Search PubMed⌕ Search

Biomedical subjects

S Z Salahuddin

Publications and source records attributed to S Z Salahuddin.

At least 37 records · Page 2Linked to original sources
PubMed1989

Productive dual infection of human CD4+ T lymphocytes by HIV-1 and HHV-6.

Although infection by HIV-1 has been implicated as the primary cause of AIDS and related disorders, cofactorial mechanisms may be involved in the pathogenesis of the disease. For example, several viruses commonly detected in AIDS patients and capable of transactivating the long terminal repeat of HIV-1, such as herpesviruses, papovaviruses, adenoviruses and HTLV-I have been suggested as potential cofactors. Another candidate is human herpesvirus-6 (HHV-6, originally designated human B-lymphotropic virus), which has not only been identified in most patients with AIDS by virus isolation, DNA amplification techniques and serological analysis, but is also predominantly tropic and cytopathic in vitro for CD4+ T lymphocytes. Here we demonstrate that HHV-6 and HIV-1 can productively co-infect individual human CD4+ T lymphocytes, resulting in accelerated HIV-1 expression and cellular death. We also present evidence that HHV-6 transactivates the HIV-1 long terminal repeat (LTR). These observations indicate that HHV-6 might contribute directly or indirectly to the depletion of CD4+ T cells in AIDS.

Cells, Cultured↗
PubMed1989

AIDS-Kaposi's sarcoma-derived cells express cytokines with autocrine and paracrine growth effects.

When grown in vitro, cells from Kaposi's sarcoma lesions of AIDS patients (AIDS-KS cells) constitutively release several growth promoting activities. When inoculated into nude mice, the AIDS-KS cells induce a KS-like lesion of mouse origin. Here it is shown that the AIDS-KS cells express messenger RNA for a complex mixture of cytokines that correlate with several of the biological activities of these cells. Basic fibroblast growth factor, which is a potent angiogenic factor, and interleukin-1 messenger RNAs are expressed at very high levels and seem to account for a large proportion of the activities, since their corresponding proteins are released in biologically active form into the culture media where they induce autocrine and paracrine growth effects.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Demonstration of the human herpesvirus 6-induced DNA polymerase and DNase.

Infection of HSB-2 cells with human herpesvirus 6 (HHV6) results in an approximately 51-fold increase in the level of DNA polymerase activity and a 4.44-fold increase in the level of DNase activity when compared to mock-infected cells. There was no increase in thymidine kinase, uracil-DNA glycosylase, or deoxyuridine triphosphate nucleotidohydrolase activities in the infected cells. The HHV6-induced DNase and DNA polymerase activities could be distinguished from their normal cellular counterparts on the basis of immunological specificities and in the case of DNA polymerase based upon differences in electrophoretic migration. Serological studies also demonstrated reactivity of the antisera not only for HHV6 but also for Epstein-Barr virus.

Cell Line↗
PubMed1989

Viral genomes in lymphomas of patients with Sjögren's syndrome.

The recent isolation of a new member of the herpes virus family (Human Herpes Virus-6, HHV-6) from patients with lymphoproliferative diseases prompted us to examine biopsies from six patients with primary Sjögren's Syndrome (SS) who developed non-Hodgkin's lymphoma. Five SS patients developed B-cell lymphoma and one developed a T-cell lymphoma based on immunoglobulin and T-cell antigen receptor (TCAR) gene rearrangements. In two SS patients with B-cell lymphomas, viral DNAs were detected, including: (a) Epstein-Barr Virus (EBV) DNA that exhibited an unusual pattern of restriction fragment length polymorphisms (RFLP) of the Bam M viral DNA segment; and (b) HHV-6 DNA in a second SS patient's lymphoma, with an RFLP similar to recent viral isolates from patients with other lymphoproliferative diseases. Viral DNA was not detected in the other four SS lymphoma biopsies. Also, all six biopsies were examined for presence of other viral DNAs (including CMV, HTLV, HIV and adenovirus) and were negative. Antibody titers to EBV-associated early-diffuse-antigen (EA-D), as assessed by ELISA method, and antibody titers against HHV-6, as detected by immunofluorescence and radio-immunoprecipitation assays, were markedly elevated in several SS patients with lymphoma and pseudolymphoma. These results suggest a potential role of EBV or HHV-6 in the neoplastic transformation that occurs with increased frequency in SS patients.

Antigens, Viral↗
PubMed1989

AIDS-associated Kaposi's sarcoma: a molecular model for its pathogenesis.

