Biomedical subjects

Arianna Calistri

Publications and source records attributed to Arianna Calistri.

8 recordsLinked to original sources

PubMed2006

Highlights from the 5th Annual Meeting of the Italian Society of Virology.

The 5th National Congress of the Italian Society of Virology (SIV) was attended by junior- and senior-level virologists to promote interactions and scientific collaborations among the different areas of Virology and allied sciences. The invited and selected lecturers covered the following topics: General Virology and Viral Genetics; Virus-host Interaction and Pathogenesis; Viral Oncogenesis; Viral Immunology and Vaccines; Anti-viral Therapy; Innovative Diagnostics; Viral Biotechnologies and Cell and Gene Therapy. As in the previous editions (Salata and Palù, 2004; Salata et al., 2005), a specific topic was thoroughly covered in a roundtable. This year the elected subject was "HIV: determinants of pathogenicity and clinical implications." The final program and the abstract book can be found at the web site http://www.siv-virologia.it. This report summarizes the lessons learned from the plenary lectures and the selected oral presentations of the 2005 meeting.

Humans↗

PubMed2005

Human herpesvirus 8 DNA in serum during seroconversion in allogeneic bone marrow transplant recipients.

To determine the prevalence of human herpesvirus 8 (HHV-8) infection, the rate of HHV-8 seroconversion, and the presence of serum HHV-8 DNA after bone marrow transplantation (BMT), we evaluated sera from 187 Italian BMT donor-recipient pairs. Antibodies to lytic and latent HHV-8 antigens were detected by immunofluorescence. Sera of donor-recipient pairs who seroconverted were examined by real-time polymerase chain reaction (RT-PCR). Before BMT, 24 (13%) of 187 donors and 20 (11%) of 187 recipients were seropositive; after BMT, 28 (15%) of 187 recipients were seropositive. Seroconversion occurred in 19 (11%) of 167 recipients seronegative at baseline: 14 (9%) from 149 seronegative donors and five (28%) from 18 seropositive donors (relative risk of seroconversion with BMT from a seropositive donor = 2.96, 95% confidence interval = 1.21 to 7.25; P = .02, two-sided Fisher's exact test). One donor and two recipients who seroconverted after BMT were positive for HHV-8 by RT-PCR. No HHV-8-related complications were observed after a median follow-up of 6 years. BMT-associated HHV-8 seroconversion is relatively common in seronegative recipients from seropositive donor, but factors other than BMT may also contribute to seroconversion.

Adolescent↗

PubMed2004

Inhibition of ShcA isoforms p46/p52Shc enhances HIV-1 replication in CD4+ T-lymphocytes.

HIV-1 infection decreases the number of CD4(+) T-cells, and apoptosis has been suggested among the mechanisms. Proteins of the Shc family are involved in a complex network of signal transduction, differentiation, and apoptotic response to stress in many different cell types. Out of three homologous gene products (ShcA, ShcB, and ShcC), only two splicing variants of ShA are expressed in T-lymphocytes, namely p46Shc and p52Shc. In the present study, we report that inhibition of p46Shc and p52Shc by a dominant negative mutant enhances the yield of HIV-1 particles production without affecting efficiency of viral gene expression in CD4(+)-infected cells. The increase in HIV-1 replication in cells expressing the dominant negative mutant isoform ultimately correlates with a decrease in the percentage of cells entering apoptosis. The data presented suggest that ShcA proteins can play a role in committing CD4(+) T-cells to apoptosis, as a response to HIV-1 infection.

Adaptor Proteins, Signal Transducing↗

PubMed2003

AIP1/ALIX is a binding partner for HIV-1 p6 and EIAV p9 functioning in virus budding.

HIV-1 and other retroviruses exit infected cells by budding from the plasma membrane, a process requiring membrane fission. The primary late assembly (L) domain in the p6 region of HIV-1 Gag mediates the detachment of the virion by recruiting host Tsg101, a component of the class E vacuolar protein sorting (Vps) machinery. We now show that HIV Gag p6 contains a second region involved in L domain function that binds AIP1, a homolog of the yeast class E Vps protein Bro1. Further, AIP1 interacts with Tsg101 and homologs of a subunit of the yeast class E Vps protein complex ESCRT-III. AIP1 also binds to the L domain in EIAV p9, and this binding correlates perfectly with L domain function. These observations identify AIP1 as a component of the viral budding machinery, which serves to link a distinct region in the L domain of HIV-1 p6 and EIAV p9 to ESCRT-III.

Adenosine Triphosphatases↗

PubMed2003

Case report: Kinetics of Epstein-Barr virus load in a bone marrow transplant patient with no sign of lymphoproliferative disease.

