Differential inhibition of HIV-1 cell binding and HIV-1-induced syncytium formation by low molecular weight sulphated polysaccharides.

Dextran sulphate (MW 5000 and 8000) and a polysulphated glycosaminoglycan (MW 10,000), at concentrations that provided complete protection in a homologous infection assay, failed to block syncytium formation and the resulting cytopathic effect when MT-2 cells were mixed with H9/HIV-1 cells. These substances also had no antiviral activity when added to cells, after virus challenge, at a time when binding and entry were complete. However, a high molecular weight (500,000) dextran sulphate blocked HIV-1 infection at both stages. Thus, the gp120-CD4 interactions mediating HIV-1 binding and HIV-1-induced syncytium formation are differentially affected by this class of polyanionic substances. Furthermore, size may be a determining factor in their potential application as anti-HIV treatment.     

Increased prevalence of human T cell lymphotropic virus type 1 in patients attending a Brazilian dermatology clinic

Brazil may have the highest absolute number of individuals infected by human T cell lymphotropic virus type 1 (HTLV-1). It has been suggested that the prevalence of HTLV-1 is increased in patients with skin diseases. This study shows a higher prevalence of this infection in 1,229 patients attending a Brazilian dermatology clinic (0.7%) when compared to blood donors (0.22%). Of note, one additional patient tested positive for HTLV-2. The main skin diseases described in HTLV-1 seropositives were vitiligo (2 cases), dermatophytosis (2 cases), and leprosy (2 cases). A 23-year-old woman received a diagnosis of infectious dermatitis.     

Seronegative virus carriers in the infection of rabbits with human T lymphotropic virus type I

Six HTLV-I-transformed T cell lines were prepared from PBL of three rabbits each of B/J and Chbb:HM strains, and were inoculated into newborn rabbits of these two strains, and of their F1 hybrid. None of three B/J cell lines induced anti-HTLV-I antibody response in newborn B/J rabbits, whereas all three Chbb:HM cell lines did induce a response in newborn Chbb:HM rabbits. These B/J cell lines however could induce antibody response in adult B/J as well as newborn Chbb:HM rabbits, and a Chbb:HM cell line could induce a response in a newborn B/J rabbit. Similar unresponsiveness was observed in (B/J x Chbb:HM)F1 hybrids neonatally inoculated with B/J cells. Unresponsiveness was abrogated by reinoculation of some but not other cell lines. Viral antigen-positive cell lines harboring HTLV-I provirus genomes were established from such seronegative B/J and F1 rabbits. Simultaneous inoculation of HTLV-I-transformed cells and SPV resulted in the induction of papilloma and antibody against SPV, but not antibody against HTLV-I. The present findings thus reveal that neonatal infection of HTLV-I could result in immunological tolerance to the virus antigens, thereby leading to a persistent infection without antibody induction.     

High human T cell lymphotropic virus type 1 (HTLV-1)-specific precursor cytotoxic T lymphocyte frequencies in patients with HTLV-1-associated neurological disease

The frequencies of human T cell lymphotropic virus type 1 (HTLV-1)- specific CD8+ precursor cytotoxic T lymphocytes (pCTL) were quantitated from lymphocytes obtained from the peripheral blood and cerebrospinal fluid (CSF) of infected individuals with and without HTLV-1-associated neurological disease. An estimate of the pCTL was obtained by separating CD8+ cells, plating these cells in limiting dilution, and testing wells for HTLV-1 specific lysis. Targets consisted of autologous lymphoblastoid cell lines (LCL) infected with vaccinia constructs expressing HTLV-1 gene products or LCL pulsed with HTLV-1 synthetic peptides. In patients with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), the frequency of HTLV-1 p40X-specific pCTL was at least 40-280-fold higher than in asymptomatic HTLV-1-infected individuals. All HAM/TSP patients (five of five) predominantly recognized HTLV-1 products encoded within the pX region. Lower pCTL to env were demonstrated in three patients, and only one of five HAM/TSP patients had pCTL to gag. A synthetic peptide corresponding to the tax region of HTLV-1 (peptide 11-19, amino acid sequence LLFGYPVYV) was recognized in association with human histocompatibility leukocyte antigen (HLA)-A2 in two HLA-A2 HAM/TSP patients with a high CD8+ pCTL frequency of 1/325 and 1/265, respectively. A second immunodominant region of HTLV-1 tax (peptide 90- 55, amino acid sequence VPYKRIEEL) was identified to be restricted by HLA-B14 in two HLA-B14 HAM/TSP patients with a CD8+ pCTL frequency of 1/640 and 1/1,125, respectively. Lymphocytes from the CSF of a patient with HAM/TSP also showed a pCTL frequency against p40X of similar magnitude to that demonstrated from peripheral blood lymphocytes (PBL). The HLA-A2-mediated CSF pCTL activity to the immunodominant tax- specific peptide 11-19 was also comparable to pCTL from PBL. These results indicate that an extremely high pCTL frequency to HTLV-1 tax- encoded peptides may be related to pathogenesis of myeloneuropathy associated with HTLV-1.     

