Effects of tunicamycin and monensin on the distribution of highly phosphorylated proteins in cells infected with herpes simplex virus type 1

Wnt modulating agents inhibit human cytomegalovirus replication

Infection with human cytomegalovirus (HCMV) continues to be a threat for pregnant women and immunocompromised hosts. Although limited anti-HCMV therapies are available, development of new agents is desired. The Wnt signaling pathway plays a critical role in embryonic and cancer stem cell development and is targeted by gammaherpesviruses, Epstein-Barr virus (EBV), and Kaposi's sarcoma-associated herpesvirus (KSHV). HCMV infects stem cells, including neural progenitor cells, during embryogenesis. To investigate the role of Wnt in HCMV replication in vitro, we tested monensin, nigericin, and salinomycin, compounds that inhibit cancer stem cell growth by modulating the Wnt pathway. These compounds inhibited the replication of HCMV Towne and a clinical isolate. Inhibition occurred prior to DNA replication but persisted throughout the full replication cycle. There was a significant decrease in expression of IE2, UL44, and pp65 proteins. HCMV infection resulted in a significant and sustained decrease in expression of phosphorylated and total lipoprotein receptor-related protein 6 (pLRP6 and LRP6, respectively), Wnt 5a/b, and β-catenin and a modest decrease in Dvl2/3, while levels of the negative regulator axin 1 were increased. Nigericin decreased the expression of pLRP6, LRP6, axin 1, and Wnt 5a/b in noninfected and HCMV-infected cells. For all three compounds, a correlation was found between expression levels of Wnt 5a/b and axin 1 and HCMV inhibition. The decrease in Wnt 5a/b and axin 1 expression was more significant in HCMV-infected cells than noninfected cells. These data illustrate the complex effects of HCMV on the Wnt pathway and the fine balance between Wnt and HCMV, resulting in abrogation of HCMV replication. Additional studies are required to elucidate how HCMV targets Wnt for its benefit.

Generation and characterization of a defective HIV-1 Virus as an immunogen for a therapeutic vaccine

BACKGROUND

The generation of new immunogens able to elicit strong specific immune responses remains a major challenge in the attempts to obtain a prophylactic or therapeutic vaccine against HIV/AIDS. We designed and constructed a defective recombinant virus based on the HIV-1 genome generating infective but non-replicative virions able to elicit broad and strong cellular immune responses in HIV-1 seropositive individuals.

RESULTS

Viral particles were generated through transient transfection in producer cells (293-T) of a full length HIV-1 DNA carrying a deletion of 892 base pairs (bp) in the pol gene encompassing the sequence that codes for the reverse transcriptase (NL4-3/ΔRT clone). The viral particles generated were able to enter target cells, but due to the absence of reverse transcriptase no replication was detected. The immunogenic capacity of these particles was assessed by ELISPOT to determine γ-interferon production in a cohort of 69 chronic asymptomatic HIV-1 seropositive individuals. Surprisingly, defective particles produced from NL4-3/ΔRT triggered stronger cellular responses than wild-type HIV-1 viruses inactivated with Aldrithiol-2 (AT-2) and in a larger proportion of individuals (55% versus 23% seropositive individuals tested). Electron microscopy showed that NL4-3/ΔRT virions display immature morphology. Interestingly, wild-type viruses treated with Amprenavir (APV) to induce defective core maturation also induced stronger responses than the same viral particles generated in the absence of protease inhibitors.

CONCLUSIONS

We propose that immature HIV-1 virions generated from NL4-3/ΔRT viral clones may represent new prototypes of immunogens with a safer profile and stronger capacity to induce cellular immune responses than wild-type inactivated viral particles.