The kinetics of Epstein-Barr virus (EBV) load was measured in peripheral blood mononuclear cells of a severely immunocompromised allogeneic bone marrow recipient child, in conditions not associated with lymphoproliferative disease. The viral doubling time was 46.4 hr. The study permitted monitoring EBV clearance from blood, when the anti-rejection therapy was interrupted. Likely, this is the first accurate kinetic assessment of EBV load increasing phase in a clinical context marked by the absence of an overt post-transplant lymphoproliferative disease. According to these data gamma-herpesviruses behave like beta-herpesviruses in being capable of rapid growth.

Bone Marrow Transplantation↗

PubMed2003

Herpes simplex virus type 1 can either suppress or enhance human immunodeficiency virus type 1 replication in CD4-positive T lymphocytes.

It was proposed recently that CEM CD4-positive T cells infected chronically by herpes simplex virus type 1 (HSV-1) and human immunodeficiency virus type 1 (HIV-1) (CEM(HSV/HIV)) may be used as a model for studying HIV/HSV interactions. To ascertain whether HSV-HIV coinfection of T lymphocytes has a role in promoting progression of lentiviral infection, T cells infected chronically by either HSV-1 (CEM(HSV)) or HIV-1 (CEM(HIV)) were challenged with a superinfecting dose of HIV-1 or HSV-1. The results show a positive influence on HIV growth when CEM(HIV) cells were superinfected with HSV-1 to an extent that was dependent on the multiplicity of superinfection used. In contrast, HIV superinfection of CEM(HSV) cells resulted in a delay of HIV-1 production and in a lack of HSV-mediated LTR transactivation. These effects were due to cell growth inhibition and apoptosis, resulting from persistent HSV-1 infection. Treatment of CEM(HSV) with acyclovir inhibited completely the HSV-1 cytopathic effects and allowed efficient HIV-1 replication. These data may be relevant in clarifying the role of HIV/HSV interaction in the pathogenesis of AIDS.

Acyclovir↗

PubMed2002

Seroprevalence and determinants of herpes simplex type 2 infection in an STD clinic in Milan, Italy.

A number of studies have shown that the seroprevalence of herpes simplex virus type 2 (HSV-2) is higher among persons attending clinics for sexually transmitted diseases (STD) than among the general population. The HSV-2 seroprevalence among STD patients, however, varies greatly among studies, possibly reflecting differences in the baseline prevalence of the infection among different general populations or in the distribution of risk factors. A cross-sectional study was carried out to determine the seroprevalence of and the risk factors for HSV-2 infection among 776 HIV-negative persons attending an STD clinic in Milan, Italy. All samples were tested with a commercial HSV type-2 specific gG ELISA test. The HSV-2 seroprevalence was 29.5% (95% CI: 26.3-32.7%). The seroprevalence increased with age, yet it did not differ by gender. Among persons with a current STD, the seroprevalence was 44.3%. At the multivariate analysis, older age was independently associated with HSV-2 infection. A self-reported history of genital herpes was predictive of HSV-2 infection. The agreement between history of genital herpes and HSV-2 seroprevalence was poor, however, stressing that in clinical practice, caution should be used in interpreting the presence or absence of a history of genital herpes as an indicator of the presence or absence of HSV-2 infection. Our data show that HSV-2 seroprevalence among persons attending an STD clinic in Italy is high; thus serological screening for HSV-2 might be advisable for STD patients.

Adolescent↗

PubMed2002

Late assembly domain function can exhibit context dependence and involves ubiquitin residues implicated in endocytosis.

Retroviral Gag polyproteins contain regions that promote the separation of virus particles from the plasma membrane and from each other. These Gag regions are often referred to as late assembly (L) domains. The L domain of human immunodeficiency virus type 1 (HIV-1) is in the C-terminal p6(gag) domain and harbors an essential P(T/S)APP motif, whereas the L domains of oncoretroviruses are in the N-terminal half of the Gag precursor and have a PPXY core motif. We recently observed that L domains induce the ubiquitination of a minimal HIV-1 Gag construct and that point mutations which abolish L domain activity prevent Gag ubiquitination. In that study, a peptide from the Ebola virus L domain with overlapping P(T/S)APP and PPXY motifs showed exceptional activity in promoting Gag ubiquitination and the release of virus-like particles. We now show that a substitution which disrupts the PPXY motif but leaves the P(T/S)APP motif intact abolishes L domain activity in the minimal Gag context, but not in the context of a near full-length HIV-1 Gag precursor. Our results reveal that the P(T/S)APP motif does not function autonomously and indicate that the HIV-1 nucleocapsid-p1 region, which is proximal to p6(gag), can cooperate with the conserved L domain core motif. We have also examined the effects of ubiquitin mutants on virus-like particle production, and the results indicate that residues required for the endocytosis function of ubiquitin are also involved in virus budding.

Amino Acid Motifs↗