulating factor (G-CSF), and granulocyte/macrophage colony stimulating factor (GM-CSF), compared with endothelial cells cocultured with CEM cells. Coculturing of endothelial cells with MT-2 and CEM cells failed to produce detectable amounts of IL-1 beta and tumour necrosis factor alpha (TNF-alpha). The production of cytokines by endothelial cells cocultured with MT-2 cells was more persistent than that by endothelial cells cocultured with CEM cells after several passages. Furthermore, the production was blocked by cocultivation of endothelial cells and MT-2 cells using the Millicell system. Finally, after cocultivation of endothelial cells and MT-2 cells, endothelial cells positive for HTLV-I antigen were stained by anti-GM-CSF antibody. CONCLUSIONS: HTLV-I can infect endothelial cells, resulting in their active production of several cytokines, such as IL-1 alpha, IL-6, G-CSF, and GM-CSF. These findings strongly suggest that the excess production of these cytokines by HTLV-I infected endothelial cells may be involved in the pathogenesis of HTLV-I associated inflammatory diseases.     

Simultaneous infections with human T cell leukemia virus type I and the human immunodeficiency virus

Four adults form four separate households were found to have simultaneous retroviral infections with human T cell leukemia virus type I (HTLV-I) and human immunodeficiency virus (HIV). These individuals were seropositive for the HTLV-I env transmembrane protein p21E, and all had antibodies to the HTLV-I core polypeptide p24. All four patients also had antibodies to the HIV env transmembrane polypeptide p41E and to the HIV core polypeptide p24. HTLV-I was isolated from peripheral blood lymphocytes of all four individuals, and both viruses were isolated from two of them. Evidence of HIV transmission was noted in the family contacts. Eight of 10 children of these four adults were seropositive for HIV, presumably because of perinatal transmission from infected mothers. Two of five spouses of these adults were examined; these spouses had antibodies to HIV and were positive for virus. No evidence of HTLV-I transmission was noted in these families.     

Characterization of T cells immortalized by Tax1 of human T-cell leukemia virus type 1

Peripheral blood T cells were immortalized in vitro by introduction of the Tax1 gene of human T-cell leukemia virus type 1 (HTLV-1) with a retroviral vector and were characterized for transformation-associated markers. Long-term observation showed that these Tax1-immortalized T cells eventually exhibited very similar features that were characteristic of HTLV-1-immortalized T cells, ie, increased expression of egr-1, c-fos, IL-2R alpha, and Lyn and decreased expression of Lck and cell-surface CD3 antigen. Among these changes, an increase in the expression of Lyn and a decrease in the expression of Lck and cell- surface CD3 antigen were observed only in Tax1-immortalized T cells after long-term culture. The expression level of Tax1 protein did not differ significantly between early and late passage of cells, and the cellular clonality was found to be the same by the analysis of the retroviral vector integration site and the T-cell receptor beta-chain gene rearrangement pattern. These changes in the expression of Lyn, Lck, and cell-surface CD3 antigen probably resulted from indirect effects of Tax1 that appeared after extended culture.     

Molecular characterization of human T cell leukemia virus type 1 subtypes in a group of infected individuals diagnosed in Portugal and Spain

Over the past decade, Portugal and Spain received large numbers of immigrants from HTLV-1 endemic areas. Our aim was to investigate the diversity of subtypes circulating in these two countries and the introduction of new variants. We performed a molecular analysis of HTLV-1 strains in patients diagnosed since 1998. LTR and env proviral sequences from 26 individuals were analyzed to generate phylogenetic trees along with reference HTLV-1 subtypes from several geographic origins. Epidemiological and clinical data were recorded. Most subjects were immigrants (57.7%) from South America and Africa. All isolates belonged to the cosmopolitan A subtype. Most carried the transcontinental subgroup A, but five subjects carried subgroup D and one carried subgroup C, previously unreported in Europe. HTLV strains showed separate clusters linked to the patients' geographic origin. Although subjects with HTLV-1 infection tend not to be engaged in high-risk practices, silent dissemination of a broad diversity of HTLV-1 viruses may still occur.     