Kaposi's sarcoma is a mesenchymal tumor that is frequently observed in AIDS patients. Although the tumor is clearly associated with HIV-1 infection, little is known about the molecular events underlying its pathogenesis. Here we consider the potential roles of specific cytokines and the virally encoded tat product in inducing the tumor.

Acquired Immunodeficiency Syndrome↗
PubMed1989

ELISA HIV testing and viral culture in the screening of corneal tissue for transplant from medical examiner cases.

The spread of AIDS and its association with a retrovirus, commonly called T-lymphotropic virus type III (HIV) has produced great concern among those involved in transplantation about the possibility for transmission of this disease through tissue and organ transplant. Isolation of the virus from conjunctiva and tears further heightened this concern for corneal transplants. This review of medical examiner (ME) cases, a population in which high numbers of transplant corneas are retrieved, has revealed positive serologic tests for HIV in serum from 5 cases in 205 screens. These represent potential donors based on other standard medical criteria available at the time of collection. This tissue was also submitted for viral culture, and virus was recovered from the corneal tissue in McCarey-Kaufman (MK) media. These findings and case reviews are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Utilization of human hematopoietic cell lines for the propagation and characterization of HBLV (human herpesvirus 6).

In 1986, we reported the discovery and isolation of a novel human herpesvirus (HBLV) from AIDS and other lymphoproliferative disorders. Because HBLV is distinct from other members of the herpesvirus family and can infect B- and T-lymphocytes and other human cells (megakaryocytes and glioblastoma cells), we suggested human herpesvirus-6 (HHV-6) as the taxonomic designation for this virus. In cultures from patients' peripheral blood, the evidence of HBLV can be recognized from the appearance of short-lived giant cells (2-10%), which are large, refractile, and are often mono- and binucleated. As these cells degenerate, extracellular virus particles are found in the culture medium. HBLV can infect fresh mononuclear cells, established B- and T-lymphoblastoid cell lines, megakaryocytes and glioblastoma cell lines. HBLV infection can be detected by: a. morphological changes; b. indirect immunofluorescence assay, in situ hybridization, southern blot analysis, polymerase chain reaction amplification; and c. electron microscopy. Because of its wide cell tropism, HBLV DNA sequences have been detected in B-cell lymphomas and short term cultured cells from Sjogren's patients. Expression of HBLV RNA was also detected in sarcoidosis. The etiological role of HBLV in human tumors is unclear. While in vitro data may not necessarily apply to in vivo conditions, the infection of various cell lines from tumors and fresh mononuclear cells suggests HBLV involvement in a variety of diseases.

Cell Line↗
PubMed1988

Utilization of human hematopoietic cell lines for the propagation and characterization of HBLV (human herpesvirus 6).

Details of the productive infection of established human cell lines of diverse origin by HBLV (also designated Human Herpesvirus 6) are described in this report. The infection and replication of HBLV in several T and B lymphoid and other cell lines was observed by electron microscopic examination, by the detection of viral antigen expression by indirect immunofluorescence assay (IFA) and by the presence of HBLV DNA by Southern blot hybridization. Several of these cell lines produced large amounts of virus. For this reason and because of the absence of other human herpesviruses, these lines have provided a valuable resource for the preparation of reagents and the development of assays for the detection and characterization of HBLV. The isolation and characterization of new HBLV isolates from patients with chronic fatigue syndrome were also facilitated by using some of the cell lines reported here. The host range of HBLV in established cell lines, therefore, does not appear to be limited to the B lymphocytes, as initially suggested by in vivo studies. The infection of T and B lymphocytes, megakaryocytes and neuronal cells in vitro suggests a need for the evaluation of diverse hematological and neurological disorders to shed light on a possible HBLV involvement.

Blotting, Southern↗
PubMed1988

Angiogenic properties of Kaposi's sarcoma-derived cells after long-term culture in vitro.

Cells derived from lung biopsies and pleural effusions from AIDS patients with Kaposi's sarcoma (KS) of the lungs were established in long-term culture with the aid of conditioned medium from HTLV-II-transformed T cells (HTLV-II CM). These AIDS-KS cells were similar to the so-called spindle cells in KS lesions and had some of their features. They produced factors that supported their own growth (autocrine) and the growth of other cells (paracrine), including umbilical vein endothelium and fibroblasts. That the AIDS-KS cells also expressed potent angiogenic activity was demonstrated by the chorioallantoic membrane assay and by subcutaneous inoculation of AIDS-KS cells into nude mice, which resulted in the development of angiogenic lesions composed of mouse cells and showing histological features similar to those of human KS lesions. These data suggest that AIDS-associated KS and possibly other types of KS may be initiated by signals that induce the growth of particular cells (spindle cells of lymphatic or vascular origin) and the expression of autocrine and paracrine activities.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Kaposi's sarcoma cells: long-term culture with growth factor from retrovirus-infected CD4+ T cells.

