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Biomedical subjects

R C Gallo

Publications and source records attributed to R C Gallo.

At least 343 records · Page 19Linked to original sources
PubMed1986

Serological characterization of human T-cell leukemia (lymphotropic) virus, type I (HTLV-I) small envelope protein.

Murine monoclonal antibodies were developed against the protein products produced by murine C127 cells which had been transfected with a recombinant plasmid clone containing the human T-cell leukemia (lymphotropic) virus type I (HTLV-I) proviral DNA coding regions for part of env, px, and the 3' LTR. Four antibodies with different binding patterns were obtained. One of these antibodies, F1.6, reacted against HTLV-I infected cells but not against noninfected cell lines. This antibody also reacted with sucrose-gradient purified HTLV-I and -II particles with preferential binding against the HTLV-I preparation. The F1.6 antibody bound to two proteins of approximately 21 and 43 kDa in gradient purified HTLV-I preparations, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blots, and to a 43-kDa protein in cell lysates of HTLV-I infected cell lines; the F1.6 antibody did not bind significantly to any HTLV-II proteins in western blots. The three other antibodies F1.1, F1.2, and F1.5, recognized the same size proteins, 21 and 43 kDa in the gradient purified viral preparations of HTLV-I and in the case of the F1.2 antibody, the same size proteins in purified virus preparation of HTLV-II and -III. The F1.2 and F1.5 antibodies bound not only to purified HTLV particles but also to a variety of cellular proteins in HTLV-I infected and noninfected cells suggesting that they recognized epitopes which were shared between HTLV proteins and normal cells. The identity of the 21-kDa viral protein is most likely that of the small envelope glycoprotein. The identity of the larger protein is undetermined.

Antibodies, Monoclonal↗
PubMed1986

Characterization of highly immunogenic p66/p51 as the reverse transcriptase of HTLV-III/LAV.

Approximately 80 percent of all human sera that react with antigens of HTLV-III, the etiologic agent of the acquired immune deficiency syndrome (AIDS), recognize protein bands at 66 and 51 kilodaltons. A mouse hybridoma was produced that was specific to these proteins. Repeated cloning of the hybridoma did not separate the two reactivities. The p66/p51 was purified from HTLV-III lysates by immunoaffinity chromatography and subjected to NH2-terminal Edman degradation. Single amino acid residues were obtained in 17 successive degradation cycles. The sequence determined was a perfect translation of the nucleotide sequence of a portion of the HTLV-III pol gene. The purified p66/51 had reverse transcriptase activity and the monoclonal immunoglobulin G specifically removed the enzyme activity from crude viral extract as well as purified enzyme.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Long-term cultures of HTLV-III--infected T cells: a model of cytopathology of T-cell depletion in AIDS.

Long-term cultures were established of HTLV-III-infected T4 cells from patients with the acquired immune deficiency syndrome (AIDS) and of T4 cells from normal donors after infection of the cells in vitro. By initially reducing the number of cells per milliliter of culture medium it was possible to grow the infected cells for 50 to 60 days. As with uninfected T cells, immunologic activation of the HTLV-III-infected cells with phytohemagglutinin led to patterns of gene expression typical of T-cell differentiation, such as production of interleukin-2 and expression of interleukin-2 receptors, but in the infected cells immunologic activation also led to expression of HTLV-III, which was followed by cell death. The results revealed a cytopathogenic mechanism that may account for T4 cell depletion in AIDS patients and suggest how repeated antigenic stimulation by infectious agents, such as malaria in Africa, or by allogeneic blood or semen, may be important determinants of the latency period in AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Hydrocortisone and some other hormones enhance the expression of HTLV-III.

The ability to productively infect fresh normal human peripheral blood mononuclear leukocytes with HTLV-III was improved by supplementing cell culture medium with either the gonadal steroid, chorionic gonadotropin, or insulin, and more substantially with the adrenocortical steroid, hydrocortisone. Several other sex hormones and another corticosteroid, dexamethasone, had no significant effect. In addition, the isolation of HTLV-III from lymphocytes established in culture from patients with the acquired immunodeficiency syndrome (AIDS), AIDS-related complex (ARC), and healthy, at-risk donors was greatly facilitated by the inclusion of hydrocortisone in cell culture media. In 13/20 primary cell cultures tested from AIDS and ARC patients from whom virus was isolated, the amount of virus produced was elevated from low to easily detectable levels in those containing hydrocortisone. In 3/20 specimens tested, virus was detected and isolated from cell cultures supplemented with hydrocortisone but was undetectable in those lacking the hormone. These experiments demonstrate that hydrocortisone, a readily available, inexpensive supplement to cell culture media, can facilitate the detection and isolation of HTLV-III. These studies, furthermore, suggest a role for corticosteroids and possibly gonadal steroids in the modulation of virus expression and/or release and suggest that the viral inductive capacity of these and other compounds should be considered as they are evaluated for clinical use.

