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P Lusso

Publications and source records attributed to P Lusso.

At least 55 records · Page 3Linked to original sources
PubMed1995

Human herpesvirus 6 in AIDS.

Multiple lines of clinical and experimental evidence suggest that human herpesvirus 6 (HHV-6) may act as an accelerating factor in the natural history of human immunodeficiency virus (HIV) infection. Although, in common with HIV, HHV-6 has a primary tropism for CD4+ T cells, its potential effects on the immune system are broader. For instance, HHV-6 can also infect and kill CD8+ T cells, natural killer cells and mononuclear phagocytes. Here, Paolo Lusso and Robert Gallo suggest that understanding the immunopathogenic role of HHV-6 in the course of HIV infection may shed new light on the complex mechanisms of disease progression in AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Human herpesvirus 6.

HHV-6, the first T-lymphotropic human herpesvirus, is an important novel human pathogen. It is the cause of exanthem subitum in infants and may act as an opportunistic agent in immunocompromised patients. Moreover, several lines of clinical and experimental evidence suggest that HHV-6 may accelerate the progression of HIV infection. Progress in the study of HHV-6 has been rapid, in part as a consequence of the strong current interest in human lymphotropic viruses and their relationship with the immune system. Nonetheless, the full spectrum of diseases linked to this agent is still unknown (Table 2) and animal models of infection have not yet been exploited. The next few years will be crucial for a complete understanding of the potential role of HHV-6 in human disease.

Acquired Immunodeficiency Syndrome↗
PubMed1995

CD26 expression correlates with entry, replication and cytopathicity of monocytotropic HIV-1 strains in a T-cell line.

Experiments to identify cell determinants involved in HIV-1 tropism revealed a specific decrease in the expression of the T-cell activation antigen CD26 after monocytotropic (M-tropic) but not T-cell line-tropic (T-tropic) virus infection of the PM1 T-cell line. The level of CD26 expression in single-cell clones of PM1 correlated with the entry rate and cytopathicity of M-tropic HIV-1 variants, resulting in preferential survival of cells with low CD26 levels after infection. Experiments with recombinant viruses showed that the third hypervariable region of the envelope gp120 plays an important role in this selection process. This study identifies CD26 as a key marker for M-tropic human immunodeficiency virus type 1 (HIV-1) infection and suggests a mechanism for the early loss of CD26-expressing cells in HIV-1-infected individuals.

Amino Acid Sequence↗
PubMed1995

Detection of human herpesvirus 6 in plasma of children with primary infection and immunosuppressed patients by polymerase chain reaction.

A sensitive and specific polymerase chain reaction method for the detection of human herpesvirus 6 (HHV-6) DNA in serum or plasma has been developed. In total, 157 human serum or plasma samples were studied. HHV-6 DNA was detected in 6 (85.7%) of 7 children with exanthem subitum, 3 (23.1%) of 13 bone marrow transplant (BMT) recipients, 4 (22.2%) of 18 human immunodeficiency virus (HIV)-infected patients, 1 (2.6%) of 39 patients with chronic fatigue syndrome, and none of 37 healthy adults. In the HHV-6-positive BMT recipients, HHV-6 plasma DNA was transiently detected during episodes of fever and respiratory infection. In children with exanthem subitum and in 1 HIV-infected patient, the HHV-6 strains were characterized as variant B, whereas variant A was detected in all other patients. Detection of viral DNA in serum or plasma is a marker of active infection that can be used to investigate the role of HHV-6 in human disease.

Adult↗
PubMed1995

Quantitative PCR for human herpesviruses 6 and 7.

A quantitative PCR assay for the detection of human herpesvirus 6 (HHV-6) (variants A and B) and HHV-7 DNAs in clinical samples was developed. The assay uses a nonhomologous internal standard (IS) for each virus that is coamplified with the wild-type target sequence in the same vial and with the same pair of primers. This method allows for a correction of the variability of efficiency of the PCR technique. A standard curve is constructed for each experiment by coamplification of known quantities of the cloned HHV-6 or HHV-7 target templates with the respective IS. Absolute quantitation of the test samples is then achieved by determining the viral target/IS ratio of the hybridization signals of the amplification products and plotting this value against the standard curve. Using this assay, we quantitated the amount of HHV-6 or HHV-7 DNA in infected cell cultures and demonstrated an inhibitory effect of phosphonoformic acid on the replication of HHV-6 and HHV-7 in vitro. As the first clinical application of this procedure, we performed preliminary measurements of the loads of HHV-6 and HHV-7 in lymph nodes from patients with Hodgkin's disease and AIDS. Application of this quantitative PCR method should be helpful for elucidating the pathogenic roles of HHV-6 and HHV-7.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Growth of macrophage-tropic and primary human immunodeficiency virus type 1 (HIV-1) isolates in a unique CD4+ T-cell clone (PM1): failure to downregulate CD4 and to interfere with cell-line-tropic HIV-1.