Studies of the biology and pathogenesis of Kaposi's sarcoma (KS) have been hampered by the inability to maintain long-term cultures of KS cells in vitro. In this study AIDS-KS-derived cells with characteristic spindle-like morphology were cultured with a growth factor (or factors) released by CD4+ T lymphocytes infected with human T-lymphotropic virus type I or II (HTLV-I or HTLV-II) or with human immunodeficiency virus type 1 or 2 (HIV-1 or HIV-2). Medium conditioned by HTLV-II-infected, transformed lines of T cells (HTLV-II CM) contained large amounts of this growth activity and also supported the temporary growth of normal vascular endothelial cells, but not fibroblasts. Interleukin-1 and tumor necrosis factor-alpha stimulated the growth of the KS-derived cells, but the growth was only transient and these could be distinguished from that in HTLV-II CM. Other known endothelial cell growth promoting factors, such as acidic and basic fibroblast growth factors and epidermal growth factor, did not support the long-term growth of the AIDS-KS cells. The factor released by CD4+ T cells infected with human retroviruses should prove useful in studies of the pathogenesis of KS.

Acquired Immunodeficiency Syndrome↗
PubMed1988

In vitro cellular tropism of human B-lymphotropic virus (human herpesvirus-6).

We investigated the cellular tropism of human B-lymphotropic virus (HBLV) (also designated Human Herpesvirus-6) in vitro by infecting fresh MN cells from normal human adult peripheral blood, umbilical cord blood, bone marrow, tonsil, and thymus. Cultures from all the sources examined contained infectable cells, as shown by the appearance of characteristic enlarged, round-shaped, short-lived cells expressing HBLV-specific markers. Detailed immunological analysis demonstrated that the vast majority of these cells expressed T cell-associated antigens (i.e., CD7, CD5, CD2, CD4, and to a lesser extent, CD8). The CD3 antigen and the TCR-alpha/beta heterodimer were not detectable on the surface membrane, but were identified within the cytoplasm of HBLV-infected cells, by both immunofluorescence and radioimmunoprecipitation assay. A proportion of the HBLV-infected cell population also expressed the CD15 and class II MHC DR antigens. By means of immunoselection procedures it was possible to show that a consistent proportion of HBLV-infectable cells were contained within the CD3-depleted immature T cell population, while the depletion of CD2+ cells completely abrogated the infectability of the cultures. Northern blot analysis confirmed the T cell origin of HBLV-infected cells, demonstrating the expression of full size TCR-alpha and -beta chain mRNA. In addition to fresh T cells, HBLV was able to infect normal T lymphocytes expanded in vitro with IL-2 for greater than 30 d. These results indicate that HBLV is selectively T cell tropic in the course of the in vitro infection of normal mononuclear cells and may therefore be directly involved in the pathogenesis of T cell related hematological disorders. In particular, in light of the cytopathic effect exerted in vitro on CD4+ T lymphocytes, a possible role of HBLV in immune deficiency conditions should be considered.

Adult↗
PubMed1988

Antibody prevalence to HBLV (human herpesvirus-6, HHV-6) and suggestive pathogenicity in the general population and in patients with immune deficiency syndromes.

Detailed serologic screening showed an antibody prevalence to HBLV (HHV-6) in the general population of 26% if very strict criteria for antibody positivity were applied. Lower and borderline antibody titers yet may be found in up to 63% of the population. Only 17% of these persons have clinical symptoms; in the majority infection remains silent. HHV-6 infection apparently occurs already quite early in life, and initial symptoms can occur, such as short-term high fever, sore throat, local lymphadenopathy and skin rash. Lesions disappear without specific treatment. The frequency of positive antibody tests at higher titers rises in patients with immune deficiency and with atypical lymphoproliferative diseases to 60 and 75%. The rise in antibody titers is associated in patients with immune deficiency by characteristic shifts of blood lymphocyte populations, essentially by increase in immature T-lymphocytes. Highest titers are found in patients with lymphoproliferative syndromes, yet the percentage of atypical lymphoid cells harboring the viral genome is low (about 2% of seropositive patients). Thus it appears, that HBLV, similar to other herpesviruses such as Epstein-Barr virus, usually causes a silent seroconversion, yet may be associated with variable clinical pathology when persisting in an active state. Its pathogenic effect might be rather a cofactor contributing to immune disturbance than overt oncogenicity.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Molecular studies of HHV-6.

