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PubMed1981

Suppressive effects of interferon on cell fusion by Sendai virus.

Suppressive effects of human IFN-alpha, IFN-beta and mouse-IFN on syncytium formation in human and mouse transformed cells have been studied using u.v.-irradiated Sendai virus (UV-Sendai virus). After treatment of human RSa cells with 500 units/ml human IFN-alpha for 16 h, the syncytium formation induced by UV-Sendai virus was reduced to less than 10% of controls. The suppressive effect was dependent on the amount of interferon added, and it was blocked by the addition of cycloheximide. Suppression of syncytium formation was also observed on human IFr cells, which are partially resistant to the anticellular effect of interferon but are sensitive to the antiviral effect of interferon. Human IFN-beta also had a suppressive effect on syncytium formation in human transformed cells, and human IFN-alpha, IFN-beta and mouse IFN showed species specificity in their effect on fusion. This anti-cell fusion activity was developed in IFr cells from about 5 h after addition, of IFN-alpha and when the cells were treated with IFN-alpha for 16 h, the resistant state of cell continued for over 20 h after removal of IFN-alpha.

Animals↗

PubMed1987

Diagnostic efficacy of two rapid tests for detection of respiratory syncytial virus antigen.

With the availability of ribavirin therapy for serious respiratory syncytial virus (RSV) infections, rapid diagnostic tests for the detection of RSV antigen are increasingly important. Efficacies of a commercially available enzyme immunoassay (EIA) (Abbott Laboratories, North Chicago, Ill.) and a fluorescent-antibody assay (FA) were evaluated in a study involving 135 specimens from children with respiratory symptoms. A nasal wash specimen was cultured immediately on RSV-sensitive A549 cells; the nasal wash was also used for EIA. FA was performed on a nasopharyngeal swab specimen with bovine anti-RSV and anti-bovine immunoglobulin G antisera (Burroughs Wellcome Co., Research Triangle Park, N.C.). A total of 39 specimens (28%) were tissue culture positive, including 35 EIA-positive and 37 FA-positive samples (sensitivities, 90 and 95%, respectively). All 96 tissue culture-negative specimens were EIA negative (specificity, 100%); 94 of these 96 specimens were FA negative (specificity, 98%). Positive and negative predictive values for the tests were as follows: 100 and 96% for EIA, respectively, and 95 and 98% for FA, respectively. Other viruses, including influenza A virus, adenovirus, enterovirus, and herpes simplex virus, were isolated in nine cases. One adenovirus-positive specimen had a false-positive RSV FA result; all nine specimens were RSV EIA negative. Both tests performed well in our study and provide cost-effective alternatives to tissue culture. The RSV EIA, in particular, uses standard serologic techniques and equipment and does not require expertise in virology. More widespread availability of rapid diagnostic tests for RSV will hopefully result in early and appropriate use of antiviral therapy in patients at risk for serious RSV infections.

Antigens, Viral↗

PubMed1985

Selective cytotoxicity of AIDS virus infection towards HTLV-I-transformed cell lines.

Previously, we reported that cells of the human T-cell lymphotropic virus type I (HTLV-I)-transformed lines MT-2 and MT-4 were extensively killed by infection with AIDS retrovirus HTLV-III. We have investigated this phenomenon more systematically using light and electron microscopy as well as immunofluorescence. The cell lines used in the present studies included 14 of those carrying not only human HTLV-I but also related simian agents and 6 HTLV-I-negative T- and B-cell lines. The results showed that the cytocidal effects occurred in the HTLV-I-transformed cell lines exclusively and were not present in further subcultures. In these cell lines the cytotoxic response was closely correlated with the induction of HTLV-III antigens after virus infection. However, cells of 6 HTLV-I-free lines were not killed to a marked extent by HTLV-III and were passaged as continuous producers of AIDS virus. Only 2 cell lines were resistant to the cytocidal effect of HTLV-III among 14 HTLV-I carrying cell lines. They were also resistant to the replication of infected HTLV-III. This AIDS virus-specific cytotoxic effect observed in HTLV-I-transformed cell lines did not appear to be associated with gene expression of the gag and pXs region of HTLV-I genomes. This result may indicate that HTLV-III specifically interferes with some steps of HTLV-I transformation.

Acquired Immunodeficiency Syndrome↗

PubMed1992

Possible supplemental mechanisms in the pathogenesis of AIDS.