Acquired Immunodeficiency Syndrome↗
PubMed1986

HTLV: the family of human T-lymphotropic retroviruses and their role in leukemia and AIDS.

Since 1980 four members of a new retrovirus family called the human T-lymphotropic viruses (HTLV-I to -IV) have been discovered and to a large extent characterised. Important common features of these viruses are: transmission by sexual contact or blood, tropism for the T4-lymphocyte and the effects of a viral transactivating gene (tat). They differ in their pathogenic effects, HTLV-I and -II being associated with lymphoproliferative malignancies, while HTLV-III is cytopathic and associated with immunosuppression. HTLV-IV is, apparently, not directly highly pathogenic for man. An African origin for this family of viruses is suggested by recent isolations of similar (STLV-I and -III) viruses in Old World primates. Prospects for the possible development of a cross-reactive vaccine have increased since the demonstration of highly conserved DNA sequences in the envelope region of several divergent HTLV-III strains.

Acquired Immunodeficiency Syndrome↗
PubMed1986

HTLV-III in the tears of AIDS patients.

The human T-cell leukemia/lymphotropic virus type III (HTLV-III), the causative agent of the acquired immunodeficiency syndrome (AIDS), has been isolated from the tears of five AIDS patients. When combined with data from our previous study, 5 of 16 samples from patients with AIDS or AIDS-related complex (ARC) showed positive isolates for HTLV-III from the tears. Normal control tears were negative for HTLV-III. Based upon these findings, the Centers for Disease Control (CDC) has issued precautions to prevent any possible spread of the virus by this route. Although there is no evidence to suggest transmission of HTLV-III by contact with the tears, until more is known about the possible transmissibility and infectious dose of this virus, such precautions should be taken during ophthalmic examination.

AIDS-Related Complex↗
PubMed1986

Occurrence of human T cell lymphotropic virus (type I) antibodies in cutaneous T cell lymphoma.

Of 315 patients from Scandinavia and West Germany with cutaneous T cell lymphoma, thirty-six (11.4%) had specific antibodies reactive against human T cell lymphotropic virus type I (HTLV-I). Among the HTLV-I antibody-positive patients, one had Sézary syndrome; five, mycosis fungoides, plaque stage; sixteen, mycosis fungoides, plaque stage with nondiagnostic histologic features; and three, lymphomatoid papulosis. All the patients from the Copenhagen area had several samples taken during the course of their disease, but the HTLV-I antibody titer was unaltered independent of the clinical stage the individual patient had at the time of the study. Eighty-three patients with non-Hodgkin's lymphoma were tested for HTLV-I antibodies, and all except two showed negative results. The finding of specific antibodies reactive against HTLV-I in cutaneous T cell lymphoma suggests that a retrovirus related to HTLV-I plays an important role in the pathogenesis of cutaneous T cell lymphoma.

Antibodies, Viral↗
PubMed1986

Human T-cell lymphotropic virus type III shares sequence homology with a family of pathogenic lentiviruses.

The etiologic agent of the acquired immune deficiency syndrome, human T-cell lymphotropic virus type III (HTLV-III), has recently been shown to morphologically resemble and share sequence homology with visna virus, a pathogenic lentivirus. Molecular hybridization, heteroduplex mapping, and DNA sequence analyses were used to compare HTLV-III to other lentiviruses of domestic animals, including visna, caprine arthritis encephalitis, and equine infectious anemia viruses. Hybridization results showed that a substantial amount of sequence homology exists between each of these viruses and HTLV-III. In addition, a closer relationship was found between visna and caprine arthritis encephalitis viruses than for any of the other lentiviruses studied. These results, along with nucleotide and amino acid sequence comparisons, have been used in a comprehensive effort to derive a systematic relationship for lentiviruses and to provide further evidence for classifying HTLV-III with the Lentivirinae subfamily of retroviruses. This relationship predicts that similarities in biology and disease process can be expected between HTLV-III and other Lentivirinae members.

Cloning, Molecular↗
PubMed1986

Differential response to the cytopathic effects of human T-cell lymphotropic virus type III (HTLV-III) superinfection in T4+ (helper) and T8+ (suppressor) T-cell clones transformed by HTLV-I.