Methods for the purification of enveloped HHV-6 virions and the viral DNA are presented. The viral genome is estimated to be 170,000 base pairs in size and does not appear to contain inversions due to absence of submolar bands by restriction enzyme analyses. The genomes of two independent HHV-6 isolates, HHV-6GS and HHV-6Z29, showed restriction enzyme site pleomorphism. Large scale purification of enveloped HHV-6 was achieved by continuous flow centrifugation utilizing sucrose gradients, DNAse 1 treatment and banding on 10-30% Dextran T10 gradients. The viral proteins were visualized on high resolution two dimensional polyacrylamide gels and the proteins recognized by serum antibody from patient GS were detected by HR2D Western blot analysis and radioimmunoprecipitation assay. The major antigenic proteins were 200, 120, 80, 72, 30 and 19 kDa.

Blotting, Western↗
PubMed1988

Polymerase chain reaction amplification and in situ hybridization for the detection of human B-lymphotropic virus.

Polymerase chain reaction amplification (PCR) is a recently described technique that allows for the amplification of a given sequence of DNA. It can be used to reliably amplify sequences of up to 3 kb within hours. The amplified sequence can then be recognized by hybridization with a specific probe after transfer onto nitrocellulose or nylon paper. We used PCR to recognize human B-lymphotropic virus (HBLV or HHV-6) specific sequences in various tumors as well as in the blood of patients with AIDS. Sixty-three specimens of DNA extracted from peripheral blood of patients with AIDS as well as DNA extracted from various lymphoproliferative disorders were analysed; 52 out of 63 (83%) patients with AIDS were found to have amplification of the HHV-6 specific sequence; 2 out of the 63 (3%) had equivocal amplification and 9 (14%) were found to be negative. Twenty out of 23 tumors were found to have amplified HBLV-specific sequences. Only one of these tumors was positive by Southern hybridization on restriction enzyme digested genomic DNA. In situ hybridization of clinical specimens using radiolabelled RNA probes or hapten-labelled DNA probes was used to detect the presence of HBLV in tumors. Three tumors of B cell origin were found to be positive for HBLV.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Soluble extracts from a lymphoblastoid cell line modulate simian immunodeficiency syndrome (SAIDS) evolution.

Nineteen Macaca fascicularis monkeys were injected with SIV. They were subsequently divided into 5 groups. Four groups of 4 animals were injected with dialysable extracts (DLE) from a lymphoblastoid cell line which had been previously induced with DLE obtained either from the total lymphocyte population, or from the CD4 or CD8 subpopulations of mice immunized with SIV virus. The other three animals which constituted the control group received saline injections. The animals were kept under observation for a 108-day period, and the values of several biological parameters were compared in a multivariant statistical analysis. On the 108th day, the control group was significantly different from the other groups in the multivariant analysis. Furthermore, the CD4/CD8 ratio and the platelets and CD4 cell counts varied significantly between the groups in the univariant analysis. It is thus surmised that DLE obtained from CD8 cells or the total lymphocyte population of immunized animals may exert a modulating effect on the evolution of SAIDS.

Adjuvants, Immunologic↗
PubMed1988

Diagnosis and differential diagnosis of progressive lymphoproliferation and malignant lymphoma in persistent active herpesvirus infection.

Persistent active Epstein-Barr virus (EBV) and human herpesvirus-6 (HHV-6) infections may be accompanied by extensive lymphoproliferative reactions mimicking malignant lymphoma. Such atypical polyclonal lymphoproliferations (APL) can frequently be separated from malignant lymphoma only by detailed immunopathologic and virologic studies. Recommended procedures include immunotyping of lymphoid cells, extensive viral serology, in situ hybridization and Southern blotting for viral DNA, gene rearrangement and DNA ploidy studies. Clear separation of APL from malignant lymphoma is essential for therapeutic planning.

Diagnosis, Differential↗
PubMed1988

In vitro inhibition of human herpesvirus-6 by phosphonoformate.

HSB-2 cell cultures productively infected with human herpesvirus-6 were treated with the antiviral drugs phosphonoformic acid (PFA), acyclovir (ACV), and gancyclovir (DHPG). ACV and DHPG showed significant toxic effects on uninfected HSB-2 cells, yet only incompletely inhibited viral expression upon infection of the cells. PFA, however, showed little direct toxicity on HSB-2 cells while viral replication was inhibited significantly.

Acyclovir↗