CD4+ T cell surface CCR5 density as a determining factor of virus load in persons infected with human immunodeficiency virus type 1

The intensity of expression of the chemokine receptor CCR5 is involved in in vitro cell infectability by human immunodeficiency virus (HIV)-1 R5 isolates. Because CCR5 expression varies among individuals, the hypothesis that this expression could determine virus load in HIV-1-infected persons was tested. The mean number of CCR5 molecules per cell was measured on peripheral blood CD4+ T lymphocytes (CCR5 density) from HIV-1-infected, asymptomatic, nontreated adults. There was a strong correlation between HIV RNA plasma level and CCR5 density (P=.009) that was independent of cell activation and was not due to an HIV-induced CCR5 up-regulation. These data are compatible with the hypothesis that CCR5 density is a key factor governing cell infectability and in vivo virus production and explain the protective effect of the Delta32CCR5 deletion, which results in low CCR5 expression. CCR5 density might be of critical predictive value in HIV infection.     

Study of autoantibodies in patients with keratoconjunctivitis sicca infected by the human T cell lymphotropic virus type 1

Human T cell lymphotropic virus type 1 (HTLV-1) is endemic in many regions of the world, including Brazil, and has been associated to several immunological manifestations such as arthritis, uveitis, dermatitis and Sjögren’s syndrome. This study was intended to evaluate the frequency of autoantibodies in patients infected with HTLV-1 and manifesting keratoconjunctivitis sicca (KCS). HTLV-1 patients with KCS, enrolled in a reference ambulatory of the city of Salvador, were tested for autoantibodies such as antinuclear antibodies, rheumatoid factor, anti-SSA/Ro and anti-SSB/La. Two comparison groups were also included: (a) HTLV-1 patients without KCS and (b) seronegative patients with KCS. Correlation of proviral load (PVL) in HTLV-1 patients with presence or absence of KCS was also assessed. No autoantibodies were detected in HTLV-1 patients with KCS. The PVL of HTLV-1 patients was higher in patients with KCS without other clinical manifestations customarily associated to HTLV-1. In conclusion, in this study, no changes were observed in humoral immunity concerning production of certain autoantibodies in HTLV-1-infected patients with KCS, which suggests that other mechanisms may be involved in the pathogenesis of this manifestation. Additionally, PVL may be a marker of KCS development in these patients.     

Formation of IgE-binding factors by T cells of patients infected with human immunodeficiency virus type 1.

Peripheral blood mononuclear cells of 10 out of 26 patients with human immunodeficiency virus type 1 (HIV-1) released IgE-binding factors, as determined by two independent assays. The formation of the factors by the mononuclear cells was enhanced by incubation of the cells with homologous IgE. In the presence of IgE, peripheral blood mononuclear cells from 15 of the 26 patients formed a detectable amount of IgE-binding factors, whereas those of normal individuals of allergic rhinitis patients failed to do so. The major source of IgE-binding factors was the T cells of the HIV-1-infected patients. The CD8+ T cells from a HIV-1-infected patient formed IgE-binding factors upon incubation with IgE, and type II receptors for Fc epsilon were detected on both CD4+ T cells and CD8+ T cells in one of five patients studied. It was also found that culture supernatants of mononuclear cells from HIV-1-infected patients released soluble factors that induce normal human T cells to form IgE-binding factors. The results suggest that lymphocytes of some HIV-1-infected patients are activated to produce lymphokines regulating formation of IgE-binding factors.     

Abundant transcription of a cellular gene in T cells infected with human T-cell leukemia-lymphoma virus.

Human T-cell leukemia-lymphoma virus (HTLV) is a type C retrovirus associated with a subtype of mature T-cell malignancy in humans. HTLV also infects normal human cord blood mature T lymphocytes in vitro and induces a number of phenotypic changes in these cells, including their continuous growth and partial or complete independence of T-cell growth factor (TCGF). As part of our initial study designed to analyze gene(s) specifically activated by HTLV infection, we have isolated a recombinant DNA clone by differential screening of a cDNA library made from mRNA of a human T-cell lymphoma cell line producing HTLV. This cDNA identifies a single-copy gene in all human DNAs and a single mRNA species of 2.3 kilobases expressed at several hundred copies per cell in five HTLV-positive neoplastic T-cell lines. In addition, cord blood T lymphocytes infected with HTLV, but not the uninfected counterparts, express high levels of mRNA from this gene. A survey of different human hematopoietic cell types showed that this gene is expressed at low or undetectable levels (less than 10 copies) in human T, B, myeloid, or erythroid cell lines; in moderate amounts in lymphoid precursor (immature) cell lines; and in high amounts in lectin-activated mature T-cells, comparable to those of HTLV-infected T-cell lines. The precise function of this gene has not yet been determined.     