Human immunodeficiency virus type 1 (HIV-1) isolates derived directly from clinical samples are usually unable to grow in cytokine-independent continuous cell lines, thus hindering the study of their biological features and their sensitivity to humoral and cellular protective immunity. To overcome these limitations, we have derived from the Hut78 T-cell line a CD4+ clone (PM1) characterized by a unique susceptibility to a wide range of HIV-1 isolates, including primary and biologically pure macrophage (M phi)-tropic isolates (e.g., HIV-1BaL), which are unable to infect other human T- or promonocytic cell lines. Both primary and M phi-tropic HIV-1 establish persistent infection in PM1, with sustained levels of virus replication for prolonged periods. Experiments with chimeric viruses containing envelope fragments of HIV-1BAL inserted into the genetic framework of HXB2, a molecular clone derived from the cell-line-tropic isolate HIV-1IIIB, showed the third hypervariable domain (V3) of gp120 to be a critical determinant of the cell line tropism of HIV-1. Nevertheless, the V3 loop of HIV-1BaL was not sufficient to confer on the chimeras a bona fide M phi tropism. The biological characteristics of HIV-1BaL and of a primary isolate (HIV-1(573)) were investigated by using the PM1 clone. Infection of PM1 by HIV-1BaL was critically dependent on the CD4 receptor, as shown by competition experiments with an anti-CD4 monoclonal antibody (OKT4a) or with soluble CD4. However, the amount of soluble CD4 required for inhibition of HIV-1BaL was approximately 100-fold higher than for HIV-1IIIB, suggesting that the affinity of HIV-1BaL for CD4 is significantly lower. Infection of PM1 with either HIV-1BaL or HIV-1(573) failed to induce downregulation of surface CD4 expression and syncytium formation. Analogous results were obtained with a chimeric virus (HXB2[BaL PvuII-BamHI]) encompassing a large portion of gp120 and gp41 of HIV-1BaL, indicating that the env genes contain critical determinants for CD4 downregulation and syncytium formation. Consistent with the lack of CD4 downregulation, persistent infection of PM1 by HIV-1BaL or HIV-1(573) failed to interfere with HIV-1IIIB superinfection, as revealed by the expression of a type-specific V3 loop epitope (M77) and by the induction of extensive syncytium formation. This lack of interference suggests that a direct viral interaction may occur in vivo between biologically diverse HIV-1 strains.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1994

Antisense oligodeoxynucleotide phosphorothioate complementary to Gag mRNA blocks replication of human immunodeficiency virus type 1 in human peripheral blood cells.

Gene-expression modulator 91 (GEM91) is a 25-nt antisense oligodeoxynucleotide phosphorothioate complementary to the Gag mRNA of human immunodeficiency virus type 1 (HIV-1). Cellular uptake and intracellular distribution of GEM91 within cells suggest that this oligomer is readily available for antisense activity. GEM91 inhibited HIV-1 replication in a dose-dependent and sequence-specific manner. In a comparative study, 2 microM GEM91 was as effective as 5 microM 3'-azido-3'-deoxythymidine in blocking virus replication during the 28-day treatment of an HIV-1-infected T-cell line. GEM91 also completely inhibited (> 99%) the growth of three different HIV-1 isolates in primary lymphocytes and prevented the cytopathic effect of the virus in primary CD4+ T cells. Similarly, treatment with GEM91 for 3 weeks of HIV-1/BaL-infected primary macrophages blocked virus replication. Based on GEM91 anti-HIV-activity, safety, and pharmacokinetic profile in animals, a clinical trial was started using this compound as an antisense oligonucleotide drug for the treatment of the acquired immunodeficiency syndrome.

Antigens, CD↗
PubMed1994

CD4 is a critical component of the receptor for human herpesvirus 7: interference with human immunodeficiency virus.

In this study, we demonstrate that the glycoprotein CD4, a member of the immunoglobulin superfamily, is a critical component of the receptor for human herpesvirus 7 (HHV-7), a recently discovered T-lymphotropic human herpesvirus. A selective and progressive downregulation of the surface membrane expression of CD4 was observed in human CD4+ T cells in the course of HHV-7 infection. Various murine monoclonal antibodies to CD4 and the recombinant soluble form of human CD4 caused a dose-dependent inhibition of HHV-7 infection in primary CD4+ T lymphocytes. Moreover, radiolabeled HHV-7 specifically bound to cervical carcinoma cells (HeLa) expressing human CD4. A marked carcinoma cells (HeLa) expressing human CD4. A marked reciprocal interference was observed between HHV-7 and human immunodeficiency virus (HIV), the retrovirus that causes the acquired immunodeficiency syndrome and also uses CD4 as a receptor. Previous exposure of CD4+ T cells to HHV-7 dramatically interfered with infection by both primary and in vitro-passaged HIV-1 isolates. Reciprocally, persistent infection with HIV-1 or treatment with the soluble form of gp120, the CD4-binding envelope glycoprotein of HIV-1, rendered CD4+ T cells resistant to HHV-7 infection. These data indicate that CD4 is critically involved in the receptor mechanism for HHV-7. The antagonistic effect between HHV-7 and HIV could be exploited to devise therapeutic approaches to AIDS.