Multiple and diverse mechanisms have been proposed as supplements to the HIV-1 virus in the destruction of CD4+ cells and the pathogenesis of AIDS. But it is now realized that 100 times more CD4+ cells are infected with HIV-1 than was originally thought to be the case, and many antigen-presenting cells are infected as well. In addition to the direct cytopathic effect of the virus, one or a few supplemental mechanisms may well suffice to explain the progressive loss of CD4+ cells, e.g., the considerable variation in the virus and/or the destruction of uninfected CD4+ cells by one immunological mechanism or another. However, it is not yet possible to state confidently which additional mechanism(s) is important. Identification of the nature of this supplemental process has become essential for successful, nonharmful intervention.

AIDS-Related Opportunistic Infections↗

PubMed1987

Evaluation of an enzyme immunoassay for detection of herpes simplex virus antigen in genital lesions.

To evaluate a non-marketed research prototype of a solid-phase enzyme immunoassay for detection of herpes simplex virus in genital lesions, 154 clinical specimens were collected from 127 men and 27 women with symptoms suggestive of herpes simplex virus infection (erythema, vesicles, ulcers and crustae). The samples were tested using the assay and cultures on four monolayers of human embryonic lung fibroblasts and Vero cells. When the culture was used as reference method, sensitivity was 76.9% and specificity 100% (prevalence 42.4%). Comparison of results by patient group showed that sensitivity was highest in material from patients with vesicles and ulcers. The highest sensitivity was obtained in specimens which developed a cytopathological effect within 48 h and in specimens with three or four positive cell cultures. These findings suggest that the assay is more successful in specimens with high virus titres. The enzyme immunoassay was found to be a rapid, moderately sensitive, highly specific test for detection of herpes simplex virus from genital lesions, but the usefulness of the assay is limited and culture methods should be preferred.

Animals↗

PubMed1978

Virus shedding by SV40-transformed human cells.

Cultures of human cells transformed by SV40 were found to release infectious virus, even after several passages in vitro. Virus shedding by these cultures did not depend on propagation of virus from cell to cell, as it was not affected by anti-SV40 antiserum that could effectively block virus propagation in acutely infected cells. Cells transformed by the 'early' temperature-sensitive mutant tsA30, and maintained at the restrictive temperature of 39 degrees, shed virus in reduced amount. Finally, xeroderma pigmentosum cells transformed by SV40 were also found to release virus, indicating that the enzymes of excision and repair of UV-induced damage to DNA probably were not involved in the molecular mechanism underlying virus shedding.

Antibodies, Viral↗

PubMed1995

[Follicular conjunctivitis caused by an adenovirus. The characterization of its strains by restriction endonucleases].

A study of conjunctivitis cases with a possible viral cause was carried out in Havana City during June and August, 1993. Thirty seven cases from "Ramón Pando Ferrer" Ophthalmological Hospital were studied, of whom 13 isolations (35.1%) in cell culture of Hela cells were obtained. Isolations showed a cytopathic effect characteristic of Adenovirus. A direct immunofluorescence with conjugated serum of rabbit specific to Adenovirus was performed and results were positive in 100% of cases. A DNA restriction analysis of each isolated was performed for their classification. Restriction endonucleases SmaI and Hind III were used and 2 isolates were classified as Adenovirus type 3, and 6 as Adenovirus type 7b, 4 out of 13 isolates were not classified because of the degradation of the genetic material.

Adenovirus Infections, Human↗

PubMed1984

Evaluation of a commercial enzyme-linked immunosorbent assay for detection of herpes simplex virus antigen.

A commercial enzyme-linked immunosorbent assay (ELISA) for detection of herpes simplex virus (HSV) antigen in clinical specimens and culture lysates was evaluated. A total of 1,155 specimens and an additional 335 cell culture lysates were tested by ELISA, and results were compared to those obtained by cell culture in primary rabbit kidney, human foreskin, and MRC-5. The sensitivity and specificity of the direct test were 52.5 and 96.9% and those of the culture lysate test were 98.7 and 96.9%, respectively. The sensitivity of the direct ELISA correlated with early cytopathic effect in cell culture and varied with specimen source, ranging from 100% with skin lesions to 40.9% with cervical swabs. Of 60 cervical specimens from asymptomatic individuals, 22 (36.6%) yielded false-positives, which may be due to noninfectious HSV. No reproducible cross-reactions were found with other viruses isolated. The Ortho HSV ELISA was found to be rapid, sensitive, and specific for detection of HSV from cell culture lysates, but it needs reevaluation for direct specimen testing, in particular for screening of asymptomatic obstetrical patients.