Immunopathological mechanisms of human T cell lymphotropic virus type 1 (HTLV-I) uveitis. Detection of HTLV-I-infected T cells in the eye and their constitutive cytokine production.

The immunopathology of human T cell lymphotropic virus type 1 (HTLV-I) uveitis was addressed by using T cell clones (TCC) established from the intraocular fluid of patients with HTLV-I uveitis. Proviral DNA of HTLV-I was identified in 55 out of 94 (59%) or 13 out of 36 (36%) TCC from the ocular fluid or the peripheral blood of these patients, respectively. Most of HTLV-I-infected TCC had a CD3+ CD4+ CD8- phenotype. HTLV-I infection on TCC was confirmed by analysis of the viral mRNA, nucleotide sequence, virus-associated proteins, and virus particles. HTLV-I-infected TCC, but not HTLV-I negative TCC, constitutively produced high amounts of IL-6 (1,336 +/- 1,050 pg/ml) and TNF-alpha (289 +/- 237 pg/ml) in the absence of any stimuli. HTLV-I-infected TCC from the ocular lesion also constitutively produced high amounts of IL-1 alpha (12,699 pg/ml), IL-2 (61 pg/ml), IL-3 (428 pg/ml), IL-8 (1,268 pg/ml), IL-10 (28 pg/ml), IFN-gamma (5,095 pg/ml), and GM-CSF (2,886 pg/ml). Hydrocortisone, a drug effective in vivo for the treatment of HTLV-I uveitis, severely depressed cytokine production in vitro in most cases. In summary, the results demonstrated direct evidence of HTLV-I infection of the eye and suggest that cytokines produced by HTLV-I-infected T cells are responsible for the intraocular inflammation in patients with HTLV-I uveitis.     

Bile salt-stimulated lipase from human milk binds DC-SIGN and inhibits human immunodeficiency virus type 1 transfer to CD4+ T cells

A wide range of pathogens, including human immunodeficiency virus type 1 (HIV-1), hepatitis C virus, Ebola virus, cytomegalovirus, dengue virus, Mycobacterium, Leishmania, and Helicobacter pylori, can interact with dendritic cell (DC)-specific ICAM3-grabbing nonintegrin (DC-SIGN), expressed on DCs and a subset of B cells. More specifically, the interaction of the gp120 envelope protein of HIV-1 with DC-SIGN can facilitate the transfer of virus to CD4+ T lymphocytes in trans and enhance infection. We have previously demonstrated that a multimeric LeX component in human milk binds to DC-SIGN, preventing HIV-1 from interacting with this receptor. Biochemical analysis reveals that the compound is heat resistant, trypsin sensitive, and larger than 100 kDa, indicating a specific glycoprotein as the inhibitory compound. By testing human milk from three different mothers, we found the levels of DC-SIGN binding and viral inhibition to vary between samples. Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western blotting, and matrix-assisted laser desorption ionization analysis, we identified bile salt-stimulated lipase (BSSL), a Lewis X (LeX)-containing glycoprotein found in human milk, to be the major variant protein between the samples. BSSL isolated from human milk bound to DC-SIGN and inhibited the transfer of HIV-1 to CD4+ T lymphocytes. Two BSSL isoforms isolated from the same human milk sample showed differences in DC-SIGN binding, illustrating that alterations in the BSSL forms explain the differences observed. These results indicate that variations in BSSL lead to alterations in LeX expression by the protein, which subsequently alters the DC-SIGN binding capacity and the inhibitory effect on HIV-1 transfer. Identifying the specific molecular interaction between the different forms may aid in the future design of antimicrobial agents.     