Mother-to-offspring transmission of human T cell leukemia virus type I in rabbits

We studied the mode of natural transmission of human T-cell leukemia virus type I (HTLV-I) in rabbits. Four virus-infected rabbits (2 males and 2 females) were individually mated with 4 noninfected rabbits. Two virus-infected females mated with noninfected males gave birth to 7 offspring, and 2 noninfected females mated with infected males delivered 5 offspring. Four of the seven offspring born to the virus- infected mothers seroconverted for HTLV-I when aged 6 to 13 weeks with antibody titers of 1:40 to 1:160. None of the five offspring born to the noninfected mothers became seropositive during the observation period of 6 months, however. Peripheral lymphocytes were cultured with T cell growth factor, and HTLV-I-carrying lymphoid cell lines were established from the four seroconverted rabbits. All four cell lines were of T cells positive for Ia antigens. In addition, none of five newborn rabbits killed immediately after birth to a virus-infected rabbit was infected with HTLV-I. These findings provide an experimental support for the milkborne transmission of HTLV-I from mother to child in humans and indicate that the virus is tropic for T cells in rabbits as well.     

Higher prevalence of fibromyalgia in patients infected with human T cell lymphotropic virus type I

OBJECTIVE:. Inflammatory rheumatic conditions including rheumatoid arthritis and Sj?gren's syndrome have been reported in individuals infected with human T cell lymphotropic virus type I (HTLV-I). Other chronic lymphotropic virus infections such as hepatitis C and human immunodeficiency virus are associated with fibromyalgia (FM). There are no reports about the association between HTLV-I infection and FM. We evaluated the association between FM and HTLV-I infection. METHODS: We conducted a case-control study with prevalent cases. Ex-blood donation candidates with HTLV-I infection from a blood bank cohort, and healthy blood donors as a control group, were submitted to rheumatologic evaluation to compare the prevalence of FM. The following covariables were also evaluated: other rheumatic diseases, age, sex, personal income, level of education, and depression. RESULTS: One hundred individuals with HTLV-I infection and 62 non-infected blood donors were studied. Thirty-eight (38%) HTLV-I infected individuals and 3 (4.8%) individuals from the control group presented the diagnosis of FM (OR 12.05, 95% CI 3.53-41.17). Other rheumatic diseases were also more prevalent in the infected group (37% vs 12.9%; OR 3.80, 95% CI 1.63-8.86). In multivariate analysis adjusted by the covariables, the association between HTLV-I and FM was statistically significant (OR 9.14, 95% CI 2.42-34.52). CONCLUSION: Our study shows a greater prevalence of FM in HTLV-I infected individuals, suggesting that FM may be associated with this viral infection.     

Immunological and virological status of a hemophiliac infected with human T cell lymphotropic virus type 1 and human immunodeficiency virus type 1, and results of therapy

The immunological and virological status of three hemophiliacs infected with human immunodeficiency virus type 1 (HIV-1) was monitored for 11 months. One of these patients was also infected with human T cell lymphotropic virus type 1 (HTLV-1), and HIV-1 could be isolated only from this patient among the three subjects. The doubly infected subject had the fewest T4 (helper) lymphocytes and the highest proportion of T8 lymphocytes with DR human leukocyte antigens (DR-Ag). The serum level of HIV-1 antigen increased in this patient during the observation period, and this increase was accompanied by a decrease in the proportion of DR-Ag-positive cells among the T8 lymphocytes. This patient was treated with 800 mg of zidovudine daily for 50 days. With treatment, the nonspecific clinical symptoms improved and the proportions of DR-Ag positive cells among the T8 lymphocytes decreased. Serum levels of HIV-1 antigen decreased immediately when therapy was started but later increased during therapy. In persons infected with both HTLV-1 and HIV-1, HIV-1 seems to proliferate readily.     

Establishment of an interleukin 2-dependent human T cell line from a patient with T cell chronic lymphocytic leukemia who is not infected with human T cell leukemia/lymphoma virus

We established an interleukin 2 (IL-2)-dependent human T cell line, Kit 225, from a patient with T cell chronic lymphocytic leukemia (T-CLL) with OKT3+, -T4+, -T8- phenotype. Southern blot analysis showed that Kit 225 is not infected with human T cell leukemia/lymphoma virus (HTLV) type I or II, and is probably derived from the major clone in the fresh leukemic cells. Kit 225 cells express a large amount of IL 2 receptors constitutively and their growth is absolutely dependent on IL 2. No other stimuli, such as lectins or antigens, are required for maintaining the responsiveness to IL 2. As abnormal IL 2 receptor expression was also seen originally in the fresh leukemic cells, the establishment of this cell line with IL 2 suggests that IL 2-mediated T cell proliferation is involved in the leukemogenesis of some cases of HTLV-negative T-CLL.