Antigens, Viral↗

PubMed1985

Effects of human interferon on cell proliferation and antigens induced by Epstein-Barr virus in epithelial hybrid cells derived from nasopharyngeal carcinoma.

The effects of human leukocyte interferon (HulFN-alpha) and fibroblast interferon (HulFN-beta) on cell growth and induction of antigens related to Epstein-Barr virus (EBV) in a nasopharyngeal carcinoma hybrid cell line (NPC-KT) were studied. HulFN-alpha showed little antiproliferative and anti-EBV effect on NPC-KT cells. On the other hand, HulFN-beta showed modest antiproliferative effect on NPC-KT cells; the effect was dependent on time and HulFN-beta concentration. HulFN-beta alone was ineffective in inhibiting EBV-related antigens, but NPC-KT cells treated for more than 1 week with HulFN-beta inhibited the action of the chemical inducer of EBV, n-butyric acid, and the appearance of EBV-induced early antigen and EB viral capsid antigen was inhibited more than 50% compared with NPC-KT cells treated with n-butyric acid alone.

Antigens, Viral↗

PubMedDate not supplied

[Adducts of 3'-azido-2,3'-dideoxythymidine 5'-phosphate or 5'-phosphonate as inhibitors of cytopathic effect and transformation of cells under the influence of retroviruses in cell culture].

Inhibition of HIV-1- or HIV-2-induced cytopathicity and (Moloney) murine sarcoma virus (MSV)-induced cell transformation by amino acid and amino alcohol adducts of either 3'-azido-2',3'-dideoxythymidine 5'-monophosphate (AZTMP) or 5'-hydrogenphosphonate (AZTHP) were investigated. Both types of nucleotide adducts inhibited replication of HIV-1 and HIV-2 in MT-4 cells at a 1.5- to 3-fold higher EC50 (50% effective concentration) than AZT; and, also, selectivity indexes of these adducts were approximately 1.5 to 3-fold lower than that of AZT. The activity of the AZTMP and AZTHP adducts against MSV-induced transformation of C3H/3T3 cells was equal to or only slightly inferior than that of AZT, but their toxicity was 10-fold lower, so that their selectivity indexes were 2- to 7-fold higher. The nature of the aminoacyl component of the adducts significantly influence the antiretroviral activity of the test compounds.

3T3 Cells↗

PubMed1988

A test for the relative potency of herpes simplex virus vaccines based upon the female guinea-pig model of HSV 2 genital infection.

An ELISA for total herpes simplex virus (HSV) 1 antigen content and a test of immunogenicity based upon the female guinea-pig model of HSV 2 genital infection were applied to two samples from batches of HSV 1 subunit ('Skinner') vaccine. The ELISA was reproducible within an approximately threefold limit of error and batches 1 and 2 were indistinguishable in antigen content. The effects of vaccination in the guinea-pig model were assessed by a statistical analysis of scores derived from the principal clinical signs, vaginal oedema and lesions on the external genitalia. The statistical power of the guinea-pig assay was such that reductions in the severity of illness approaching 40% would be significant (P less than 0.05) on 90% of occasions. The ability to make quantitative estimates of immunogenicity will prove useful in the quality control of HSV vaccine batches which are destined for clinical trials in man.

Animals↗

PubMed2001

Live attenuated measles virus induces regression of human lymphoma xenografts in immunodeficient mice.

Derivatives of the Edmonston-B strain of measles virus (MV-Ed) are safe, live attenuated measles virus (MV) vaccines that have been used worldwide for more than 30 years. The cytoreductive potential of MV-Ed has been investigated in murine models of both aggressive and indolent B-cell lymphoma in severe combined immunodeficient (SCID) mice. The rationale for these studies was generated by experience with viral fusogenic membrane glycoproteins as cytotoxic genes and the recognition of the potential of replicating viruses in the treatment of human malignancy. Intratumoral injection of both unmodified MV-Ed and a strain of MV-Ed genetically modified by the addition of a beta-galactosidase reporter gene (MVlacZ) induced regression of large established human lymphoma xenografts, in contrast to control therapy with UV-inactivated virus, in which all tumors progressed. The antitumor effect still occurred in the presence of passively transferred anti-MV antibody. Intravenous administration of MV also resulted in considerable slowing of tumor progression. Analysis of sections of residual tumor confirmed replication of MV within the tumors. Thus, the vaccine strain of MV mediates regression of large, established human B-cell lymphoma xenografts in SCID mice, and proof of principle is established that MV is oncolytic for lymphomas in vivo. Attenuated MVs may have value as a novel replicating-virus therapy for this group of disorders. (Blood. 2001;97:3746-3754)