Infection of human synovial cells by human T cell lymphotropic virus type I. Proliferation and granulocyte/macrophage colony-stimulating factor production by synovial cells.

The present study was performed to clarify the relationship between human T cell lymphotropic virus type I (HTLV-I) infection and chronic inflammatory arthropathy. To determine the ability of HTLV-I to infect synovial cells and the effect on synovial cell proliferation, synovial cells were cocultured with the HTLV-I-producing T cell lines (MT-2 or HCT-1). After coculture with HTLV-I-infected T cells, the synovial cells expressed HTLV-I-specific core antigens, and HTLV-I proviral DNA was detected from the synovial cells by polymerase chain reaction. These cocultured synovial cells with HTLV-I-infected T cells proliferated more actively than the synovial cells cocultured with uninfected T cells. This stimulatory effect of HTLV-I-infected T cells on synovial cell proliferation seems necessary to contact each other. After being cocultured with MT-2 cells, synovial cells proliferated more actively than control cells even after several passages. Furthermore, HTLV-I-infected synovial cells produced significant amounts of granulocyte/macrophage colony-stimulating factor. These results suggest that HTLV-I can infect synovial cells, resulting their active proliferation and may be involved in the pathogenesis of proliferative synovitis similar to that found in rheumatoid arthritis.     

Pharmacological inhibition of in vitro infectivity of human T lymphotropic virus type I.

Human T lymphotropic virus type I (HTLV-I) is an exogenous RNA tumor virus etiologically linked to adult T cell leukemia and related diseases. In this paper, we describe that two 2',3'-dideoxynucleoside analogues, erythro 3'-azido-2',3'-dideoxythymidine (also called azidothymidine) and 2',3'-dideoxycytidine can inhibit the infectivity of HTLV-I against helper/inducer T cells in vitro. Both 2',3'-dideoxynucleoside analogues inhibited the overgrowth of target T cells, which was a consequence of virally mediated transformation, when they were exposed to the virus and cultured with the compounds. A profound decrease in the expression of HTLV-I gag-proteins was also observed. Moreover, we observed that the amount of proviral DNA detected in cellular DNA from the target T cells was substantially reduced when the cells were protected by the compounds against the virus and that at certain concentrations of the compounds the synthesis of viral DNA was completely suppressed. These results may be of value in developing a new pharmacological strategy for preventing the replication and possibly blocking the transmission of HTLV-I and related retroviruses in human beings.     

Plasma exchange for the treatment of human T-cell lymphotropic virus type 1 associated myelopathy.

A 55-year-old man was admitted to our hospital because of myelopathy. He had a history of chronic renal failure due to polycystic kidney disease at the age of 39, being treated by hemodialysis for 9 years with several blood transfusions for the treatment of renal anemia. After cadaver renal transplantation at the age of 48, he discontinued hemodialysis. At 50 years of age, he had pulmonary tuberculosis and tuberculous arthritis of the left elbow joint. He has experienced difficulty in walking since he was 48 years old, with mild dysuria. Gait disturbance gradually aggravated after that, and urinary retention was observed. When he was 55 years old, being human T-cell lymphotropic virus type-1 (HTLV-1)-positive in the serum and cerebrospinal fluid, he was diagnosed as having HTLV-1-associated myelopathy (HAM). As active steroid therapy was unapplicable because of the history of pulmonary tuberculosis and immunosuppression for transplanted kidney, a series of plasma exchanges (PE) was performed with fresh frozen plasma as a replacement fluid. After PE, dyskinesia of the left leg and dysuria subjectively and objectively improved. These results suggest that PE seems to be one of the therapeutic tools for the treatment of HAM.     

Nonspecific interstitial pneumonia pattern as pulmonary involvement in human T-cell lymphotropic virus type 1 carriers

It is well established that diffuse interstitial shadows are observed in human T-cell lymphotropic virus type 1 (HTLV-1) carriers. However, the pathological pattern of nonspecific interstitial pneumonia (NSIP) has rarely been reported. Here, we describe the clinical features of four patients with histologically proven NSIP and HTLV-1 infection. The patients, one woman and three men, had a median age of 59.5 years. High-resolution computed tomography of the lungs was performed in all patients, and no apparent honeycomb formations were detected. The present study demonstrates that the NSIP pattern is a significant pathological classification of interstitial pneumonia associated with HTLV-1 carriers.     