Binding, Competitive↗
PubMed1994

Biological and molecular characteristics of human herpesvirus 7: in vitro growth optimization and development of a syncytia inhibition test.

Two isolates of human herpesvirus 7 (HHV-7) were recovered from phytohemagglutinin-activated peripheral blood mononuclear cells of a patient with chronic fatigue syndrome and of a healthy blood donor. A genetic polymorphism between the two isolates was detected by Southern blot analysis using a novel HHV-7 genomic clone (pVL8) as a probe. We developed optimized conditions for the in vitro propagation of HHV-7 by using enriched populations of activated CD4+ T lymphocytes derived from normal peripheral blood, resulting in the production of high-titered extracellular virus (> 10(6) cell culture infectious doses/ml). Bona fide syncytia formation was documented both in normal CD4+ T lymphocytes and in the Sup-T1 CD4+ T-cell line following infection with high-titered HHV-7. To identify neutralizing antibodies to HHV-7, a syncytia-inhibition test was developed. Variable titers of syncytia-neutralizing antibodies were detected in all the human sera tested, thus confirming the high prevalence of HHV-7 in the human population.

Antibodies, Viral↗
PubMed1994

Multistage carcinogenesis utilizing human genital cells and human papillomaviruses.

The preponderance of evidence indicates that a subset of human papillomaviruses are important etiological agents for cervical cancer. However, the necessity of other agents as well as cellular events is recognized because not all women with papillomaviruses develop cancer. Therefore, the exact role of papillomaviruses in the multistage carcinogenesis process is unclear. Regulation of specific viral genes is important to the malignant process. The current study demonstrates that human herpesvirus-6, another ubiquitous virus, can infect genital epithelial cells and upregulate the expression of relevant papillomavirus genes. Thus, it can be considered a cofactor for cancer.

Antibodies, Monoclonal↗
PubMed1994

In vitro susceptibility of Macaca nemestrina to human herpesvirus 6: a potential animal model of coinfection with primate immunodeficiency viruses.

Human herpesvirus 6 (HHV-6), a lymphotropic herpesvirus, has been suggested as a potential cofactor in the acquired immunodeficiency syndrome (AIDS). Previous studies indicate that HHV-6 has a restricted range of susceptible species. In this study, we tested the in vitro susceptibility to HHV-6 of Macaca nemestrina (pig-tailed macaque), a species that has been found to be infectable by human immunodeficiency virus type I in vivo and that develops an AIDS-like syndrome following simian immunodeficiency virus (SIV) infection. Two different HHV-6 isolates (HHV-6GS and HHV-6BA), belonging to the two major HHV-6 variants (A and B, respectively), were employed. Both viruses induced a productive and cytopathic infection in phytohemagglutinin-stimulated peripheral blood T lymphocytes from M. nemestrina. In contrast, only HHV-6BA (variant B) was able to replicate in lymphocytes from Macaca mulatta (rhesus macaque). Moreover, HHV-6GS and SIVsmE660 productively coinfected individual M. nemestrina lymphocytes, resulting in increased levels of SIV replication. Genetic sequences of HHV-6 were not amplified by polymerase chain reaction from peripheral blood mononuclear cells of several adult M. nemestrina, suggesting that these animals, unlike humans, are not commonly infected by HHV-6, or a related virus. Thus, M. nemestrina may represent an optimal animal model system to investigate the in vivo interactions between HHV-6 and the primate immunodeficiency viruses.

Animals↗
PubMed1994

Human herpesvirus 6 infects cervical epithelial cells and transactivates human papillomavirus gene expression.