Animals↗

PubMed1987

Neutralizing antibodies and the course of HIV-induced disease.

The capacity to neutralize the human immunodeficiency virus (HIV) in vitro was examined in 52 sera obtained from 23 seropositive individuals in addition to 7 negative control sera. Neutralization was measured as the activity of a serum to protect MT-4 cells against the cytopathic effect of HTLV-IIIB. Virus neutralization depended on HIV antibodies. Some sera had HIV neutralizing antibody titers of several thousands. All serum samples had been titrated in two ELISAs based either on disrupted HTLV-IIIB or on a bacterially synthesized polypeptide (ENV-80) of gp41 as a test antigen. The correlation of neutralizing activity of the sera with ELISA titers was low. A correlation of serum neutralizing titers with the stage of the disease could not be observed. However, in a longitudinal study with 6 patients over up to 22 months an increase in neutralizing antibodies seemed to protect against progression of the disease. The implications of these findings for antibody treatment and vaccine development are discussed.

AIDS-Related Complex↗

PubMed1983

Rapid detection of herpes simplex virus and varicella-zoster virus in clinical specimens by the use of Staphylococcus aureus rich in protein A.

Herpes simplex virus (HSV) type 1 and type 2 and varicella-zoster virus (VZV) were detected in cytospin preparations from clinical material by using specific antisera and Staphylococcus aureus, Cowan 1 strain, rich in protein A (SRA). Virus was isolated in tissue culture from 22 of the 30 specimens submitted for examination. Eighteen isolates showed cytopathic effect characteristic of HSV infection and 4 of VZV. In the cytospin preparations of the same samples HSV was detected in 15, two contained too few cells to allow a reliable diagnosis and one sample was negative when the SRA reagent was used. In the cytospin preparations of 2 of the 8 samples, which did not show cytopathic effect on isolation in tissue culture, HSV was detected by the SRA. This points to the possible presence of inactive virus in the specimens. All 4 cases of VZV infection were diagnosed correctly with the staphylococcal reagent. No reaction was observed between VZV antigens and rabbit anti-HSV sera. Cells in which viral infection was detected by specific antisera and SRA did not show staphylococcal adherence to their surface after interaction with normal rabbit or normal human serum. Similarly, cells from healthy donors, treated with positive and negative sera were found negative. The method is easy to perform and results can be obtained within three hours from the time specimens are received at the laboratory. Its use offers a rapid diagnosis in suspected cases of herpetic infections in which early therapy is recommended.

Antibodies, Viral↗

PubMed1985

Microcarriers in combination with enzyme immunofiltration and immunofluroescence for the detection of herpes simplex virus antigens in culture.

A microcarrier culture system in combination with enzyme immunofiltration with a herpes simplex virus (HSV) group monoclonal antibody was found to be as sensitive as immunofluorescence for the detection of HSV type 1 (HSV-1) in cell cultures and to give specific identification at the same time as the appearance of the cytopathic effect with very high infectious inocula and within 10 to 24 h of the appearance of the cytopathic effect with very high infectious inocula and within 10 to 24 h of the appearance of the cytopathic effect with low to high inocula. Multiplicities of infection from 10(-5) to 10(1) were tested at 8 to 96 h postinfection. When applied to the identification of HSV-1 and HSV-2 in cultures of clinical samples, the system detected HSV antigens in 50% of the samples after 2 days and in 100% of the samples after 3 days. With 2 ml of microcarrier suspension and with 50 to 300 microliter per sample, several portions are available for replicate and sequential sampling without destroying the culture. The system requires only that 2 X 10(5) microcarriers be added to the culture tube at the time or before it is seeded with cells, at an extra cost of 6 cents (U.S.) per tube and little extra labor.