Transactivation of the transforming growth factor beta 1 (TGF-beta 1) gene by human T lymphotropic virus type 1 tax: a potential mechanism for the increased production of TGF-beta 1 in adult T cell leukemia

We examined the effect of the human T lymphotropic virus type 1 (HTLV-I) Tax gene product on the human transforming growth factor beta 1 (TGF-beta 1) promoter. Transfection of deleted constructs of the TGF-beta 1 promoter revealed regions homologous with AP-1 binding sites that were required for Tax-induced transactivation of the TGF-beta 1 promoter. In addition, we examined the expression and secretion of TGF-beta in fresh leukemic cells isolated from patients with adult T cell leukemia (ATL) and in HTLV-1-infected T cell lines. We report that fresh leukemic cells from ATL patients constitutively produce high levels of TGF-beta 1 mRNA and secrete TGF-beta 1 but not TGF-beta 2 into the culture medium. In addition, long-term ATL cell lines expressed significant amounts of TGF-beta 1 mRNA as well as detectable levels of TGF-beta 1 protein. These results suggest a role for Tax in the upregulation of TGF-beta 1 in HTLV-I-infected cells.     

Effect of lamivudine on transmission of human T-cell lymphotropic virus type 1 to adult peripheral blood mononuclear cells in vitro

The effects of lamivudine (3TC) on in vitro infection of peripheral blood mononuclear cells (PBMC) from healthy donors with human T-cell lymphotropic virus type 1 (HTLV-1) were investigated. Direct measures of viral replication (viral DNA, RNA, and protein) all gave similar, very high 50% inhibitory concentrations in comparison with those previously reported for zidovudine. Nevertheless, 3TC inhibited HTLV-1-driven long-term growth of infected PBMC in vitro at concentrations (6.25 micro M) which had poor or no direct antiviral effects, suggesting that another mechanism may be playing a role.     

Inhibition of cell-to-cell transmission of human T-cell lymphotropic virus type 1 in vitro by carbohydrate-binding agents

Peripheral blood mononuclear cells (PBMCs) from healthy individuals can be infected by human T-lymphotropic virus type 1 (HTLV-1) upon cocultivation of the PBMCs with irradiated HTLV-1-transformed human MT-2 cells. This model system closely mimics HTLV-1 transmission through cell-to-cell contact. Carbohydrate-binding agents (CBAs) such as the α(1,3)/α(1,6)mannose-specific Hippeastrum hybrid agglutinin and the GlcNAc-specific Urtica dioica agglutinin, and also the small, nonpeptidic α(1,2)-mannose-specific antibiotic pradimicin A, were able to efficiently prevent cell-to-cell HTLV-1 transmission at nontoxic concentrations, as evidenced by the lack of appearance of virus-specific mRNA and of the viral protein Tax in the acceptor cells. Consistently, antivirally active doses of CBAs fully prevented HTLV-1-induced stimulation of PBMC growth. The inhibitory effects of CBAs on HTLV-1 transmission were also evident when HTLV-1-infected C5MJ cells were used in place of MT-2 cells as a virus donor cell line. The anti-HTLV-1 properties of the CBAs highlight the importance of the envelope glycans in events underlying HTLV-1 passage from cell to cell and indicate that CBAs should be further investigated for their potential to prevent HTLV-1 infection, including mother-to-child virus transmission by cell-to-cell contact through breast milk feeding.     

Virucidal effect of myeloperoxidase on human immunodeficiency virus type 1-infected T cells.

Myeloperoxidase is virucidal to human immunodeficiency virus type 1 (HIV-1) in the persistently infected CEM human T-cell line or in acutely infected human peripheral blood mononuclear cells, as judged by viral infectivity and P24 radioimmunoassay. HIV-1 was specifically inactivated by low doses of the human myeloperoxidase (1.4 to 14.3 mU/ml) and the cells were spared. A higher enzyme concentration (143 mU/m) was cytotoxic, but uninfected CEM cells and normal lymphocytes were resistant to > or = 143 mU of myeloperoxidase per ml. The enzyme was virucidal with the Cl- present in medium and did not require exogenous H2O2. Catalase, an antioxidant enzyme, partially inhibited the virucidal effect of myeloperoxidase. Hence, the H2O2 probably came from the HIV-infected cells themselves. These in vitro findings indicate that the myeloperoxidase system is capable of inactivating HIV-1 of infected cells.