To examine whether human herpesvirus 6 (HHV-6) is capable of infecting human cervical epithelial cells and altering expression of human papillomavirus (HPV) genes, HPV-immortalized or -transformed carcinoma cell lines were infected with HHV-6 variant A. No cytopathic effect was observed in infected cervical cells. However, immunofluorescence indicated that infected cells expressed early-late proteins of HHV-6 by day 3 postinfection. HHV-6 DNA was also detected by Southern blot hybridization after infection and persisted through continued subculture in an episomal state as proven by Gardella gel electrophoresis and fluorescence in situ hybridization. HHV-6 infection enhanced expression of HPV RNAs encoding the viral oncoproteins E6 and E7. Transient transfection assays showed that two HHV-6 molecular clones, pZVB-70 and pZVH-14, upregulated transcription 9- to 15-fold from a receptor plasmid containing the HPV type 18 regulatory sequences which control transcription in vivo. Cervical carcinoma cells infected with HHV-6 induced more rapid development of tumors in mice than did noninfected cells. These results are the first evidence that human cervical epithelial cells can be infected with HHV-6 and that HHV-6 contains transactivators which stimulate the HPV-transforming genes.

Animals↗
PubMed1994

Cryptic nature of envelope V3 region epitopes protects primary monocytotropic human immunodeficiency virus type 1 from antibody neutralization.

Characterization of biological and immunological properties of human immunodeficiency virus type 1 (HIV-1) is critical to developing effective therapies and vaccines for AIDS. With the use of a novel CD4+ T-cell line (PM-1) permissive to infection by both monocytotropic (MT) and T-cell-tropic virus types, we present a comparative analysis of the immunological properties of a prototypic primary MT isolate of HIV-1 strain JR-CSF (MT-CSF) with those of a T-cell-tropic variant (T-CSF) of the same virus, which emerged spontaneously in vitro. The parental MT-CSF infected only PM-1 cells and was markedly resistant to neutralization by sera from HIV-1-infected individuals, rabbit antiserum to recombinant MT-CSF gp120, and anti-V3 monoclonal antibodies. The T-CSF variant infected a variety of CD4+ T-cell lines, contained positively charged amino acid substitutions in the gp120 V3 region, and was highly sensitive to antibody neutralization. Neutralization and antibody staining of T-CSF-expressing cells were significantly inhibited by HIV-1 V3 peptides; in contrast, the MT strain showed only weak V3-specific binding of polyclonal and monoclonal antibodies. Exposure of PM-1 cells to a mixture of both viruses in the presence of human anti-HIV-1 neutralizing antiserum resulted in infection with only MT-CSF. These results demonstrate that although the V3 region of MT viruses is immunogenic, the target epitopes in the V3 principal neutralizing domain on the membrane form of the MT envelope appear to be cryptic or hidden from blocking antibodies.

Amino Acid Sequence↗
PubMed1994

Detection of human herpesvirus 6 and human papillomavirus 16 in cervical carcinoma.

A subset of human papillomaviruses (HPVs) is associated with the majority of cervical cancers; however, cofactors appear to be required for carcinogenic progression of HPV-induced neoplasia. As human herpesvirus-6 (HHV-6) was recently shown to infect cervical epithelial cells in vitro and activate transcription of HPV-transforming genes, human cervical dysplasia and cancers were analyzed for the presence of HHV-6 by multiple methods, including polymerase chain reaction, slot blot, Southern blot, and in situ hybridization. HHV-6 DNA sequences were detected in 6 of 72 cases of squamous cervical carcinoma and cervical intraepithelial neoplasia. HPV-16 was found in four of the HHV-6-positive cases (two squamous cervical carcinomas and two cervical intraepithelial neoplasias). None of the 30 normal cervices and biopsies of patients with cervicitis was positive for HHV-6 DNA. These results are the first suggestion of an in vivo association between HHV-6 and some cervical neoplasia.

Carcinoma, Squamous Cell↗
PubMed1993

Loss of a neutralizing epitope by a spontaneous point mutation in the V3 loop of HIV-1 isolated from an infected laboratory worker.

The third hypervariable region, or V3 loop, represents the principal neutralizing domain of the gp120 envelope glycoprotein of human immunodeficiency virus type 1 (HIV-1). Sequential viral isolates from a laboratory worker (LW) accidentally infected with HIV-1IIIB in 1985 were analyzed using type-specific neutralizing monoclonal antibodies directed to the V3 loop. A single amino acid substitution, Ala-->Thr at position 21 in the V3 loop of HIV-1LW isolated in 1987, was shown to determine the loss of the neutralizing epitope recognized by one of the monoclonal antibodies (M77). However, this antibody efficiently recognized linear V3 loop peptides containing either the Ala or Thr residue at position 21, indicating that a local change in conformation was responsible for the epitope loss in the native gp120. Molecular modeling studies, experimentally supported by different amino acid replacements at position 21, indicated that the Ala-->Thr substitution leads to a drastic change in the domain of the V3 loop, which contains the complementary surface for antibody binding. These results provide evidence for the first time that a conformation-dependent epitope within the V3 loop of HIV-1 is involved in the generation of neutralization escape mutants in vivo.

Acquired Immunodeficiency Syndrome↗