Antigens, Viral↗

PubMed1980

In vitro production and titration assays of B-tropic retroviruses isolated from C57BL mouse tumors induced by radiation leukemia virus (RadLV-Rs): effect of dexamethasone.

The effect of dexamethasone (DXM) on the replication and titration assays of B-ecotropic radiation leukemia virus (RadLV-Rs) isolates was examined. The drug was shown to enhance in vitro virus release by otherwise low producer permissive cells. DXM also stimulated infectivity and focus formation in murine S+L--permissive cells and shortened the time-appearance of virus-induced foci. In contrast to foci observed in nontreated cultures, which are generally abortive and composed of only a few morphologically transformed cells, those obtained with DXM were comparable to those induced by ecotropic retroviruses with a potent helper activity for murine sarcoma virus. In addition, DXM increased virus-induced XC cell fusion. These fundamental data allowed a more abundant in vitro production of the B-ecotropic RadLV-Rs virus isolates as well as precise infectivity titration assays.

Animals↗

PubMed1984

Lymphadenopathy associated virus and its etiological role in AIDS.

Lymphadenopathy associated virus (LAV) is a novel human retrovirus first reported in 1983. It was isolated from the lymph node lymphocytes of a French homosexual patient with generalized hyperplasic lymphadenopathy. Subsequently LAV was isolated from patients with frank acquired immune deficiency syndrome (AIDS) coming from all the different high-risk groups, while anti-LAV antibodies were detected equally in individuals from all "at-risk" groups. Such a profile is consistent with the virus being the major etiological agent of AIDS. Furthermore its biological properties, namely its cytopathic effect in vitro, its T4-cell tropism as well as the role of the T4 molecule in virus infection explain, at least in part, the pathophysiology of AIDS. The major core (gag) proteins are p18, p25, and p13 which are products of a Pr55 precursor. The major envelope (env) glycoprotein is unusually large (gp110) for a retrovirus and comparable to those of the lentiviruses. Recently the virus has been molecularly cloned. The genome is 9.2 kb long, longer than any other known replication competent retrovirus apart from the lentiviruses. The absence of molecular hybridization between cloned LAV and human T-cell leukemia/lymphoma virus (HTLV) genomes compounds the original and extensive differences noted between these viruses and demonstrates that LAV is a prototype of a new class of human retrovirus.

Acquired Immunodeficiency Syndrome↗

PubMed2002

De novo infection and serial transmission of Kaposi's sarcoma-associated herpesvirus in cultured endothelial cells.

Infection by Kaposi's sarcoma-associated herpesvirus (KSHV) is central to the pathogenesis of the endothelial neoplasm Kaposi's sarcoma (KS) and is also linked to the rare B-cell tumor known as primary effusion lymphoma (PEL). Latently infected PEL cell lines can be induced to enter the lytic cycle and produce KSHV virions. However, such cells do not support de novo infection or serial propagation of KSHV. These limitations have prevented the development of systems for the genetic analysis of KSHV and have impeded a deeper understanding of KS pathogenesis. Here we show that human dermal microvascular endothelial cells immortalized by expression of telomerase can be readily infected by KSHV virions produced by PEL cells. Infection is predominantly latent, but a small subpopulation enters the lytic cycle spontaneously. Phorbol ester (tetradecanoyl phorbol acetate [TPA]) treatment of latently infected cells leads to enhanced induction of lytic KSHV replication, resulting in foci of cytopathic effect. There is no cytopathic effect or viral DNA expansion when infected TIME cells (telomerase-immortalized microvascular endothelial cells) are TPA induced in the presence of phosphonoacetic acid (PAA), an inhibitor of herpesvirus replication. Supernatants from phorbol-induced cultures transfer latent KSHV infection to uninfected cells, which can likewise be induced to undergo lytic replication by TPA treatment, and the virus can be further serially transmitted. Serial passage of the virus in TIME cells is completely inhibited when TPA treatment is done in the presence of PAA. Latently infected endothelial cells do not undergo major morphological changes or growth transformation, and infection is lost from the culture upon serial passage. This behavior faithfully recapitulates the behavior of spindle cells explanted from primary KS biopsies, strongly supporting the biological relevance of this culture system. These findings suggest that either the stability or the growth-deregulatory potential of the KSHV latency program in endothelial cells is more limited than might be predicted by analogy with other oncogenic viruses.

Caenorhabditis elegans Proteins↗