We isolated six human T-cell lymphotropic virus type I (HTLV-I)-transformed T-cell clones carrying the phenotypic markers of helper and suppressor T cells. Five of the transformed T-cell clones produced infectious HTLV-I, but one (clone 55) contained a defective provirus and was therefore not competent for viral replication. To test whether there is interference between HTLV-I and the cytopathic virus HTLV-III in infection and/or their biological effects, we superinfected these T-cell clones with HTLV-III. The recipient cells that we used displayed either the OKT4 or the OKT8 membrane antigens (helper or suppressor phenotype, respectively). The superinfection was successful in all cases, regardless of phenotype of the recipient cells and status of viral production. Both HTLV-III and HTLV-I were expressed by the infected cell lines containing complete HTLV-I proviruses, as demonstrated by electron microscopy and immunofluorescence. However, only HTLV-III in the virus mixture obtained from the culture supernatants was transmitted to the human neoplastic T-cell line H9. The nonproducer clone 55 did not express HTLV-I upon superinfection with HTLV-III. HTLV-III exerted its cytopathic effect on all but one of the superinfected T-cell clones 15-20 days after infection. The exception, clone 67, is also the only cell clone that expresses the phenotypic marker of suppressor T lymphocytes (OKT8); the other clones carry the OKT4 antigen, correlated with helper functions. The virus released from the superinfected clone 67 is cytopathic for fresh peripheral and umbilical-cord blood lymphocytes, suggesting that cellular factors, rather than a genetic change in the virus, may be responsible for the lack of cytopathic effect of HTLV-III on the suppressor T-cell clone 67.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1986

Stimulatory and inhibitory influences of human immunodeficiency virus on normal B lymphocytes.

B-lymphocyte dysfunction is a characteristic feature of the acquired immunodeficiency syndrome (AIDS) and of the AIDS-related complex. The aim of the present study was to further examine the influences exercised by the human immunodeficiency virus (HIV; formerly called human T-lymphotropic virus type III or lymphadenopathy-associated virus, HTLV-III/LAV) on normal human B lymphocytes. An unfractionated protein preparation, made from HIV purified by density gradient centrifugation, was previously shown to induce differentiation of normal human B lymphocytes into immunoglobulin-secreting cells. In the present analyses, this B-lymphocyte response peaked on day 6 or 7 after culture initiation and was found to be independent of the requirement for monocytes but to require T cells. Responses could also be elicited in cultures of purified B cells by the addition of T cells that had been exposed to HIV antigen. Inhibitors of protein synthesis (puromycin and cycloheximide) abrogated the responses. In contrast to its stimulatory effects, the same virus preparation was previously shown to inhibit polyclonal responses that are normally elicited in peripheral blood lymphocyte cultures by a T-dependent stimulus (pokeweed mitogen) and T-independent stimulus (Epstein-Barr virus). The present studies suggest that the inhibitory effects of the HIV antigen studied herein are targeted primarily at the B lymphocytes. The role of T lymphocytes in the HIV antigen-mediated inhibitory effects, although demonstrated, could not be conclusively established as an essential pathway. These findings elucidate mechanisms by which components of HIV exert stimulatory as well as inhibitory effects on human B lymphocytes and thereby lead to the dysfunction of these cells in HIV infection.

Antibody-Producing Cells↗
PubMed1986

Restricted neutralization of divergent human T-lymphotropic virus type III isolates by antibodies to the major envelope glycoprotein.

By analogy to other retroviruses, the major envelope glycoprotein, gp120, of human T-lymphotropic virus type III (HTLV-III) is a probable target for neutralizing antibody. This antigen has been purified from H9 cells chronically infected with the HTLV-IIIB prototype strain. Several goats immunized with the gp120 produced antibodies that neutralized infection of H9 cells by the homologous virus isolate. These same sera failed to neutralize the divergent HTLV-IIIRF isolate. Individuals infected with HTLV-III commonly develop antibodies to gp120 that could be isolated by using the gp120 antigen coupled to an immunoadsorbent resin. The antibody fraction that bound tightly to such a resin was found to neutralize the IIIB but not the RF isolate in a similar fashion as the goat anti-gp120 sera. However, the nonbinding fraction (effluent) from the resin also contained neutralizing activity that was able to block infection by both virus isolates with similar efficacy. Human antibodies to the other virus envelope gene product, the transmembrane gp41, were also affinity purified by utilizing the recombinant peptide 121, but these failed to influence infection by either virus isolate.

Antibodies, Viral↗
PubMed1986

Detection of lymphocytes expressing human T-lymphotropic virus type III in lymph nodes and peripheral blood from infected individuals by in situ hybridization.

By using in situ hybridization methodology, we have directly examined primary lymph node and peripheral blood from patients with acquired immunodeficiency syndrome (AIDS) and AIDS-related complex for the presence of human T-lymphotropic virus type III (HTLV-III) viral RNA. Mononuclear cell preparations were hybridized with a 35S-labeled HTLV-III-specific RNA probe and exposed to autoradiographic emulsion for 2 days. HTLV-III-infected cells expressing viral RNA were detected in approximately 86% (6/7) of lymph node and 50% (7/14) of peripheral blood samples studied. However, in all patient samples examined, labeled cells were observed at very low frequency (less than 0.01% of total mononuclear cells). The HTLV-III-infected cells exhibited morphological characteristics consistent with that of lymphocytes and expressed viral RNA at relatively low abundance (20-300 copies per cell). These results demonstrate that HTLV-III expression in lymph node and peripheral blood is very low in vivo. Furthermore, the lymph node hyperplasia observed in HTLV-III-associated lymphadenopathy is not directly due to proliferation of HTLV-III-infected lymphocytes.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Three novel genes of human T-lymphotropic virus type III: immune reactivity of their products with sera from acquired immune deficiency syndrome patients.

Human T-lymphotropic virus type III or lymphoadenopathy associated virus (HTLV-III/LAV) is the cause of acquired immune deficiency syndrome (AIDS). In addition to the conventional retroviral genes involved in virus replication, namely, gag, pol, and env genes, DNA sequence analysis of HTLV-III genome predicted two additional open reading frames termed by us short open reading frame (sor) and 3' open reading frame (3' orf). Furthermore, functional analysis revealed another gene with transactivating function, termed tat. We have now structurally identified and functionally characterized these HTLV-III specific genes by way of cDNA cloning. DNA sequence analysis of the clones shows that the tat and 3' orf genes contain three exons and their transcription into functional mRNA involves two splicing events and that the sor gene contains at least two exons. In vitro transcription and translation of the cloned spliced sequences show that the sor, tat, and 3' orf genes code for polypeptides with apparent mobility of 24-25 kDa, 14-15 kDa, and 26-28 kDa, respectively. All three polypeptides are immune reactive and are immunogenic in the natural host. The results demonstrate that the three extra open reading frames of HTLV-III, two of which are unique to HTLV-III, are in fact genes that function in vivo and further allow the identification of three new and previously unrecognized HTLV-III antigens with differential immunogenicity in individuals with acquired immune deficiency syndrome and related disorders.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Antibodies to human T-lymphotropic virus type III and development of the acquired immunodeficiency syndrome in homosexual men presenting with immune thrombocytopenia.

In 35 homosexual men with isolated thrombocytopenia at initial presentation, who were evaluated and treated between 1982 and 1984, hematologic studies showed immune destruction. In contrast to findings in other autoimmune conditions, T-lymphocyte subsets in these patients were reversed, with a mean helper to suppressor ratio of 0.4 and with an absolute depletion of helper cells to 390/mm3. An enzyme-linked immunosorbent assay detected antibodies to human T-lymphotropic virus type III in 21 of 25 patients tested; Western blot analysis confirmed seropositivity in the other 4 patients, who had borderline findings. Although 19 of 24 patients treated with steroids responded, only 2 achieved sustained normal platelet counts. Ten of fifteen patients who had splenectomy achieved remissions. Three patients treated with steroids or splenectomy developed diagnoses compatible with the acquired immunodeficiency syndrome 16 to 34 months after their initial presentation with thrombocytopenia. These findings indicate that immune thrombocytopenia is part of the clinical spectrum of the acquired immunodeficiency syndrome.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Long-term seropositivity for human T-lymphotropic virus type III in homosexual men without the acquired immunodeficiency syndrome: development of immunologic and clinical abnormalities. A longitudinal study.

The long-term effects of seropositivity for human T-lymphotropic virus type III (HTLV-III) on T-lymphocyte subsets and health status were evaluated in longitudinal studies of 250 initially healthy homosexual men. The relative risk of having an inverted T-lymphocyte helper-to-suppressor ratio rose from 14.3-fold among short-term seropositive subjects (less than 19 months) to 46.9-fold among long-term seropositive subjects (greater than 29 months) in comparison with the risk among seronegative subjects. Overall, 91.7% of long-term seropositive men had inverted ratios, compared with 12.9% of seronegative men. None of the seropositive men who developed an inverted ratio later reestablished a normal ratio. Both decreased T-helper cell number and percentage (p = 0.003) and increased T-suppressor cell number and percentage (p = 0.03) were significantly correlated with duration of seropositivity. Among seropositive persons, lymphadenopathy was a highly significant short-term as well as long-term consequence, whereas diarrhea, oral thrush, and herpes zoster were correlated with long-term seropositivity. Overall, 50% of long-term seropositive men compared with 16% of seronegative men developed at least one of five clinical symptoms (p less than 0.003). We conclude that a high proportion of persons infected with HTLV-III will develop measurable immunologic and clinical abnormalities.

Antibodies, Viral↗